Ethyl glucuronide determination in meconium and hair by hydrophilic interaction liquid chromatography–tandem mass spectrometry

The complementarity of phosphatidylethanol in whole blood and ethyl glucuronide in hair as biomarkers for the monitoring of alcohol use

Monitoring long-term alcohol use and/or abstinence is essential in clinical and medico-legal cases. Analysis of ethyl glucuronide (EtG) in hair provides information on alcohol consumption over several months. However, there is a lag time between ethanol consumption, incorporation of EtG in the hair bulb and hair growing out of the scalp. Phosphatidylethanol (PEth) 16:0/18:1 analysis in whole blood has a detection window of 2-4 weeks, allowing for the detection of recent alcohol consumption. In this study, 2340 paired samples (of hair and venous whole blood from 1170 individuals) were analysed for EtG in hair (hEtG) and PEth 16:0/18:1 in venous whole blood. PEth 16:0/18:1 and hEtG results were subdivided into three categories according to the consensus of SoHT (hEtG) and PEth-NET (PEth): abstinence/low, moderate or excessive alcohol consumption. For hEtG analysis, 446 individuals presented abstinence/low alcohol consumption, of which 2% were classified as excessive alcohol users through PEth 16:0/18:1 analysis. This suggests excessive alcohol consumption in the weeks before sample collection. Out of 483 individuals classified as heavy alcohol users based on hEtG analysis, 14% showed abstinence/low alcohol consumption for PEth 16:0/18:1 analysis, implying that these subjects stopped drinking 2-4 weeks before sample collection. Our results show that the analysis of the two different biomarkers can lead to a more accurate categorisation of individuals. Therefore, we emphasize that for the retrospective investigation of alcohol use, it is necessary to include two alcohol use biomarkers with different detection windows.

PTCA (1-H-Pyrrole-2,3,5-Tricarboxylic Acid) as a Marker for Oxidative Hair Treatment: Distribution, Gender Aspects, Correlation with EtG and Self-Reports

Hair analysis is an important and reliable resource for the assessment of alcohol or drug abstinence in both clinical and forensic toxicology. Recently, it has been demonstrated that hair oxidative cosmetic treatments lead to the reduction in incorporated xenobiotics in hair, such as ethyl glucuronide (EtG), a marker of alcohol abuse, and the formation of 1-H-pyrrole-2,3,5-tricarboxylic acid (PTCA), a degradation product of melanin. The aim of the present study was to investigate PTCA trends in a large number of samples in order to evaluate the reliability of this biomarker in recognizing previous cosmetic treatment in forensic analyses. Therefore, a single-step extraction followed by an high-performance liquid chromatography--tandem mass spectrometry (HPLC--MS-MS) method was established and validated for the simultaneous determination of EtG and PTCA. This method was applied to 1,219 scalp hair samples from two groups, namely self-reported untreated and in vivo treated hair, exhibiting a concentration range of 6.7 to 440.0 pg/mg for EtG (mean 26.8 pg/mg, median 14.6 pg/mg) and 0.009 to 49.8 ng/mg for PTCA (mean 0.66 ng/mg, median 0.02 ng/mg). The PTCA content was significantly different among the two experimental groups, with the in vivo treated group showing significantly higher levels of PTCA than the untreated group. Finally, an in vitro bleaching was performed and the results confirmed that a strong hair oxidative treatment may negatively affect EtG test results (false negative), whereas the mean PTCA content increased showing statistically significant differences between untreated and in vitro oxidative treated samples. The present study suggests that the determination of PTCA in routine hair analysis procedure could be useful in order to discover previous cosmetic treatment including oxidation.

Development and validation of a method for the simultaneous analysis of fatty acid ethyl esters, ethyl sulfate and ethyl glucuronide in neonatal meconium: application in two cases of alcohol consumption during pregnancy

