Glucocorticoid hormones in relation to environmental exposure to bisphenols and multiclass pesticides among middle aged-women: Results from hair analysis

Bisphenols and pesticides have been shown to alter circulating glucocorticoids levels in animals, but there is limited human data. Moreover, measurements from biological fluids may not be able to reflect long-term status of non-persistent pollutants and glucocorticoids due to the high variability in their levels. Using hair analysis, we examined the associations between glucocorticoid hormones and environmental exposure to multi-class organic pollutants among a healthy female population aged 25-45 years old. Concentrations of four glucocorticoids, four polychlorinated biphenyl congeners (PCBs), seven polybrominated diphenyl ether congeners (PBDEs), two bisphenols and 140 pesticides and their metabolites were measured in hair samples collected from 196 Chinese women living in urban areas. Due to the low detection frequency of some pollutants, associations were explored only on 54 pollutants, i.e. PCB 180, bisphenol A, bisphenol S and 51 pesticides and their metabolites. Using stability-based Lasso regression, there were associations of cortisol, tetrahydrocortisol, cortisone, and tetrahydrocortisone with 14, 10, 13 and 17 biomarkers of exposure to pollutants, respectively, with bisphenol S, p,p'-dichlorodiphenyldichloroethylene, diethyl phosphate, 3,5,6-trichloro-2-pyridinol, thiamethoxam, imidacloprid, fipronil, tebuconazole, trifluralin, pyraclostrobin and 1-(3,4-dichlorophenyl)-3-methylurea being associated with at least three of the four hormones. There were also associations between cortisone/cortisol molar ratio and pollutants, namely dimethyl phosphate, 3-methyl-4-nitrophenol, carbofuran, λ-cyhalothrin, permethrin, fipronil, flusilazole, prometryn and fenuron. Some of these relationships were confirmed by single-pollutant linear regression analyses. Overall, our results suggest that background level of exposure to bisphenols and currently used pesticides may interfere with the glucocorticoid homeostasis in healthy women.

A meta-analysis highlighting the increasing relevance of the hair matrix in exposure assessment to organic pollutants

Owing to a wide range of advantages, such as stability, non-invasiveness, and ease of sampling, hair has been used progressively for comprehensive biomonitoring of organic pollutants for the last three decades. This has led to the development of new analytical and multi-class analysis methods for the assessment of a broad range of organic pollutants in various population groups, ranging from small-scale studies to advanced studies with a large number of participants based on different exposure settings. This meta-analysis summarizes the existing literature on the assessment of organic pollutants in hair in terms of residue levels, the correlation of hair residue levels with those of other biological matrices and socio-demographic factors, the reliability of hair versus other biomatrices for exposure assessment, the use of segmental hair analysis for chronic exposure evaluation and the effect of external contamination on hair residue levels. Significantly high concentrations of organic pollutants such as pesticides, flame retardants, polychlorinated biphenyls and polycyclic aromatic hydrocarbon were reported in human hair samples from different regions and under different exposure settings. Similarly, high concentrations of pesticides (from agricultural activities), flame retardants (E-waste dismantling activities), dioxins and furans were observed in various occupational settings. Moreover, significant correlations (p < 0.05) for hair and blood concentrations were observed in majority of studies featuring pesticides and flame retardants. While among sociodemographic factors, gender and age significantly affected the hair concentrations in females and children in general exposure settings, whereas adult workers in occupational settings. Furthermore, the assessment of the hair burden of persistent organic pollutants in domestic and wild animals showed high concentrations for pesticides such as HCHs and DDTs whereas the laboratory-based studies using animals demonstrated strong correlations between exposure dose, exposure duration, and measured organic pollutant levels, mainly for chlorpyrifos, diazinon, terbuthylazine, aldrin, dieldrin and pyrethroid metabolites. Considering the critical analysis of the results obtained from literature review, hair is regarded as a reliable matrix for organic pollutant assessment; however, some limitations, as discussed in this review, need to be overcome to reinforce the status of hair as a suitable matrix for exposure assessment.

Associations between hair-derived cannabinoid levels, self-reported use, and cannabis-related problems

RATIONALE

As cannabis potency and cannabis use are increasing in newly legalized markets, it is increasingly important to measure and examine the effects of cannabinoid exposure.

OBJECTIVES

The current study aims to assess how hair-derived cannabinoid concentrations - offering insight into three-month cumulative exposure - are associated with common self-report measures of cannabis use and cannabis use-related problems.

METHODS

74 near-daily dependent cannabis users self-reported their quantity of cannabis use, cannabis use-related problems, and estimated cannabis potency. Hair samples were provided to quantify Δ9-THC, CBD, and CBN using LC-MS/MS and THC-consumption was verified by analyzing THC-COOH in hair using GC-MS/MS.

RESULTS

Cannabinoids were detectable in 95.95% of the hair samples from individuals who tested positive on a urine screen for cannabis. Δ9-THC concentrations were positively associated with measures of self-reported potency (relative potency, potency category, and perceived 'high'), but Δ9-THC, CBD, CBN concentrations and THC/CBD ratio were not associated with self-reported quantity of use. Self-reported potency, but not hair-derived concentrations, were associated with withdrawal and craving. Self-reported quantity of cannabis use, but not cannabinoid concentrations, were associated with cannabis use-related problems.

CONCLUSIONS

The use of hair-derived cannabinoid quantification is supported for detecting cannabis use in near-daily users, but the lack of associations between hair-derived cannabinoid concentrations and self-report measures of use does not support the use of hair analyses alone for quantification of cannabinoid exposure. Further research comparing hair-derived cannabinoid concentrations with other biological matrices (e.g. plasma) and self-report is necessary to further evaluate the validity of hair analyses for this purpose.

Hair toxicological analysis of infants and their mothers: a 5-year retrospective study focusing on cocaine

Prenatal and infant exposure to drugs of abuse is an emerging social and public health problem affecting children health and which may relate to child abuse and neglect. Exposure to drugs of abuse may occur through different routes, including intrauterine, breastfeeding, accidental intake, passive inhalation, and intentional administration. Currently, cases of suspected exposure can be investigated by hair toxicological analysis, the interpretation of which is, however, often difficult, leading to consequent difficulties in the management of such cases. In order to provide a contribution in terms of interpretation of the analytical results, this study aimed to search for the possible existence of elements, from a toxicological point of view, indicative towards the route of exposure. A retrospective study was performed on cases of suspected exposure to drugs of abuse in children aged 0-1 year, evaluated at a University Hospital between 2018 and 2022. Data of children hair toxicological analysis were analyzed and then compared with those of their mothers, when available; 41.6% children tested positive for cocaine. The study found a significant correlation between cocaine and benzoylecgonine concentrations, and a benzoylecgonine/cocaine ratio that tends to decrease as the age of children increases. From the comparison with mothers, a child/mother cocaine concentration ratio lower than 1 was found in all cases of hair sampled within the first week of life, and a ratio greater than or equal to 1 in all cases in which the sampling was performed later. These results, if confirmed in a larger cohort, could represent a contribution in the interpretation of cases of infant exposure to drugs of abuse and be integrated in the context of their multidisciplinary evaluation.

Co-occurrence of tetrabromobisphenol a and debromination products in human hair across China: Implications for exposure sources and health effects on metabolic syndrome

The large usage of Tetrabromobisphenol A (TBBPA) in consumer products leads to ubiquitous distribution globally, however, studies on the occurrence of their debromination compounds were rather scarce. Also, though many studies illustrate the effectiveness of hair analysis to assess human exposure to organic pollutants, evidence on the associations with health implications is still fairly limited. Herein, 598 participants from across China were employed to investigate chronic, low-level exposure to TBBPA and debromination products by hair analysis. The geomean concentrations of TBBPA, 2,2',6-tribromobisphenol A (Tri-BBPA), 2,2'- and 2,6-dibromobisphenol A (Di-BBPA), and 2-monobromobisphenol A (Mo-BBPA) were 1.07, 0.145, 0.135, and 0.894 ng/g, respectively, indicating nonnegligible health risks of debromination products. Hair analyte levels correlated with population age and population density among sampling regions. Sexual- and spatial-variations were observed with higher concentrations in females and in E-waste recycling sites. Logistic regression models showed that TBBPA exposure (adjusted odds ratio (OR): 1.02, 95 % confidential interval (CI): 1.01-1.05) was positively associated with risk of metabolic syndrome by adjusting for various covariates. These findings imply usefulness of hair as an alternative biomonitoring tool to assess human exposure to TBBPA and relative health effects, which highlights public concerns on co-exposure to these chemicals.

Association of hair polychlorinated biphenyls and multiclass pesticides with obesity, diabetes, hypertension and dyslipidemia in NESCAV study

Obesity, diabetes, hypertension and dyslipidemia are well-established risk factors for cardiovascular diseases (CVDs), and have been associated with exposure to persistent organic pollutants. However, studies have been lacking as regards effects of non-persistent pesticides on CVD risk factors. Here, we investigated whether background chronic exposure to polychlorinated biphenyls (PCBs) and multiclass pesticides were associated with the prevalence of these CVD risk factors in 502 Belgian and 487 Luxembourgish adults aged 18-69 years from the Nutrition, environment and cardiovascular health (NESCAV) study 2007-2013. We used hair analysis to evaluate the chronic internal exposure to three PCBs, seven organochlorine pesticides (OCs) and 18 non-persistent pesticides. We found positive associations of obesity with hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH) and chlorpyrifos, diabetes with pentachlorophenol (PCP), fipronil and fipronil sulfone, hypertension with PCB180 and chlorpyrifos, and dyslipidemia with diflufenican and oxadiazon, among others. However, we also found some inverse associations, such as obesity with PCP, diabetes with γ-HCH, hypertension with diflufenican, and dyslipidemia with chlorpyrifos. These results add to the existing evidence that OC exposure may contribute to the development of CVDs. Additionally, the present study revealed associations between CVD risk factors and chronic environmental exposure to currently used pesticides such as organophosphorus and pyrethroid pesticides.