Alcohol consumption during pregnancy constitutes one of the leading preventable causes of birth defects and neurodevelopmental disorders in the exposed children. Fatty acid ethyl esters (FAEEs), ethyl glucuronide (EtG) and ethyl sulfate (EtS) have been studied as potential biomarkers of alcohol consumption. However, most analytical approaches proposed for their analysis in meconium samples consist of separated extraction procedures requiring the use of two meconium aliquots, which is costly in terms of both time and materials. Therefore, the aim of this study was to develop and validate a method for the simultaneous extraction of 9 FAEEs, EtG and EtS from one meconium aliquot. The sample was homogenized using methanol, and then FAEEs were extracted with hexane while EtG and EtS were isolated using acetonitrile. Then, extracts were applied to solid-phase extraction columns and analysed by gas chromatography mass spectrometry (FAEEs) and liquid chromatography tandem mass spectrometry (EtG and EtS). Calibration curves were linear with r values greater than 0.99. The LODs ranged from 0.8 to 7.5 ng/g for FAEEs and were 0.2 ng/g and 0.8 ng/g for EtS and EtG, respectively. LOQs ranged from 5 to 25 ng/g for FAEEs and were 1 ng/g and 2.5 ng/g for EtS and EtG, respectively. Accuracies and precisions were between 93.8 and 107% and between 3.5 and 9.7%, respectively. The recovery values ranged from 89.1 to 109%. The method proved to be sensitive, specific, simple and fast and allowed for the reduction of the amount of organic solvent used for extraction compared to other published data while higher recoveries were obtained. The method was used for analysis of meconium samples in two cases of mothers who were consuming alcohol during pregnancy.

Evaluation and review of ways to differentiate sources of ethanol in postmortem blood

Accurate determination of a person's blood alcohol concentration (BAC) is an important task in forensic toxicology laboratories because of the existence of statutory limits for driving a motor vehicle and workplace alcohol testing regulations. However, making a correct interpretation of the BAC determined in postmortem (PM) specimens is complicated, owing to the possibility that ethanol was produced in the body after death by the action of various micro-organisms (e.g., Candida species) and fermentation processes. This article reviews various ways to establish the source of ethanol in PM blood, including collection and analysis of alternative specimens (e.g., bile, vitreous humor (VH), and bladder urine), the identification of non-oxidative metabolites of ethanol, ethyl glucuronide (EtG) and ethyl sulfate (EtS), the urinary metabolites of serotonin (5-HTOL/5-HIAA), and identification of n-propanol and n-butanol in blood, which are known putrefaction products. Practical utility of the various biomarkers including specificity and stability is discussed.

Determination of ethyl glucuronide in human hair samples: Decontamination vs extraction

Decontamination of samples prior to analysis is common practice and recommended for ethyl glucuronide (EtG) hair testing. The aim of this study was to evaluate the applied decontamination procedure during routine hair EtG analysis by monitoring the ethyl glucuronide concentrations in the washing solutions from a representative cohort of individual hair samples. Hair samples from 150 individuals were tested for hair EtG by a validated routine procedure (liquid chromatography/tandem mass spectrometry). A four-step decontamination procedure (ethanol, water, acetone, dichloromethane) was applied to all samples prior to analysis. Hair samples from 20 individuals were analyzed along with the complete set of individual washing solutions. Hair samples from an additional 130 individuals were analyzed along with the corresponding aqueous wash fraction only. No EtG was detected in the washing solutions from hair samples that tested negative for EtG (n = 42). Hair samples positive for ethyl glucuronide (n = 108) were found to liberate different amounts of EtG during decontamination: whereas no, or low portions of, EtG (< 10% of extracted hair EtG) were found in the corresponding washing solutions of the majority (n = 91) of individual samples, there was a minority of samples (n = 6) with more than half of the extracted hair EtG present in the decontamination solvent. No correlation of the decontaminated amount of EtG and the extracted hair EtG was observed. Further experimental studies are necessary to investigate if the observed easily removable fraction of EtG is associated with external contamination and if analysis of wash solutions could be helpful for identifying external contamination in hair testing for ethyl glucuronide.

Sensitive and reliable gas chromatography tandem mass spectrometry assay for ethyl glucuronide in neonatal meconium

Prenatal exposure to maternal ethanol leads to serious physical and mental irreversible disabilities. Ethyl glucuronide (EtG) is a direct metabolite of alcohol and its measurement in neonatal meconium has been established as the best biomarker to assess prenatal exposure to social and excessive gestational ethanol. We developed and validated the first gas chromatography tandem mass spectrometry method to quantify EtG extracted from meconium by a simple solid phase extraction pretreatment. The method was linear from limit of quantification (2 ng/g) to 200 ng/g matrix with good determination coefficient (r² = 0.99). Recovery of EtG from meconium was always higher than 70% and intra-assay and inter-assay precision and accuracy were always better than 10%. Robustness of the developed GC-MS/MS method was tested by analysing 150 real samples coming from a previous national epidemiological project pre-screened through an ultra-chromatography tandem mass spectrometry assay obtaining a good comparability of results obtained by the two methods.

Ethyl glucuronide hair testing: A review

Ethyl glucuronide (EtG) is a minor, non-oxidative ethanol metabolite that can be detected in several matrices (e.g. blood, urine, hair, meconium) for variable periods of time. Quantification of EtG in hair (hEtG) has established itself, over recent years, as one of the most reliable biomarkers of long-term alcohol consumption habits, with the Society of Hair Testing (SoHT) offering cut-off values for assessment of both abstinence and heavy drinking (>60 g/day). Despite its high diagnostic performance, however, issues concerning inter- and intra-laboratory variability as well as data interpretation are still being investigated and represent the ultimate barrier to widespread acceptance of hEtG in the forensic context. The aim of this review is to summarize currently available analytical methods of hEtG testing, provide a framework to understand current hEtG cut-offs and their possible upcoming changes (in particular, a lower abstinence cut-off has been proposed for the 2019 revision of the SoHT consensus), and offer a schematic but exhaustive overview of the pitfalls in result reproducibility and interpretation that may limit applications of hEtG testing in the forensic context. Ultimately, the purpose of the authors is not to undermine the reliability of hEtG as an alcohol use marker, but rather to enhance it by promoting familiarization with all aspects related to it, from ethanol pharmacokinetics and EtG incorporation into hair, to sample preparation and analytical methods, to specific cases warranting close attention and additional tests for correct interpretation of hEtG results.

Monitoring people at risk of drinking by a rapid urinary ethyl glucuronide test

Alcohol and illicit drug abuse are major public health problems worldwide. Since alcohol is the predominant substance of choice in polydrug abusers, monitoring its use, along with urinary drug screening in patients in rehabilitation programs, appeared to be crucial in identifying patients at risk of alcohol disorders leading to impaired quality of life. Ethyl β-D-6-glucuronide, a non-oxidative, non-volatile, stable and minor direct ethanol metabolite, has a 6h to 4 day window of detection in urine after the last alcohol intake. Each of the 119 subjects (85 males, 34 females) registered with the Public Health Service for Drug Dependence Treatment provided a urine sample for ethylglucoronide (EtG) determination in an immunochemical test with a 500 ng/ml cutoff. All results were evaluated with confirmation criteria of a fully validated gas chromatography/mass spectrometry assay. The diagnostic performance of the EtG immunochemical test was assessed using Receiver Operating Characteristic Curve analysis. The immunochemical test specificity was 100% for EtG urinary values above 500 ng/ml. No false positive results were found. With levels below 500 ng/ml, 12% of the samples were classified as negative. The average consumption of the incorrectly classified subjects was 171 ng/ml, with a misclassification error of 6.5% to 18.5%. High agreement between EtG as determined in an immunochemical test and gas chromatography/mass spectrometry, suggests that the rapid EtG test is a reliable, cost-effective alcohol monitoring assay for patient management in many non-forensic settings, such as drug rehabilitation programs.

Ethyl linolenate is elevated in meconium of very-low-birth-weight neonates exposed to alcohol in utero

BACKGROUND

The health implications of in utero alcohol exposure have been difficult to study in very-low-birth-weight newborns (VLBW) because of an inability to identify maternal alcohol exposure. Fatty acid ethyl esters (FAEEs) are elevated in meconium of alcohol-exposed term newborns. We hypothesized that meconium FAEEs would be similarly elevated in alcohol-exposed VLBW premature newborns.

METHODS

In a retrospective cohort study of 64 VLBW neonates, newborns were classified into Non-Exposed, Any Exposure, or Weekly Exposure groups based on an in-depth structured maternal interview. Meconium FAEE concentrations were quantified via gas chromatography mass spectrometry.

RESULTS

Alcohol exposure during Trimester 1 (Any Exposure) occurred in ~30% of the pregnancies, while 11% of the subjects reported drinking ≥ 1 drink/week (Weekly Exposure). Meconium ethyl linolenate was higher in Any Exposure (P = 0.01) and Weekly Exposure groups (P = 0.005) compared to the Non-Exposed VLBW group. There was a significant positive correlation between Trimester 1 drinking amounts and the concentration of meconium ethyl linolenate (P = 0.005). Adjusted receiver operating characteristic (ROC) curves evaluating ethyl linolenate to identify alcohol-exposed VLBW newborns generated areas under the curve of 88% with sensitivities of 86-89% and specificities of 83-88%.