Characterization of organic contaminants in hair for biomonitoring purposes

Biological monitoring is one way to assess human exposure to contaminants. Blood and urine are often used as biological matrices, but hair is an innovative and effective tool for quantifying more biomarkers over a wider exposure window. In order to improve the use of hair in exposure assessment, this article identifies relevant compounds in the literature to investigate hair contamination. Statistical analysis was performed to correlate the physical-chemical properties of the relevant compounds and their concentration levels in hair. Phthalates, pyrethroids and organophosphate flame retardants were chosen for further study of the interpretation of hair measurements for exposure assessment. No significant correlation was found between the average concentration levels in the literature and the physical-chemical properties of the selected compounds. This work also explores the properties of hair and the analytical process that may impact the quantification of organic contaminants in hair. The sample preparation method (sampling, storage, washing) were also studied and adaptations were suggested to improve the existing methods.

Identification of potential sources

Recent years have seen growing interest in hair sample analysis to detect organic pollutants (OPs). This biological matrix can be analysed non-invasively for biomonitoring of OPs over a wide exposure window. Obtaining hair sample amounts that meet the needs of the analytical methodology required for the determination of the POs of interest can be challenging, especially in infants. As a result, studies assessing organic pollutants in infant hair have been very scarce. We quantified levels of about 60 OPs, including persistent organic pollutants (POPs), in 110 hair samples from a patient cohort (60 mothers and 50 infants) from Santiago de Compostela (north-western Spain). For each participant we examined relationship between OP levels and corresponding epidemiological parameters using correlations, principal component analysis (PCA), hierarchical cluster analysis, and Multivariate analysis of variance (MANOVA). For many OPs we observed significant correlations with place of residence, parity, and maternal age, as well as pet ownership. Evaluation of dietary habits showed significant associations between levels some OPs and the consumption of fish, molluscs, and cereal. There were significant associations between chlorpyrifos and deltamethrin levels and infant birth characteristics such as birthweight and head circumference. Relations between OP levels in the hair of mothers and their infants were also examined, revealing common sources of exposure for dioxin-like polychlorinated biphenyls (DLPCBs), non-dioxin-like polychlorinated biphenyls (NDLPCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs). Levels of fluoranthene (F), pyrene (P), endrin, and some PBDEs in maternal hair were significantly correlated with those in infant hair. Our findings identified common sources of exposure to OPs of distinct chemical classes.

Disappearance of codeine, morphine and 6-MAM in hair after cessation of abuse

Research on the determination of drugs of abuse in hair has established that drugs can be detected in hair even long after cessation of use. The purpose of this study was to analyze hair samples from chronic opioid users who were beginning a controlled drug cessation program. The study population (n = 15) is involved in a drug rehabilitation program in Santiago de Compostela, Spain. Over a 6-month period, subjects provided hair samples at 2-month intervals, with the first sample collected on the day they began the program. Codeine, morphine, and 6-MAM were analyzed by GC/MS (LOQ = 0.2 ng/mg). Hair tresses were divided into 1 cm segments and analyzed for all analytes 0-1 cm corresponding to the proximal portion to the scalp Following cessation of opioid use, traces of codeine, morphine, and 6-MAM still remained in the newly growing hair segments for a specified period. After 2 months, still 27 % of the users tested positive, and at 4 months, 20 % were positive but only for 6-MAM. However, after 6 months of abstinence, the results were negative for all analytes.

Quantification of the benzimidazole opioid analog isotonitazene in human hair using liquid chromatography-tandem mass spectrometry

Benzimidazole opioids were originally developed from the late 1950s to 1970s as analgesics for medical use, although a lot of them could not be approved as licit medicines because of their severe side effects and physical dependence. Such benzimidazole opioid analogs as abused drug, however, have recently been found in illicit drug markets throughout the world. Isotonitazene is one such benzimidazole opioids, whose analgesic potency can be as much as 500 times greater than that of morphine, according to previous animal studies. In line with this potency, a couple of hundred fatalities related to it were reported to date. In this study, a well validated method for the quantification of isotonitazene in human hair samples using liquid chromatography (LC)-tandem mass spectrometry (MS/MS) was established, and could be applied to authentic samples which were seized by the police security bureau. Isotonitazene concentrations in the seized hair averaged 6.11 pg/mg. The LLOQ and LOD of this method were 1.25 and 2.5 pg/mg, respectively; the calibration curve of the substance in hair samples showed a good linearity in the concentration range of 2.5-250 pg/mg (r > 0.999); the extraction recovery rates were 87.3-105% in the tested range; the inter- and intra-day precisions and accuracies (%biases) were not greater than 9.09% for each determination. Isotonitazene in human hair showed good stability at room temperature and under dark storage conditions for 30 days. As for matrix effect in hair samples, moderate ion suppression of target substances could be found. This is the first report for the analysis of isotonitazene in human hair samples.

Hair concentrations of anti-malarials in returned travellers-the HAIR study: Proof of principle analysis

BACKGROUND

Hair analysis to identify substance use is an established methodology. This could also be a method to monitor adherence to antimalarial drugs. We aimed to establish a methodology to determine hair concentrations of atovaquone, proguanil and mefloquine in travellers using chemoprophylaxis.

METHODS

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous analysis of the antimalarial drugs -atovaquone (ATQ), proguanil (PRO) and mefloquine (MQ), in human hair. The hair samples from five volunteers were used for this proof-of-concept analysis. Three volunteers were taking daily atovaquone/proguanil (ATQ/PRO) chemoprophylaxis and two volunteers were using weekly mefloquine (MQ) chemoprophylaxis.

RESULTS

With this proof-of-principle analysis, we could show that ATQ/PRO and MQ are integrated into the hair matrix. Chemoprophylaxis could be quantified with the established method. In hair segments, maximal concentrations of 3.0 ng/mL/20 mg hair proguanil, 1.3 ng/mL/20 mg hair atovaquone and 78.3 ng/mL/20 mg hair mefloquine were measured. Moreover, malaria drug concentration changes correlated with the time interval since finishing the chemoprophylaxis regimen.

CONCLUSIONS

The validated method was used successfully for the analysis of antimalarial-drug positive hair samples containing atovaquone, proguanil or mefloquine. This research shows that hair can be used for adherence monitoring of chemoprophylaxis and paves the way for larger studies and optimized procedures.

Human hair as a noninvasive matrix to assess exposure to micro-organic contaminants: State of the art review

Human biomonitoring has played an important role in assessing human exposure to micro-organic contaminants (MOCs), including chlorinated persistent organic pollutants, brominated flame retardants, organophosphorus flame retardants, non-persistent pesticides, per- and polyfluoroalkyl substances, phthalate esters, bisphenols, and polycyclic aromatic hydrocarbons. Specifically, human hair holds great promise as a noninvasive matrix for MOC biomonitoring. While human hair has been widely used to detect numerous MOCs over recent decades, its reliability of reflecting body burden is still disputable. As a premise for discussion, it is necessary to understand the mechanisms of MOC incorporation into hair from endogenous and exogenous exposures. Then, standardized protocols must be developed to ensure accurate and reliable results. This review article discusses these issues and provides evidence for the reliability of monitoring MOCs in hair by surveying past reports from various categories of MOCs. We find that most persistent organic pollutants - especially those with a higher octanol-water partition coefficient and lower volatility - can be reliably measured using hair analysis, while internal exposure can be accurately measured using MOC metabolites in hair. Finally, we explore the applications of hair analysis in large-scale surveys, retrospective cohort studies, and epidemiological investigations, highlighting the promise of hair analysis in studying the health risks of MOCs.

Concentrations of LSD, 2-oxo-3-hydroxy-LSD, and iso-LSD in hair segments of 18 drug abusers

Lysergic acid diethylamide (LSD) is one of the most widely abused hallucinogens, which can alter consciousness, produce mental disorder, and cause harmful behavior. 1-Propionyl-LSD (1 P-LSD), a novel derivative of LSD, has the similar hallucinogenic effect. It is a control substance in several countries. 1 P-LSD can act as a prodrug for LSD and is rapidly hydrolyzed to LSD in humans. Therefore, LSD use should be confirmed by the absence of 1 P-LSD and in the detection of LSD. Here, we describe a LC-MS/MS method for the simultaneous extraction of LSD, iso-LSD, 2-oxo-3-hydroxy-LSD, and 1 P-LSD from hair. Hair samples (25 mg) were pulverized by cryogenic grinding in methanol. The limits of detection were 0.2-1 pg/mg and the limits of quantification were 0.5-2 pg/mg. This method was validated and applied to hair samples from 18 suspects who may have used LSD. Segmental hair analysis revealed a decrease in the LSD concentrations from the proximal to the distill end, while 1 P-LSD was not detected in any hair segments. The interpretation of hair analysis results of LSD still remains difficult. Nevertheless, concentrations of LSD and iso-LSD in human hair from 18 LSD users were reported. LSD concentrations were from <LOQ to 4.0 pg/mg (n = 18, median 1.5 pg/mg) in the proximal 0-3 cm segment, from <LOQ to 1.8 pg/mg (n = 8) in the 3-6 cm segment, and from <LOQ to 0.6 pg/mg (n = 4) in the 6-9 cm segment. Iso-LSD ranged from <LOQ to 1.4 pg/mg (n = 4) in the 0-3 cm segment and was detectable only in one 3-6 cm segment. To our knowledge, this is the first study to monitor LSD together with 1 P-LSD in hair.