CONCLUSION

Despite prematurity, meconium FAEEs hold promise to identify the alcohol-exposed VLBW newborn.

Simultaneous determination of ethanol's four types of non-oxidative metabolites in human whole blood by liquid chromatography tandem mass spectrometry

The importance of ethanol non-oxidative metabolites as the specific biomarkers of alcohol consumption in clinical and forensic settings is increasingly acknowledged. Simultaneous determination of these metabolites can provide a wealth of information like drinking habit and history, but it was difficult to achieve because of their wide range of polarity. This work describes development and validation of a simple liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for 4 types of ethanol non-oxidative metabolites (ethyl glucuronide, ethyl sulfate, fatty acid ethyl esters and phosphatidylethanols) in 50 μL of human whole blood. Pretreatment method, column and MS conditions were optimized. For the first time, the four types of ethanol non-oxidative metabolites with enormous discrepancies of property were simultaneously extracted and analyzed in one run within 40 min. The limits of detections (LODs) were among 0.1-10 ng/mL, and good linearity was obtained. Deviations in precision and accuracy were all lower than 15% at three QC levels. This method was then applied to two forensic samples, resulting in information on drinking habits and drinking time which were very useful for the interpretation of the blood alcohol results.

Biomarkers for the Detection of Prenatal Alcohol Exposure: A Review

Alcohol exposure during pregnancy can cause adverse effects to the fetus, because it interferes with fetal development, leading to later physical and mental impairment. The most common clinical tool to determine fetal alcohol exposure is maternal self-reporting. However, a more objective and useful method is based on the use of biomarkers in biological specimens alone or in combination with maternal self-reporting. This review reports on clinically relevant biomarkers for detection of prenatal alcohol exposure (PAE). A systematic search was performed to ensure a proper overview in existing literature. Studies were selected to give an overview on clinically relevant neonatal and maternal biomarkers. The direct biomarkers fatty acid ethyl esters (FAEEs), ethyl glucuronide (EtG), ethyl sulfate, and phosphatidylethanol (PEth) were found to be the most appropriate biomarkers in relation to detection of PAE. To review each biomarker in a clinical context, we have compared the advantages and disadvantages of each biomarker, in relation to its window of detectability, ease of collection, and the ease and cost of analysis of each biomarker. The biomarkers PEth, FAEEs, and EtG were found to be applicable for detection of even low levels of alcohol exposure. Meconium is an accessible matrix for determination of FAEEs and EtG, and blood an accessible matrix for determination of PEth.

Alternative sampling strategies for the assessment of alcohol intake of living persons

Monitoring of alcohol consumption by living persons takes place in various contexts, amongst which workplace drug testing, driving under the influence of alcohol, driving licence regranting programs, alcohol withdrawal treatment, diagnosis of acute intoxication or fetal alcohol ingestion. The matrices that are mostly used today include blood, breath and urine. The aim of this review is to present alternative sampling strategies that allow monitoring of the alcohol consumption in living subjects. Ethanol itself, indirect (carbohydrate deficient transferrin, CDT%) as well as direct biomarkers (ethyl glucuronide, EtG; ethyl sulphate, EtS; fatty acid ethyl esters, FAEEs and phosphatidylethanol species, PEths) of ethanol consumption will be considered. This review covers dried blood spots (CDT%, EtG/EtS, PEths), dried urine spots (EtG/EtS), sweat and skin surface lipids (ethanol, EtG, FAEEs), oral fluid (ethanol, EtG), exhaled breath (PEths), hair (EtG, FAEEs), nail (EtG), meconium (EtG/EtS, FAEEs), umbilical cord and placenta (EtG/EtS and PEth 16:0/18:1). Main results, issues and considerations specific to each matrix are reported. Details about sample preparation and analytical methods are not within the scope of this review.

Alcohol Consumption during Pregnancy: Analysis of Two Direct Metabolites of Ethanol in Meconium

Alcohol consumption in young women is a widespread habit that may continue during pregnancy and induce alterations in the fetus. We aimed to characterize prevalence of alcohol consumption in parturient women and to assess fetal ethanol exposure in their newborns by analyzing two direct metabolites of ethanol in meconium. This is a cross-sectional study performed in September 2011 and March 2012 in a series of women admitted to an obstetric unit following childbirth. During admission, socio-demographic and substance use (alcohol, tobacco, cannabis, cocaine, and opiates) during pregnancy were assessed using a structured questionnaire and clinical charts. We also recorded the characteristics of pregnancy, childbirth, and neonates. The meconium analysis was performed by liquid chromatography—tandem mass spectrometry (LC-MS/MS) to detect the presence of ethyl glucuronide (EtG) and ethyl sulfate (EtS). Fifty-one parturient and 52 neonates were included and 48 meconium samples were suitable for EtG and EtS detection. The median age of women was 30 years (interquartile range (IQR): 26–34 years); EtG was present in all meconium samples and median concentration of EtG was 67.9 ng/g (IQR: 36.0–110.6 ng/g). With respect to EtS, it was undetectable (<0.01 ng/g) in the majority of samples (79.1%). Only three (6%) women reported alcohol consumption during pregnancy in face-to-face interviews. However, prevalence of fetal exposure to alcohol through the detection of EtG and EtS was 4.2% and 16.7%, respectively. Prevention of alcohol consumption during pregnancy and the detection of substance use with markers of fetal exposure are essential components of maternal and child health.

A novel, simultaneous extraction of FAEE and EtG from meconium and analysis by LC-MS/MS

Fatty acid ethyl esters (FAEEs) and ethyl-glucuronide (EtG) in meconium have been widely studied as biomarkers of maternal alcohol consumption during pregnancy. Many analytical approaches have been proposed for their analysis, mostly consisting of separated extraction procedures requiring the use of two meconium aliquots. This study aimed to validate a new analytical procedure for the simultaneous extraction of FAEEs and EtG from a meconium aliquot through a single solid-phase extraction (SPE) applied to 242 anonymized samples of meconium. Targeted FAEEs were: ethyl-myristate (Myr), ethyl-palmitate (Pal), ethyl-oleate (Ole) and ethyl-stearate (Ste). Two hundred milligrams of meconium was sonicated with acetonitrile, and a single SPE performed by means of aminopropyl columns. FAEEs were eluted with hexane, followed by EtG elution with water. Both the mixtures were dried, recovered, and analyzed by liquid chromatography-tandem mass spectrometry using C8 (FAEEs) and C18 (EtG) columns. Transitions were: m/z 257 → 57,88, Myr; m/z 262 → 57,88, Myr-d5; m/z 285 → 57, 72, Pal; m/z 290 → 57,258, Pal-d5; m/z 311 → 72,114, Ole; m/z 316 → 72,265, Ole-d5; m/z 257 → 57,72 Ste; m/z 318 → 57,286, Ste-d5; m/z 221 → 75,85, EtG; m/z 226 → 75,85, EtG-d5. Lower limit of quantification range was 10-15 ng/g for FAEEs and 10 ng/g for EtG. Linearity was evaluated for different concentration ranges; the mean coefficients of determination (R (2)) were above 0.9961. Precision and accuracy for FAEEs and EtG were consistently ≤20 % and ±20 %, respectively. Ion suppression was observed for all the analytes. Matrix effect did not significantly affect the analyses. Recovery efficiency was 93 % for EtG and 75-85 % for FAEEs.

Bioanalytical procedures and developments in the determination of alcohol biomarkers in biological specimens

Excessive alcohol consumption is a global problem, and consequently its evaluation is of great clinical and forensic interest. Alcohol biomarkers have been the focus of several research works in the past decades, with new compounds being studied in more recent years. The main objective of this review is to discuss topics for an analyst to consider when evaluating alcohol consumption through the analysis of alcohol biomarkers in biological specimens. For this, existing alcohol biomarkers will be reviewed, including carbohydrate-deficient transferrin, 5-hydroxytryptophol, ethanol, hemoglobin-associated acetaldehyde, fatty acid ethyl esters, ethyl glucuronide, ethyl sulfate and phosphatidylethanol. Additionally, their potential will be discussed, as well as analytical considerations, main challenges, limitations, data interpretation and existing methodologies for their determination in biological specimens.