Quantification of a new recreational drug 2-methoxyqualone in human hair using gas chromatography-tandem mass spectrometry

A method for identification and quantification of 2-methoxyqualone, an newly emerging quinazolinone derivative recreational drug, in human scalp hair was established using gas chromatography (GC)-tandem mass spectrometry (MS/MS). In this report, authentic cases are presented, in which the suspects were seized by police security bureau; the police in China requested our laboratory to identify and quantify the involved drug(s) of abuse in the hair samples of the suspects. After washing and cryo-grinding the authentic hair samples, the target compound was extracted with methanol, and the solvent layer was evaporated to dryness. The residue was reconstituted in methanol and analyzed by GC-MS/MS. 2-Methoxyqualone concentrations in the hair were between 35.1 and 116 pg/mg. The calibration curve of the substance in hair samples showed a good linearity in the concentration range of 10-1000 pg/mg (r > 0.998); the extraction recovery rate, 88.8-105.6 %; the interday and intraday precisions and accuracies (biases), not greater than 8.9 %. 2-Methoxyqualone in human hair had good stability under three different storage conditions at room (20 °C), refrigerated (4 °C) and frozen (- 20 °C) temperatures for at least 7 days. In the present report, simple and rapid quantification method for 2-methoxyqualone in human scalp hair have been established using GC-MS/MS and it could successfully be applied to authentic forensic toxicological cases. To our knowledge, this is the first report for quantification of 2-methoxyqualone in human hair samples.

Mitochondrial DNA Analysis

Mitochondrial DNA (mtDNA) is a 16,569 base pair (bp) circular genome that is passed from generation to generation through the maternal line. mtDNA analysis in the context of the forensic science field usually involves unidentified human remains or missing persons. These cases tend to have more challenging sample types (e.g., rootless hairs, bone, blood, and saliva), and mtDNA analysis can be an additional method to assist in identification efforts. Due to the multifaceted protection of mtDNA within cells, mtDNA is able to be extracted even in cases of extreme degradation. mtDNA analysis for forensic science has been both peer-reviewed in academic journals and has been testified to in criminal court procedures since the late 1990s, allowing for consistent and reliable usage in casework. This chapter describes the general methodology of extracting, amplifying, quantifying, and analyzing an mtDNA sequence for use in forensic casework, specifically for these common items of evidence.

Measurement of hair thyroid and steroid hormone concentrations in the rat evidence endocrine disrupting potential of a low dose mixture of polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) have been shown to influence endogenous hormones levels in animal models, but little is known about the effects of their mixtures. For hormone measurements, hair analysis is a promising approach to provide information on long-term status of hormones. Herein we used hair analysis to assess the combined effects of 13 PAHs on steroid and thyroid hormones levels in a rat model. The PAH mixture was administered orally three times per week to female rats at doses of 0, 10, 20, 40, 80, 200, 400 and 800 μg/kg of body weight for each compound over a 90-day exposure period. Fourteen out of 36 analyzed hormones were detected in rat hair, including pregnenolone (P5), 17α-hydroxyprogesterone (17-OHP4), corticosterone (CORT), dehydroepiandrosterone (DHEA), androstenedione (AD), 3,3'-diiodo-L-thyronine (T2), 3,3',5-triiodo-L-thyronine (T3), and 3,5,3',5'-triiodo-L-thyronine (T4). The PAH mixture significantly elevated P5 and DHEA levels at the doses of 200 and 400 μg/kg but reduced T2 and T3 levels at the highest dose as compared to the control. While P5, DHEA, 17-OHP4 and AD concentrations exhibited inverted U-shaped dose responses, T2, T3 and T4 concentrations exhibited inverse linear dose responses, which are further confirmed by their relationships with hair hydroxylated PAHs (OH-PAHs) concentrations. Likewise, there were significant nonmonotonic relationships of hormone molar ratios (e.g., AD/17-OHP4 and DHEA/CORT ratios) with exposure intensity and OH-PAHs. Overall, our results demonstrate the capability of PAH mixtures to interfere with steroid and thyroid hormones in female rats.

Correlation Between Co Levels in Hair and Blood of Patients Who Underwent Metal-on-metal Hip Arthroplasty

Background

The purpose of this paper is to study the dependence of Co levels in hair on Co levels in blood after metal-on-metal (MoM) hip replacement and prove the suitability of hair analysis coupled to blood analysis in the decision process regarding implant revision evaluation.

Methods

Hair samples of 19 MoM patients having both well-functioning and malfunctioning implants and Co mass concentration levels in blood between 0.2 μg L^-1 and 221.0 μg L^-1 were included. A method based on inductively coupled plasma mass spectrometry was validated and used to measure the Co level in hair.

Results

The Co mass fraction in the hair of patients ranged between 0.011 mg kg^-1 and 0.712 mg kg^-1. A correlation analysis showed a statistically significant positive correlation (r = 0.932, P < .001) between Co in the hair and that in the blood in the full-level range and a statistically nonsignificant positive correlation (r = 0.595, P = .091) in the low-level range.

Conclusions

A correlation between the Co level in the hair and that in the blood exists when the latter is clearly above the 7 μg L^-1 mass concentration threshold suggested for implant revision evaluation. The correlation disappears when the Co level in blood approaches or falls down the mass concentration threshold and that in the hair approaches or falls within the normal population range of 0.004-0.14 mg kg^-1. Accordingly, clinicians could consider a hair analysis coupled to a blood analysis to assess the revision of malfunctioning MoM implants that release metals in patient’s body.

Hormonal profile changes induced by pesticide mixture exposure in female rats revealed by hair analysis

Pesticide exposure has been associated with hormonal disruption in both animals and humans. However, there is limited knowledge of the combined effects of complex mixtures of pesticides on endogenous hormone levels. Here, we used hair analysis to assess the impact of a pesticide mixture comprising 19 components from multiple chemical classes at eight doses of 0-400 μg/kg body weight (bw) three times per week per component on concentrations of 36 steroid and thyroid hormones in female rats over a 90-day exposure period. We detected 13 hormones in rat hair, namely estradiol (E2), androstenedione (AD), testosterone (T), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), pregnenolone (P5), progesterone (P4), 11-deoxycorticosterone (11-DOC), corticosterone (CORT), 3,3'-l-diiodothyronine (T2), 3,5,3'-l-triiodothyronine (T3), 3,3',5'-l-triiodothyronine (rT3), and 3,5,3',5'-l-tetraiodothyronine (T4). In comparison to the control group, hair E2 concentration was significantly lower in the two highest (200 and 400 μg/kg bw) exposure groups, whereas hair DHEAS and CORT concentrations were significantly higher in the 40 μg/kg bw and the highest exposure groups, respectively. Results from generalized additive models suggest that pesticide exposure resulted in monotonic dose responses in hair E2 concentration, CORT concentration and DHEA/CORT molar ratio but nonmonotonic dose responses in hair T concentration, DHEAS concentration, P4/P5 and DHEA/DHEAS molar ratios. The associations of E2, CORT and DHEA/CORT ratio with exposure intensity were confirmed by their significant linear relationships with hair concentrations of at least 23 of the 25 exposure biomarkers analyzed. Our results demonstrate that exposure to low levels of the pesticide mixture evaluated here can alter hair reproductive and adrenal hormones levels.

One-step extraction and determination of 513 psychoactive substances, drugs, and their metabolites from hair by LC-MS/MS

The emergence of new psychoactive substances on the market is a significant problem on a global scale. This type of substance in society is associated with many negative consequences, such as traffic accidents, accidents at work, rape, homicide, poisoning, or overdose deaths. The analysis of these substances in biological samples is very important for further legal action and saving lives. Therefore, laboratories face a tremendous challenge in tackling the evolving drug market. The paper describes the optimization of the analytical LC–MS/MS method to identify and determine 513 psychoactive substances in hair samples. A method of chromatographic separation was developed, and the working parameters of the mass spectrometer were selected for each analyte. The method has been validated, and the results are as follows: the limit of quantification of the developed method ranges from 0.025 to 1.25 ng/mg hair. The mean recovery of the tested analytes ranges from 80 to 120%. The achieved coefficient of variation in within-run precision ranged from 1.05 to 19.99%. The results achieved for BIAS are in the range of ± 20%.