Bioanalysis during pregnancy: recent advances and novel sampling strategies

Consumption of drugs of abuse, tobacco and alcohol throughout pregnancy is a serious public health problem and results in an important economic cost to the health system. Drug and/or metabolites determination in biological matrices from mother and newborn is an objective measure of in utero drug exposure. We reviewed methods published for the determination of in utero drug exposure from 2007 to 2014, with special focus on meconium, placenta, umbilical cord and newborn hair. Accurate bioanalytical procedures are essential to obtain high-quality data to perform interventions and to establish correlations between analytical measures and clinical outcomes. We included a brief overview of clinical implications of in utero drug exposure to better understand the importance of this serious health issue.

Placental Fatty Acid ethyl esters are elevated with maternal alcohol use in pregnancies complicated by prematurity

The accumulation of fatty acid ethyl esters (FAEEs) in meconium of term newborns has been described as one potential biomarker of maternal alcohol use during pregnancy. FAEEs accumulate in multiple alcohol-exposed fetal tissues and in the placenta. Limited research has focused on the identification of the premature newborn exposed to alcohol in utero. We hypothesized that maternal alcohol use occurs in a significant proportion of premature deliveries and that this exposure can be detected as elevated placental FAEEs. The goals of this study were to 1) determine the prevalence of maternal alcohol use in the premature newborn and 2) investigate whether placental FAEEs could identify those newborns with fetal alcohol exposure. This prospective observational study evaluated 80 placentas from 80 women after premature delivery. Subjects were interviewed for alcohol intake and placental FAEEs were quantified via GC/MS. Receiver Operator Characteristic (ROC) Curves were generated to evaluate the ability of placental FAEEs to predict maternal drinking during pregnancy. Adjusted ROC curves were generated to adjust for gestational age, maternal smoking, and illicit drug use. 30% of the subjects admitted to drinking alcohol during pregnancy and approximately 14% answered questions indicative of problem drinking (designated AUDIT+). The specific FAEEs ethyl stearate and linoleate, as well as combinations of oleate + linoleate + linolenate (OLL) and of OLL + stearate, were significantly (p<0.05) elevated in placentas from AUDIT+ pregnancies. Adjusted ROC Curves generated areas under the curve ranging from 88–93% with negative predictive values of 97% for AUDIT+ pregnancies. We conclude that nearly one third of premature pregnancies were alcohol-exposed, and that elevated placental FAEEs hold great promise to accurately determine maternal alcohol use, particularly heavy use, in pregnancies complicated by premature delivery.

Development of a multi-residue method in a fetal matrix: analysis of meconium

Meconium is the earliest stool of newborns. It is a complex matrix that reflects the degree of fetal exposure to environmental pollutants. To investigate exposure to xenobiotics, an analytical method was developed to identify and quantify some pesticides and their metabolites and BTEX metabolites in meconium. Samples were prepared by two liquid-solid extractions and purified twice using SPE cartridges, followed by analysis with liquid chromatography coupled with tandem mass spectrometry. SPE cartridges (polymeric phase with hydrophilic and hydrophobic interactions, ion exchange, mixed mode) were tested and matrix effects were evaluated to determine purification performance. The quantification limits in meconium of this multi-residue method were in the range of 30 ng g(-1). The analytical method was applied to "real" meconium samples. Some target analytes were determined in most samples.

Validation of a novel method to identify in utero ethanol exposure: simultaneous meconium extraction of fatty acid ethyl esters, ethyl glucuronide, and ethyl sulfate followed by LC-MS/MS quantification

Presence of fatty acid ethyl esters (FAEE), ethyl glucuronide (EtG), and ethyl sulfate (EtS) in meconium, the first neonatal feces, identifies maternal alcohol consumption during pregnancy. Current meconium alcohol marker assays require separate analyses for FAEE and EtG/EtS. We describe development and validation of the first quantitative liquid chromatography tandem mass spectrometry assay for 9 FAEEs, EtG, and EtS in 100 mg meconium. For the first time, these alcohol markers are analyzed in the same meconium aliquot, enabling comparison of the efficiency of gestational ethanol exposure detection. 100 mg meconium was homogenized in methanol and centrifuged. The supernatant was divided, and applied to two different solid phase extraction columns for optimized analyte recovery. Limits of quantification for ethyl laurate, myristate, linolenate, palmitoleate, arachidonate, linoleate, palmitate, oleate, and stearate ranged from 25-50 ng/g, with calibration curves to 2,500-5,000 ng/g. EtG and EtS linear dynamic ranges were 5-1,000 and 2.5-500 ng/g, respectively. Mean bias and between-day imprecision were <15 %. Extraction efficiencies were 51.2-96.5 %. Matrix effects ranged from -84.7 to 16.0 %, but were compensated for by matched deuterated internal standards when available. All analytes were stable (within ±20 % change from baseline) in 3 authentic positive specimens, analyzed in triplicate, after 3 freeze/thaw cycles (-20 °C). Authentic EtG and EtS also were stable after 12 h at room temperature and 72 h at 4 °C; some FAEE showed instability under these conditions, although there was large inter-subject variability. This novel method accurately detects multiple alcohol meconium markers and enables comparison of markers for maternal alcohol consumption.