Heavy Metal Concentrations in Malaysian Adults' Hair and Associated Variables in Bukit Mertajam, Penang, Malaysia

The presence of heavy metals in human hair is being tracked to predict health risk, forensics, and environmental monitoring. Heavy metals are typically non-biodegradable and have a lengthy half-life, allowing them to linger in humans and the environment for many years. Heavy metal exposure in hair has been attributed to multiple sources from the environment and food intake. In this study, copper (Cu), nickel (Ni), zinc (Zn), chromium (Cr), manganese (Mn), lead (Pb), and cadmium (Cd) levels were measured in the scalp hair of 50 individuals in Bukit Mertajam, Penang, Malaysia. In conjunction with sampling, subjects' age, gender, lifestyle, diet, and working environment were also obtained through the questionnaire. The Atomic Absorption Spectrometry (AAS) method was used to extract all the metals in the hair samples. The mean concentrations of heavy metals were found to be in the following order (unit of mg/kg): Cr > Zn > Pb > Ni > Cd > Cu. Manganese was detected below the limit of quantitation among the elements (< LOQ). All elements except Mn were higher and comparable to the previous studies' international limit values. Cadmium prevalence was substantially associated with age, smoking habit, dyed hair, and working environment in Pearson's correlation analysis (p ≤ 0.05). Zinc was also found to be related to the working environment. Some elements were observed to be statistically related between heavy metals, Cd/Zn, Cd/Ni, Cr/Ni, and Pb/Ni, whereas smoking habit/dyed hair and dyed hair/working environment were the associated factors for metal distribution that were statistically correlated (p ≤ 0.05). To recapitulate, this study found that the distribution of heavy metals in hair was influenced by associated factors and between heavy metals. It has been indicated that heavy metal exposure to humans is influenced by factors such as geographical location, lifestyle, and working environment.

Quantitation of sibutramine in human hair using gas chromatography-isotope dilution tandem mass spectrometry

PURPOSE

An analytical method for quantitation of sibutramine in human hair using gas chromatography (GC)-isotope dilution tandem mass spectrometry (MS/MS) was newly established. In this article, a case is presented, in which a 3.5-year-old male child accidentally ingested chocolate-like product containing sibutramine, showing various symptoms; he could survived the crisis. About 1 month after the incident, his scalp hair sample was subjected to analysis for the causative sibutramine.

METHOD

After cryo-grinding for the hair sample, target compound was extracted with methanol, and the solvent layer was evaporated to dryness. The residue was reconstituted in methanol and analyzed by GC-MS/MS, using the selected reaction monitoring (SRM) mode with a deuterated isotope internal standard.

RESULTS

The substance was identified as sibutramine; its concentration in the hair sample of the child was 58.6 pg/mg. The calibration curve of sibutramine in hair samples had a good linear relationship in the concentration range of 20-200 pg/mg (r > 0.99); the extraction recovery rate 85.2-91.8%; the interday and intraday precision and accuracy (bias) examined not greater than 9.6%. Sibutramine in human hair had good stability under 3 different storage conditions at room (20 °C), refrigerated (4 °C) and frozen ( - 20 °C) temperatures for at least 7 days.

CONCLUSIONS

It should be expected that the method established in this study would contribute to rapid determinations of sibutramine. To our knowledge, this is the first report describing quantitation of sibutramine in an authentic human hair sample by GC-MS/MS.

Investigating children's chemical exposome - Description and possible determinants of exposure in the region of Luxembourg based on hair analysis

The specific physiology and behaviour of children makes them particularly vulnerable to chemical exposure. Specific studies must therefore be conducted to understand the impact of pollution on children's health. Human biomonitoring is a reliable approach for exposure assessment, and hair, allowing the detection of parent chemicals and metabolites, and covering wider time windows than urine and blood is particularly adapted to study chronic exposure. The present study aims at assessing chemical exposure and investigating possible determinants of exposure in children living in Luxembourg. Hair samples were collected from 256 children below 13 y/o and tested for 153 compounds (140 pesticides, 4 PCBs, 7 BDEs and 2 bisphenols). Moreover, anthropometric parameters, information on diet, residence, and presence of pets at home was collected through questionnaires. Correlations, regressions, t-tests, PLS-DA and MANOVAs, were used to investigate exposure patterns. Twenty-nine to 88 (median = 61) compounds were detected per sample. The highest median concentration was observed for BPA (133.6 pg/mg). Twenty-three biomarkers were detected in ≥ 95% of the samples, including 13 in all samples (11 pesticides, BPA and BPS). Exposure was higher at younger ages (R² = 0.57), and boys were more exposed to non-persistent pesticides than girls. Presence of persistent organic pollutants in most children suggests that exposure is still ongoing. Moreover, diet (e.g. imazalil: 0.33 pg/mg in organic, 1.15 pg/mg in conventional, p-value < 0.001), residence area (e.g. imidacloprid: 0.29 pg/mg in urban, 0.47 pg/mg in countryside, p-value = 0.03), and having pets (e.g. fipronil: 0.32 pg/mg in pets, 0.09 pg/mg in no pets, p-value < 0.001) were identified as determinants of exposure. The present study demonstrates that children are simultaneously exposed to multiple pollutants from different chemical classes, and confirms the suitability of hair to investigate exposure. These results set the basis for further investigations to better understand the determinants of chemical exposure in children.

Micro-segmental hair analysis: detailed procedures and applications in forensic toxicology

PURPOSE

Since the 1980s, the detection sensitivity of mass spectrometers has increased by improving the analysis of drugs in hair. Accordingly, the number of hair strands required for the analysis has decreased. The length of the hair segment used in the analysis has also shortened. In 2016, micro-segmental hair analysis (MSA), which cuts a single hair strand at a 0.4-mm interval corresponding to a hair growth length of approximately one day, was developed. The advantage of MSA is that the analytical results provide powerful evidence of drug use in the investigation of drug-related crimes and detailed information about the mechanism of drug uptake into hair. This review article focuses on the MSA technique and its applications in forensic toxicology.

METHODS

Multiple databases, such as SciFinder, PubMed, and Google, were utilized to collect relevant reports referring to MSA and drug analysis in hair. The experiences of our research group on the MSA were also included in this review.

RESULTS

The analytical results provide a detailed drug distribution profile in a hair strand, which is useful for examining the mechanism of drug uptake into hair in detail. Additionally, the analytical method has been used for various scenarios in forensic toxicology, such as the estimation of days of drug consumption and death.

CONCLUSIONS

The detailed procedures are summarized so that beginners can use the analytical method in their laboratories. Moreover, some application examples are presented, and the limitations of the current analytical method and future perspectives are described.

Quantification of MDMB-4en-PINACA and ADB-BUTINACA in human hair by gas chromatography-tandem mass spectrometry

PURPOSE

To test synthetic cannabinoid (SCs) in parent forms from living human, the hairs seems to be one of the best samples, because of the non-invasiveness upon their collection. The purpose of this study is to establish a method for quantification of MDMB-4en-PINACA and ADB-BUTINACA, the most recently abused SCs in hair samples, using gas chromatography-tandem mass spectrometry (GC-MS/MS).

METHODS

The collected hair samples were washed with a detergent solution, following by water and acetone. After drying cutting them into about 2 mm sections, they were ground by a cryogenic grinder into powder. The 50-mg powder with internal standard(s) plus 1 mL methanol were vortexed, and centrifuged to obtain the supernatant layer. After its evaporation and reconstitution with 50 µL methanol, 1-µL aliquot of it was subjected to analysis.

RESULTS

The standard calibration curves were created for both MDMB-4en-PINACA and ADB-BUTINACA in blank hair samples; good linear curves were obtained in the range of 20-20,000 pg/mg with correlation coefficients greater than 0.99. The limits of detection and limits of quantification were 10 and 20 pg/mg, respectively. Other validation parameters were all satisfactory. The concentrations of MDMB-4en-PINACA obtained from 3 authentic subjects and ADB-BUTINACA obtained from 3 authentic subjects were 26.2-806 pg/mg and 63.1-430 pg/mg, respectively.

CONCLUSIONS

In the present article, the details of simple and rapid quantification of MDMB-4en-PINACA and ADB-BUTINACA in human scalp hair have been established. To our knowledge, this is the first report for quantification of SCs in hair samples by GC-MS/MS.

Chimpanzee exposure to pollution revealed by human biomonitoring approaches

Wildlife is increasingly exposed to environmental pollution, but data illustrating to what extent this exposure can impact health and survival of endangered species is missing. In humans, hair matrix analysis is a reliable tool for assessing cumulative exposure to organic pollutants such as pesticides but has rarely been used in other primates for this purpose. LC/MS-MS and GC/MS-MS multi-residue methods were used to screen the presence of 152 organic pollutants and their metabolites belonging to 21 different chemical families in hair samples from our closest relative, the chimpanzee. Samples were collected from 20 wild chimpanzees in Sebitoli, Kibale National Park, Uganda and 9 captive chimpanzees in the Réserve Africaine de Sigean, France. In total, 90 chemicals were detected, 60 in wild chimpanzees and 79 in captive chimpanzees. The median concentrations of detected chemicals in captive individuals were significantly higher than those in wild chimpanzees. Hair from the captive individuals at RAS was sampled a second time after 6 months in an environment of reduced exposure to these pollutants (diet of organic food, decreased use of plastic food and water containers). The number of chemicals detected in captive chimpanzees reduced from 79 to 63, and their concentrations were also significantly reduced. In the present study we report for the first time the use of hair analysis to detect organic pollutants in primate hair. We conclude that both wild and captive chimpanzees are exposed to a large range of different chemicals through their diet. Our study provides surprising and alarming evidence that besides the direct threats of poaching, deforestation and diseases, wild chimpanzees might be endangered by indirect consequences of anthropic activities. As chimpanzees are our closest relatives, our results should be considered as an alert for human health as well.

Detection of mescaline in human hair samples by UPLC-MS/MS: Application to 19 authentic forensic cases

Mescaline, a natural alkaloid found in the peyote cactus (Lophophora williamsii) in the Americas, has gradually become a drug of abuse in China because of its psychedelic properties. Its intake may lead to hallucinations and confusion or even be life-threatening. Mescaline is classified as a class Ⅰ psychotropic drug in China, which means its use in medicine or scientific research is under strict control of the government. However, studies on surveillance of mescaline abuse in the Chinese population are lacking. A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination and quantification of mescaline in hair. The method had good linearity in the range from 10 to 1000 pg/mg, with the limit of detection (LOD) of 3 pg/mg and the limit of quantitation (LOQ) of 10 pg/mg. The total runtime was 5 min. Acceptable intraday and interday precision (RSD < 15%) and accuracy (bias, -11.2% ∼ 6.8%) were achieved. The recovery was 85.0-101.0%, and the matrix effect was 92.0-105.0%. The validated method was successfully applied to 19 real forensic cases. The concentrations of mescaline in hair ranged from 10 to 784 pg/mg. The method has the benefits of simple sample preparation, high sensitivity, and short running time, making it suitable for large-scale quantitative surveillance analysis of mescaline in forensic toxicology.

Repeated poisoning of the life partner by thallium - a case of questionable Munchausen by adult proxy syndrome with ensuing attempted murder

After the use of thallium as rat poison was banned, the knowledge about the severe and treacherous course of poisonings with this toxic metal has widely been lost. In the present case, the male victim sustained two insidious poisoning attacks in 2017 and 2020 by the perpetrator, his female life partner. In the first poisoning episode, he suffered from increasing heavy pain of the abdomen, stinging pain of both legs, persistent obstipation, hyperesthesia, and, after about 2 weeks, tuft-wise loss of hair as typical symptoms of the thallium poisoning. Within 7 weeks, he was successively examined in six hospitals with a wide variety of diagnostic methods, but a conclusive explanation of the complaints was not found. The possibility of a metal intoxication was then suggested by the perpetrator who privately arranged the analysis of a blood sample with the result of 175 µg/l thallium. Although a criminal poisoning was assumed, the perpetrator was not identified. After the victim left the perpetrator, she subtly executed a second poisoning attack with thallium sulfate (blood level 1230 µg/l after 1 day, urine level 4760 µg/l after 10 days, and hair concentrations 3.26-0.49 from proximal to distal in 9 segments). The perpetrator was sentenced to 10.5 years imprisonment for grievous bodily harm and attempted murder. Because of the behavior of the perpetrator, a Munchausen by proxy syndrome was discussed as a motivation of the first poisoning but was excluded by the psychiatric expert because of a missing antisocial personality disorder.

High lead level in the Alps in XIXth century, learning from the analysis of 138 historical hair stands

Analysis of hair is known to provide useful information about environmental and toxic exposures. Very little historical use has been made of this type of investigation. Here we study 138 human hair samples from 19th century in France. In order to examine the potential association between contamination and historical health impacts, we characterized contamination by 33 elements in a set of hair strands sampled during the last quarter of the 19th century in the Savoy region of France. After a selected washing step on 138 hair strands conserved at the Museum National d'Histoire Naturelle in Paris (France), we assessed the presence of inorganics by ICP/MS, and lead level was higher than values reported in literature. We then compared concentrations and distributions between women and men, sampling locations and crossing gender and geographical origin. Hair lead level was high throughout Savoy at the end of the 19th century: significantly higher for people living in towns or industrial valleys, and lower for those of countryside and mountains areas. Environmental and economic changes (industrialization and urbanization with water adduction and leaded paints), living habits (kitchenware, cosmetics, wine, and tobacco), and local features (mines exploitation, railroad development, and industrialized narrow valleys) could be envisaged for explaining the level of lead contamination. In the same period, the two main industrial valleys of Savoy (Maurienne and Tarentaise) had high rates of endemic goiter and cretinism and among the highest hair lead levels. Other lines of evidence will need to be explore to investigate a possible link between historical Pb exposure and goiter in the study area.

Confirmation of Gelsemium elegans poisoning by UHPLC-MS/MS analysis of koumine, gelsemine, and gelsenicine in hair

A sensitive, accurate, simple, and rapid analytical UHPLC-MS/MS method was developed for identification and quantification of koumine, gelsemine, and gelsenicine in human hair. Approximately 10 mg of hair was extracted with methanol by cryogenic grinding. The limits of detection (LODs) ranged from 1 to 5 pg/mg, and the limits of quantitation (LOQs) ranged from 2 to 10 pg/mg. The method was linear over a concentration range from the LOQs to 1000 pg/mg, and the linear correlation (R²) of the calibration curves was above 0.998 for all three analytes. The bias varied from -6.5-13.1%, while the intra- and inter-day precision relative standard deviation (RSD) values were 4.3-12.4% and 3.7-13.2%, respectively. Recoveries ranged from 79.3% to 103.5%, and matrix effects ranged from 74.3% to 105.5%. The described method was used for the quantitative determination of koumine, gelsemine, and gelsenicine in a human hair sample from a Gelsemium elegans poisoning case. The highest concentrations of koumine, gelsemine, and gelsenicine were 27.2, 18.1, and 4.2 pg/mg, respectively, and corresponded to the segment associated with the ingestion period. To our knowledge, this is the first study to describe hair analysis in a G. elegans poisoning case and to provide quantitative toxicological findings.

Prevalence of cathinones and other new psychoactive substances in hair of parents and children of families with known or suspected parental abuse of conventional illegal drugs

BACKGROUND

Hair analysis of parents and their children was regularly used since 2011 as a diagnostic tool in a social support project for families with known or suspected abuse of conventional illegal drugs and revealed a high incidence of cocaine, cannabinoids, amphetamines, ecstasy and heroin. In this context, the prevalence of new psychoactive substances (NPS) in these families should be important for a realistic estimate of the situation.

METHODS

The extracts of 1537 hair samples from 318 children (age 1-14 years), 44 adolescents and 611 adults, which were collected and tested for conventional drugs between June 2016 and April 2021 and frozen at -20 °C, were reanalyzed by a validated LC-MS/MS method (limits of quantitation 5-24 pg/mg) for 33 cathinones, 10 phenylethylamines, 5 piperazines including the antidepressant trazodone, 2 tryptamines, 9 designer benzodiazepines, 4 synthetic opioids and 4 ketamine-like substances including phencyclidine.

RESULTS

Between one and up to five from 42 of these substances were detected in 227 samples (14.8%). The most frequently detected substances were benzedrone (62x), α-pyrrolidinovalerophenone (41x), N-ethylamphetamine (29x), dimethyltryptamine (13x) and pyrovalerone (11x). The quantification was possible only for 34 results of 15 drugs and the remaining majority of the results were unambiguously identified below LLOQ. The relative frequency of conventional drugs in the 227 NPS positive samples was higher than in all 1310 NPS negative samples for cocaine (69.6% vs. 56.0%), heroin (6-acetylmorphine 8.8% vs. 4.9%), amphetamine (16.3% vs. 7.7%) and MDMA (16.3% vs. 7.0%) but was similar for THC (38.3% vs. 36.3%) and benzodiazepines (1.8% vs. 1.7%). The high prevalence of N-ethylamphetamine can be explained as a byproduct of the illicit amphetamine synthesis from benzaldehyde and nitroethane rather than as a separate drug or as a combined metabolite of amphetamine and ethanol. The isolated appearance of 3-trifluoromethylphenylpiperazine in 9 hair samples collected in January 2017 can be caused either by its use as an NPS or by its formation as a metabolite of the medical drug flibanserin. The results were compared within 17 families whose members were tested at the same time and showed positive NPS results. The detected drugs agreed between both parents only in about half of the cases whereas the drugs found in children's hair was always detected also in hair of one or both parents.

CONCLUSION

The re-testing of hair extracts for NPS after long-time storage in frozen state enables an impression about the relative high prevalence in the tested population group, despite the limitation by partial degradation of the substances and the corresponding impossibility in quantitative assessments. In addition to conventional drugs, the hair test for these substances should be useful in unclear cases of child's welfare endangerment and in family law.

A prospective study on long-term trace metal accumulation in hair: Is there any difference between minimally invasive repair of pectus excavatum and carinatum?

BACKGROUND

To date, there is no study about trace metal level increases in hair after stainless steel pectus bar implantation. We aimed to determine whether there was any significant increase in the levels of trace metals in the hair of children who underwent minimally invasive repair of pectus excavatum (MIRPE) and minimally invasive repair of pectus carinatum (MIRPC).

MATERIALS AND METHODS

In this prospective study, we collected the data of 223 patients who underwent MIRPE and MIRPC between November 2013 and August 2020. The levels of main components of the stainless steel pectus bar ("PES", Medxpert GmbH, Escbach, Germany) namely Cr, Fe, Ni, and Mo in hair were analyzed. The study involved two study groups: A group of patients who underwent MIRPE with a single bar (n = 112) and a group of patients who underwent MIRPC (n = 71). Both groups were analyzed in two different timelines: A group of consecutive patients prior to bar implantation and a group of the same patients who underwent bar removal after a mean time of 34.6 ± 5.1 months.

RESULTS

Statistically significant increases in all studied trace metal levels were observed in the single-bar MIRPE group. In the MIRPC group, the accumulation of studied trace metals was no statistically significant. The double-bar MIRPE group had higher trace metal increase rates compared to single-bar MIRPE group (p>0.05).

CONCLUSION

In our study; increases in iron, chrome, nickel and molybdenum levels were observed in both MIRPE and MIRPC patients by hair trace metal analysis; but these increases were statistically significant in only MIRPE group.

UPLC-MS/MS method for the simultaneous quantification of caffeine and illicit psychoactive drugs in hair using a single-step high-speed grinding extraction - Insights into a cut-off value for caffeine abuse

Caffeine is a commonly consumed psychoactive substance whose addictive potential has long been reported. Excessive caffeine intake may lead to severe health damage or drug addiction problems; however, studies on the surveillance of caffeine abuse by the Chinese population are lacking. This study aimed to propose a concentration value for caffeine based on hair analysis to distinguish excessive intake from normal consumption, and provide an analytical tool for forensic toxicology investigations of caffeine and other frequently abused drugs. A sensitive and accurate ultra-high performance liquid chromatography-tandem mass spectrometry method was developed to detect caffeine and 13 illicit drugs and their metabolites in hair. Thereafter, this method was employed to test 479 real samples. Briefly, the hair samples were washed with water and acetone, and subsequently extracted by one-step high-speed grinding with acetonitrile-buffer solution. The lower limit of quantifications of 0.05 ng/mg for caffeine and THC, and 0.005 ng/mg for others, were achieved for all substances. The results revealed a mean caffeine concentration of 0.78 (range 0.008-3.5 ng/mg) based on 24 healthy volunteers, 55.0 (range 3.07-292.2 ng/mg) based on 52 self-reported caffeine abuse participants, and 5.78 (range 0-140.34 ng/mg) based on 403 drug addicts. The mean caffeine concentration in hair from self-reported caffeine abusers was 70-fold higher than that in hair from healthy volunteers. A tentative cut-off level of 5.5 ng/mg as an indicator of excessive caffeine consumption was developed based on receiver operating characteristic analysis. Additionally, the assessment of 403 hair samples from drug addicts indicated that illicit drug abusers had potential for caffeine abuse, especially polydrug users. This hair analysis method serves as a useful tool for the large-scale surveillance of caffeine and illicit drug abuse.

History of hair analysis by mass spectrometry imaging

In conventional forensic science, blood and urine have been used for drug testing. However, hair has recently attracted attention as a new source of biological information in this milieu. Drugs and biomolecules taken up by the hair from the capillaries of the scalp are retained in the hair without being degraded by enzymes, migrating toward the tip of the hair as the hair grows at a constant rate. As a result, drug residues are stored in the hair in chronological order. In recent years, mass spectrometry imaging (MSI) has been developed to visualize the history of drug use in hair samples, making use of this unique property. Advances in this drug testing technique are expected to create a powerful deterrent for drug abuse and doping. In this paper, we introduce the history of hair research using MSI and the evolution of instruments, matrices, and methods.

Sensitive determination of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol and complementary cannabinoids in hair using alkaline digestion and mixed-mode solid phase extraction followed by liquid-chromatography-tandem mass spectrometry

Hair drug testing can be used for the evaluation of cannabis use with a large detection window, and is required for professional driving license granting in Brazil. A positive hair result for cannabis use requires quantification of the metabolite THC-COOH above the cutoff value of 0.2 ng/g. The achievement of such lower limit of quantification is challenging, particularly with the use of liquid chromatography coupled to triple quadrupole mass spectrometers (LC-MS/MS). In this study, a very sensitive LCMS/ MS assay for the simultaneous quantification of THC-COOH along with THC, CBD, and CBN was developed and validated. Sample preparation was based on hair hydrolysis, followed by selective ion-exchange solid-phase extraction. The extraction yield was 101.5-101.6% for THC-COOH, 92.3-97.4% for THC, 89.7-95.2% for CBN, and 104.9-121.1% for CBD. Internal standard corrected matrix effects were - 2.7 to - 1,1 for THCCOOH and - 11.5 to - 0.1% for the other analytes. The lower limit of quantification was 01 ng/g for THC-COOH and 25 ng/g for THC, CBD, and CBN. The assay fulfilled validation guidelines acceptance criteria. The measurement uncertainties were determined and the assay was ISO17025 accredited, being currently used in routine testing.

Hair analysis for New Psychoactive Substances (NPS): Still far from becoming the tool to study NPS spread in the community?

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The detection of 280 NPS has been reported to be enabled through hair analysis.

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The LODs/ LOQs for these NPS are as low as pg/mg of hair.

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The NPS hair concentrations in clinical/forensic samples are considerably higher than the respective LOD.

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Untargeted-mass spectroscopic detection techniques could advance NPS hair analysis.

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NPS hair analysis could become the tool to monitor the extent of NPS use worldwide.

In this review article, we performed an overview of extraction and chromatographic analysis methods of NPS in hair from 2007 to 2021, evaluating the limit of detection (LOD), limit of quantification (LOQ), limit of reporting (LOR), and limit of identification (LOI) values reported for each NPS. Our review aimed to highlight the limitations of modern hair analytical techniques, and the prerequisites for the proper evaluation and use of analytical results in relation to the objectives of NPS hair analysis. In the selected studies the detection of a total of 280 NPS was reported. The detected NPS belonged to seven classes: synthetic cannabinoids with 109 different substances, synthetic opioids with 58, cathinones with 50, phenethylamines with 34, other NPS with 15, tryptamines with ten, and piperazines with four substances. The NPS hair analysis of real forensic/ clinical cases reported the detection of only 80 NPS (out of the 280 targeted), in significantly higher levels than the respective LODs. The analytical protocols reviewed herein for NPS hair analysis showed continuously growing trends to identify as many NPS as possible; the extraction methods seem to have a limited potential to improve, while the various mass spectroscopic techniques and relevant instrumentation provide an enormous field for development and application. Hair is a biological indicator of the past chronic, sub-chronic, and, even, in certain cases, acute exposure to xenobiotics. Therefore, future research in the field could progress NPS hair analysis and aim the monitoring of NPS expansion and extent of use in the community.

Analysis of hair steroid hormone concentrations at different parts of the head by liquid chromatography-tandem mass spectrometry

BACKGROUND

Steroid hormones are known to be associated with diseases like androgenetic alopecia (AGA) resulting in hair loss. The lack of a detailed analysis of the local concentration of steroids in different parts of the head underlies the rationale and purpose of this study.

METHODS

To evaluate the concentration distributions of steroid hormones in hair in different parts of the head, hair samples of 8 healthy men from 9 point-areas covering the frontal, parietal, and occipital regions were collected. Eight steroid hormones were measured by using the LC-MS/MS and region-wise comparison for different hormones was done using the mean z-score and Tukey's HSD.

RESULTS

Five of the 8 hormones had a high concentration in the parietal region, with dihydrotestosterone (DHT) showing a peak in the central parietal region (z = 1.59) suggesting a correlation with AGA's clinical presentation. Whereas, no significant differences were observed for testosterone and cortisol between the parietal and occipital regions. Higher DHT levels at the parietal region were also verified with a small group of AGA patients.

CONCLUSIONS

This research expands upon the role of steroid hormones in hair follicle tissue elucidating their relationship with disease, thus contributing to disease management.

Homicidal poisoning series in a nursing home: retrospective toxicological investigations in bone marrow and hair

Homicidal poisonings remain rare and can be difficult to detect, especially in the elderly or in medical settings. In this atypical poisoning series, a young nursing assistant purposely poisoned thirteen residents of a nursing home and killed ten of them. The medications used were a mix of psychotropic medications (cyamemazine, loxapine, tiapride, risperidone, and mirtazapine), under liquid formulation, which were inducing malaise and coma. The forensic investigation included analysis of blood, urine, hair, and bone marrow and exhumations of seven corpses up to 3 years after the inhumation. Hair collected from a hairbrush of a cremated victim have been analyzed. Bone marrow sample preparation was based on a liquid/liquid triple extraction. Hair were incubated after decontamination overnight at 55 °C in methanol. Segmentation was possible for seven samples, except for delayed exhumation samples (n = 4) and hairbrush hair sample (n = 1). The extracts were then analyzed using gas chromatography coupled with mass spectrometry (GC-MS) for unknown screening and using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for a targeted screening and quantification. Screenings revealed the presence of the same mix of psychotropic medications. Cyamemazine, mirtazapine, loxapine, tiapride, and risperidone hair concentrations were 6-17,458 pg/mg, 74-1271 pg/mg, 9-1346 pg/mg, 13-148 pg/mg, and 3-5 pg/mg, respectively. Cyamemazine bone marrow concentrations were 229 and 681 ng/g and 152-717 ng/mL in blood. Patients' medications were also identified and quantified. This poisoning series provide analytical data that could support subsequent toxicological result interpretation in similar forensic cases.

A comprehensive UHPLC-MS/MS screening method for the analysis of 98 New Psychoactive Substances and related compounds in human hair

In this study, a rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the targeted analysis of 98 New Psychoactive Substances (NPS) from the hair matrix. The monitored compounds included various chemical classes (7 phenethylamines, 10 tryptamines, 18 cathinones, 24 synthetic opioids, and 38 synthetic cannabinoids) with emphasis given to newly emerged NPS. The method employed a direct extraction process through the incubation of hair samples (25 mg) and internal standards with M3® reagent at 100 °C for 60 min, followed by extract purification through acid and basic liquid-liquid micro-extraction (LLME). Extracted compounds were analyzed through LC-MS/MS system operating in multiple reaction monitoring mode. NPS were separated in 9.5 min with a Poroshell 120 EC-C18 column (2.7 μm, 4.6 × 50 mm) using a gradient eluting mobile phase composed of water and acetonitrile/water (95:5) both containing 0.1 % of formic acid. The developed and validated method shows a good precision (≤ 15 %), linearity (R² between 0.993 and 0.999), selectivity, and sensitivity (LOD: 0.6-10.3 pg mg^-1 and LOQ: 2.1-34.4 pg mg^-1). The method showed also reduced matrix effect and acceptable recovery for most of the targeted compounds. Our results showed that this method is suitable for quantifying NPS in hair matrix and could be employed in the context of routine analyses in analytical laboratories.

Population-based biomonitoring of exposure to persistent and non-persistent organic pollutants in the Grand Duchy of Luxembourg: Results from hair analysis

Environmental exposure of humans to pollutants has been associated with adverse health outcomes, but few studies have evaluated the multiple exposure of general populations. In the present study, we used hair analysis to assess the exposure of a general adult population (n = 497) in Luxembourg to 34 persistent and 33 non-persistent organic pollutants from 11 chemical families, such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), and pyrethroid pesticides (PYRs). We detected 24 persistent and 29 non-persistent organic pollutants, with 17 pollutants being detected in more than 50% of hair samples. The median concentrations for pollutants detected in 100% of the samples were 0.37 pg/mg for lindane (γ-HCH), 0.15 pg/mg for hexachlorobenzene (HCB), 14.1 pg/mg for p-nitrophenyl (PNP), and 0.10 pg/mg for trifluralin. Each participant in this study had detectable levels of at least 10 of the pollutants analyzed, and 50% of participants had 19 or more, suggesting the simultaneous exposure to numerous different pollutants among our study population. Significant correlations were often found between pollutants from the same family, with the strongest being found between two PYR metabolites, trans/cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-carboxylic acid (Cl₂CA) and 3-phenoxybenzoic acid (3-PBA). Results from multiple linear regression analyses showed that sex, age and/or body mass index were significantly associated with 15 out of the 17 frequently detected pollutants. The current study is the first nationwide biomonitoring investigating organic contaminants in the Luxembourg population using hair analysis.

Ocfentanil testing in hair from a fatality case: Comparative analysis of a lock of hair versus a single hair fiber

In clinical and forensic toxicology, hair analysis offers a larger window for detecting drug exposure than blood or urine. Drug measurements are generally carried out using a segmented lock of hair, but few articles report the use of a single hair to document drug exposure. Nevertheless, single hair analysis can be very useful, particularly if only small amounts of biological matrices are available. More data on analyzing new synthetic opioids (NSOs) in hair are needed to help interpretation in future cases. In this study, segmental single hair analysis is compared with segmental hair lock analysis to document an ocfentanil-related death. The hair lock and single hair analyses were performed using the LC-MS/MS method after decontamination and incubation. Ocfentanil (OcF) concentrations ranged from 42 to 150 pg/mg in the segmented hair lock, depending on the segments. The hair lock and single hair analyses showed similar results: the highest concentrations were measured in the first two centimeters and decreased from root to tip. The similar profiles obtained from both the lock of hair and the single hair demonstrate the relevance of single hair analysis in cases where very few data are available. This article describes OcF concentrations in an authentic hair sample after a documented intake of this molecule in a fatality.

Diagnostic challenges, best sources, and future paths for diagnoses of Beethoven's physical and mental illnesses

Significant problems have plagued medical and musicological researchers who wish to understand the complexities of Beethoven's physical and mental health. The most significant is a lack of detailed information on the composer's medical and mental conditions as they appeared and progressed. Though he consistently saw well-regarded doctors from around 1800 to his death, only one wrote a detailed description and only a few left information in the conversation books. Other problems are the limited medical knowledge about certain diseases at the time (such as the causes of deafness) and treatments with no or limited effectiveness (both for deafness and liver disease, for instance). Two additional problems are the focus of this essay. The first is the fact that studying the composer's health and diseases is a cross-disciplinary endeavor that requires specialized knowledge both of medical science and of musicological expertise into every corner of Beethoven's biography. The second concerns acquiring a knowledge of all the available sources that have survived to document the composer's health and a critical assessment of their value.

Incorporation of five common hypnotics into hair after a single dose and application to a forensic case of drug facilitated crimes

In order to obtain fundamental information on the disposition of hypnotics into hair after a single oral dose the quantitative hair analysis of triazolam (TZ), etizolam (EZ), flunitrazepam (FNZ), nitrazepam (NZ) and zolpidem (ZP) have been performed using a validated LC-MS/MS procedure. Hair specimens (straight, black) were collected from three subjects about one month and three months after a single 0.25 mg dose of TZ, 1 mg of EZ, 2 mg of FNZ, 5 mg of NZ and 10 mg of ZP tartrate. The subjects ingested just one out of five different hypnotics on each day, each of five days in turn. All ingested hypnotics have been detected in hair from each subject both one month and three months after intake, and their concentrations were in the range of 0.023-0.043 pg/hair strand (0.077-0.36 pg/mg) for TZ, 0.11-0.63 pg/hair strand (0.44-5.2 pg/mg) for EZ, 0.14-2.6 pg/hair strand (0.56-22 pg/mg) for FNZ, 0.33-1.7 pg/hair strand (1.3-17 pg/mg) for NZ and 20-40 pg/hair strand (120-270 pg/mg) for ZP. For FNZ and NZ, not only the parent drugs but also their metabolites, 7-amino-FNZ and 7-amino-NZ, were detected in the range of 2.3-9.2 pg/hair strand (9.2-82 pg/mg) and 2.4-9.1 pg/hair strand (8.0-55 pg/mg), respectively. The calculated incorporation ratios into hair against the dose were found to exhibit similarity between the four benzodiazepines. This finding suggests the ability to apply these quantitative data to approximately estimating the amounts of other benzodiazepines, which have similar chemical structures, in hair although it should be noted that the amounts of drugs in hair varies considerably depending on the hair color. On the other hand, the incorporation ratio of ZP showed 15-29 times higher than that of TZ, indicating that lipophilic ZP was more likely to incorporate into hair than benzodiazepines. In addition, the application of the present data to a drug-facilitated sexual assault was shown.

LC-MS/MS method for determining picogram-level of zolpidem and its main metabolites in hair using a zirconia-based sorbent

Although urine and blood samples have been conventionally used for testing zolpidem (ZPD), a sedative-hypnotic, these matrices have limited application because they have a relatively short detection period and can be used only in case of recent drug exposure. Therefore, it is necessary to use an alternative biological sample to obtain the evidence of ZPD misuse. Herein, a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of ZPD and its metabolites, zolpidem phenyl-4-carboxylic acid (ZPCA) and zolpidem 6-carboxylic acid (ZCA), in hair to resolve the above-mentioned problems. Mechanical pulverization of hair, methanol extraction with sonication, and the zirconia-based hybrid solid-phase extraction technique were used for obtaining improved extraction efficiency and effective sample purification. The treated hair sample was analyzed using the LC-MS/MS method with the electrospray ionization source in positive and multiple-reaction monitoring modes. The target analytes were separated and detected within 8 min using an Xselect HSS T3 column. Gradient elution was performed using 5 mM ammonium formate and acetonitrile. The lower limit of quantification of ZPD, ZPCA, and ZCA were 1.0, 0.5, and 1.0 pg mg^-1, respectively. The calibration ranges were 1.0-1000.0 pg mg^-1 for ZPD, 0.5-200.0 pg mg^-1 for ZPCA, and 1.0-200.0 pg mg^-1 for ZCA, with the determination coefficients (r² ≥ 0.9986). The intraday accuracy and precision ranged from -7.1 to 9.0% and within 6.5%, respectively, and the interday accuracy and precision ranged from -6.1 to 7.9% and within 5.4%, respectively. The recovery, matrix effect, and process efficiency were 65.2-96.6%, 64.6-106.5%, and 44.3-100.5%, respectively, with the relative standard deviation of 4.0-5.0%. The developed method was successfully applied to analyze 13 forensic hair samples of ZPD abusers, and the concentration ratios of ZPD and its two main metabolites (ZPCA and ZCA) in the ZPD-positive samples were also presented. These results revealed that ZPCA and ZCA were not easily incorporated into hair, and demonstrated that their analysis in hair samples requires the employed method to have picogram-level sensitivity. Therefore, the developed method was suitable for simultaneous analysis of ZPD, ZPCA, and ZCA in hair samples, and it could provide clear evidence for illegal ZPD administration, including ZPD-facilitated sexual assault.

A case report on fatal intoxication by tapentadol: Study of distribution and metabolism

We report a case in which a tapentadol acute intoxication was suspected as the cause of death of a 39-year-old man: approximately two days after death, cardiac and femoral blood, as well as urine, bile, gastric content and chest hair, were collected during the autopsy. Tapentadol was detected before and after hydrolysis in femoral (530 ng/mL unconjugated and 1570 ng/mL conjugated) and cardiac (680 ng/mL unconjugated and 3440 ng/mL conjugated) blood, and additionally in bile (3200 ng/mL), urine (9300 ng/mL), chest hair (2850 pg/mg) and gastric content. LC-QTOF screening analysis confirmed the presence of five different tapentadol metabolites (tapentadol-O-glucuronide, tapentadol-O-sulfate, N-desmethyltapentadol, N-desmethyltapentadol-glucuronide and N-desmethyltapentadol-O-sulfate), in urine, bile, cardiac and femoral blood. Positivity of body hairs allowed us to conclude that the man had used tapentadol in the last weeks/months. Autopsy and toxicological results (also positive for clotiapine, diazepam and chlordesmethyldiazepam) suggested that tapentadol could have caused, even at low concentrations, a severe respiratory depression, which contributed to the death of the subject. This is one of the few cases in literature where tapentadol was detected in blood, together with its metabolites, and the only one in which the parent drug was identified in hairs.

Analysis of 28 hair samples from users of the hallucinogenic beverage ayahuasca

Ayahuasca is a psychoactive beverage widely used in religious ceremonies in Amazonia. Dimethyltryptamine is the main active compound of ayahuasca. Dimethyltryptamine has many hazardous effects, including hallucinations. In the present study, a fast and reliable UPLC-MS/MS method was developed and validated for the quantitation of dimethyltryptamine in hair samples. Twenty-milligram hair samples were pulverized with methanol below 4 °C. After ultrasonication, centrifugation and filtration, 200 μL of supernatant was placed into an autosampler vial for LC-MS/MS analysis. The lower limit of quantitation (LLOQ) was 3 pg/mg. The resulting calibration curve for dimethyltryptamine fit the expression y = 281.50213x + 0.00231 (R2 = 0.992). Acceptable intraday and interday precision (RSD < 15%) and accuracy (92-113%) were achieved. The dilution integrity was deemed acceptable based on accuracy (96%) and precision (1.8%). The validated method was successfully applied to 28 forensic cases. The concentrations of dimethyltryptamine ranged from 3 to 1109 pg/mg.

Hair endocannabinoid concentrations in individuals with acute and weight-recovered anorexia nervosa

BACKGROUND

The endocannabinoid system has been suggested to modulate energy metabolism and stress response and could be an important factor in the pathophysiology of anorexia nervosa (AN). In the context of AN, excessive physical activity may influence endocannabinoid concentrations. The objective of this study was to investigate hair endocannabinoid concentrations at different stages of the disorder. Measurement in hair allows for a cumulative assessment of endocannabinoid concentrations independent of circadian rhythms.

METHODS

In a combined cross-sectional and longitudinal design, we measured hair concentrations of the endocannabinoids anandamide and 2-arachidonoylglycerol and the endocannabinoid-related compounds palmitoylethanolamide, oleoylethanolamide, and stearoylethanolamide in female underweight patients with acute AN (n = 67, reassessment of n = 47 after short-term weight restoration with a body mass index increase of at least 14%), individuals long-term recovered from AN (n = 27), and healthy control participants (n = 84).

RESULTS

Hair concentrations of anandamide and all endocannabinoid-related compounds were elevated in acute AN and decreased over the course of short-term weight restoration. Anandamide concentrations remained elevated in long-term recovered AN patients. In long-term recovered patients, physical activity correlated positively with the concentrations of all endocannabinoid-related compounds.

CONCLUSION

The current study provides evidence for a significant alteration of the endocannabinoid system in acute AN, which may partly persist into long-term recovery. The endocannabinoid system may be a possible target for pharmaceutical interventions in AN, which should be explored in further preclinical and subsequently clinical randomized controlled trials.

Beethoven's death-the result of medical malpractice?

Two different strands of hair taken from Beethoven’s head after his death were examined for heavy metals using scanning electron microscopy (SEM) and laser ablation-ICP-MS (inductively coupled plasma–mass spectroscopy). The results revealed the presence of small lead particles on the surface of Beethoven’s hairs and fluctuating lead levels in hair medulla along the length of the hair due to alternating lead exposure, with an average lead exposure of 100 times the normal value. The time-line attached to the peaks of these fluctuating values correlate with the pneumonia treatment and the paracenteses performed, including the subsequent treatment of the procedure wounds. While the administration of lead-containing drugs and treatments had been proven to resolve the pneumonia, it had simultaneously caused massive liver failure, accelerated by pre-existing cirrhosis. The question as to whether Beethoven’s death was a case of malpractice can only be answered from a forensic point of view ex ante, since the state of the medical knowledge of the time has to be taken into account.

Comparison of polymerases used for amplification of mitochondrial DNA from challenging hairs and hairs of various treatments

Forensic DNA analysis of hair evidence typically involves the amplification and sequencing of the control region (CR) of the mitochondrial genome (mtgenome). In compromised hair samples, such as shed hairs, the number of mtgenome copies could be low; thus, it is imperative that the polymerase used in PCR is efficient to ensure maximum amplification. Considering this, the first phase of this study compared the yields obtained from 12 polymerases (sourced from a range of commercial companies) when amplifying the CR, hypervariable (HV) region II (HV2), and hypervariable subregion II-B (HV2B). This initial assessment was performed using mitochondrial DNA (mtDNA) extracted from 2 cm of hair adjacent to the root from three donors of different self-reported ancestries and hair color/texture. PrimeSTAR HS and KAPA HiFi HotStart consistently generated significantly higher amplicon yields (p < 0.05, ~5-fold increase) for most regions than AmpliTaq Gold DNA polymerase (the polymerase validated for use in most forensic laboratories). The second phase of this project was focused on assessing the broad utility of these top two performing polymerases for amplifying two regions of the mtgenome (CR and HV2B) from hair samples representing diverse self-reported ancestral origins (European, Latin American, African American, Asian, and Native American), characteristics/treatments (bleached, dyed, and chemically straightened), and anatomical origins (e.g., head and pubic region) (n = 41). These regions were chosen as they are the most challenging to amplify and sequence in compromised hair samples due to length (i.e., the CR is ~1.2 kb) and repeat structure (i.e., the polycytosine stretch within HV2B). The results indicated that regardless of sample type, PrimeSTAR HS and KAPA HiFi HotStart polymerases outperformed (p < 0.05) AmpliTaq Gold DNA polymerase (averaging 11- and 8-fold increased yields, respectively). The results from this study highlight that enhanced commercially available polymerases appear to significantly improve the amplification of mtDNA from challenging hair samples.

Pharmacokinetic study of midazolam and α-hydroxymidazolam in guinea pig blood and hair roots after a single dose of midazolam

The appearance of midazolam (M) and its metabolites into the hair root following a single administration was examined by following the time course of M and α-hydroxymidazolam (αHM) in hair roots and blood from guinea pigs. The back hair of guinea pigs was shaved before drug administration and before each sampling, and hair roots (3-5 mm) were plucked at 5, 15, and 30 min, 1, 2, 4, 6, 10, 24, 48, 72, 96, 120, 144 h, and 7, 14, 21, and 28 days. The kinetic parameters of M and αHM in guinea pig blood and hair roots were determined for three doses (5, 10, and 25 mg/kg). Comparisons of drug time course between hair roots and blood indicated an association between drug concentrations in the hair root and the blood. M and αHM entered the hair root within 5 min after a single exposure. The detection windows were also longer for the hair root than for the blood. Consequently, the hair root can be a valuable specimen in acute poisonings or drug-facilitated crime (DFC) cases, if other matrices are unavailable, or if blood and urine results are negative. Hair shafts (with hair roots) were plucked at 28 days and segmented. The concentrations of M and αHM were lower in the hair shafts than in the hair roots. The concentrations of the metabolite αHM in hair shafts were barely detectable. The concentrations of M and αHM in the hair root showed a moderate correlation with dose. Comparison of drug levels in hair roots between the washed group and the unwashed group indicated a generally stable percentage between the washed and unwashed groups of 40-60 % during the entire time course. This indicates that drugs are likely to be immobilized in the hair root at the beginning of the incorporation process.

Development and validation of a liquid chromatography-tandem mass spectrometry method for quantifying delamanid and its metabolite in small hair samples

New all-oral regimens for rifampin-resistant tuberculosis (RR-TB) are being scaled up globally. Measurement of drug concentrations in hair assesses long-term drug exposure. Delamanid (DLM) is likely to be a key component of future RR-TB treatment regimens, but a method to describe its quantification in hair via liquid chromatography-tandem mass spectrometry (LC-MS/MS) has not previously been described. We developed and validated a simple, fast, sensitive, and accurate LC-MS/MS method for quantifying DLM and its metabolite DM-6705 in small hair samples. We pulverized and extracted two milligrams of hair in methanol at 37 °C for two hours, and diluted 1:1 with water. A gradient elution method eluted DLM, DM-6705, and the internal standard OPC 14714 within 3 min, bringing overall analysis time to 5.5 min. The method has limits of detection (LOD) of 0.0003 ng/mg for DLM and 0.003 ng/mg for DM-6705. The established linear dynamic ranges are 0.003-2.1 ng/mg and 0.03-21 ng/mg for DLM and DM-6705, respectively. Eleven of 12 participant hair samples had concentrations within DLM's linear dynamic range, while all 12 samples had concentrations within the quantifiable range for DM-6705. The ranges of concentrations observed in these clinical samples for DLM and DM-6705 were 0.004-0.264 ng/mg hair and 0.412-12.041 ng/mg hair respectively. We demonstrate that while DLM was detected in hair at very low levels, its primary metabolite DM-6705 had levels approximately 100 times higher. Measuring DM-6705 in hair may accurately reflect long-term adherence to DLM-containing regimens for drug-resistant TB.