Hair ethyl glucuronide levels as a marker for alcohol use and abuse: a review of the current state of the art

BACKGROUND

Ethyl glucuronide (EtG) is a minor alcohol metabolite that has been proposed as a stable marker in hair to detect and quantify alcohol consumption over long time periods.

METHODS

We provide an outline of currently available techniques for EtG hair sample analysis and highlight the pitfalls related to data interpretation. The literature of EtG analysis has been reviewed from January 1980 up to August 2013. In addition, we present an overview of the clinical and forensic studies which have used EtG quantification in hair as a marker for alcohol consumption/abstinence and we provide suggestions for future research.

RESULTS

EtG is a stable marker in hair that can be used to detect and quantify alcohol consumption over long time periods. This alcohol metabolite remains in hair after complete elimination of alcohol. Currently, there are three main analytical techniques used to quantify EtG in hair: gas chromatography-mass spectrometry (GC-MS), gas chromatography-tandem mass spectrometry (GC-MS/MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS). No standardized protocols are yet available for the analysis of EtG levels in hair samples, and the current protocols vary in sample preparation and extraction procedures. Variables such as hair length, cosmetic treatment, gender, and pathophysiological conditions influence the final results and should be taken into account.

CONCLUSIONS

EtG quantification in hair is a useful tool for the objective detection of alcohol consumption over extended time periods, but care should be taken when interpreting the results.

Determination of ethyl glucuronide levels in hair for the assessment of alcohol abstinence

This study examined the potential of a highly sensitive LC-MS/MS method for the determination of EtG in head hair (i) to ascertain alcohol abstinence, (ii) to estimate the basal level of EtG (sub-ppb concentrations) in head hair in a population of alcohol abstainers and (iii) to suggest a revision of cut-off values for assessing alcohol abstinence. An UHPLC-MS/MS protocol previously developed was modified and validated again to detect low EtG levels in head hair samples from a population of 44 certain abstainers and teetotalers. Basal level of EtG in hair was determined by a standard addition quantification method. The validated UHPLC-MS/MS method allowed detecting and quantifying 0.5 and 1.0 pg/mg of EtG in hair, respectively. EtG concentrations lower than 1.0 pg/mg were determined for 95% of abstainers; 30% of them had non-detectable (<0.5 pg/mg) EtG values. Two samples evidenced EtG concentrations higher than 1.0 pg/mg that were subsequently explained by unintentional ethanol exposure. The method's feature of high analytical sensitivity makes it particularly suitable for alcohol abstinence ascertainment and, in the same time, allows to tentatively estimate basal EtG concentrations in hair around 0.8±0.4 pg/mg. This finding opens a discussion on the possible origin of basal EtG concentration and potential sources of bias in the evaluation of alcohol abstinence. Cut-off value in the range of 1.0-2.0 pg/mg can be reliably proposed to support alcohol abstinence.

Application of mass spectrometry to hair analysis for forensic toxicological investigations

The increasing role of hair analysis in forensic toxicological investigations principally owes to recent improvements of mass spectrometric instrumentation. Research achievements during the last 6 years in this distinctive application area of analytical toxicology are reviewed. The earlier state of the art of hair analysis was comprehensively covered by a dedicated book (Kintz, 2007a. Analytical and practical aspects of drug testing in hair. Boca Raton: CRC Press and Taylor & Francis, 382 p) that represents key reference of the present overview. Whereas the traditional organization of analytical methods in forensic toxicology divided target substances into quite homogeneous groups of drugs, with similar structures and chemical properties, the current approach often takes advantage of the rapid expansion of multiclass and multiresidue analytical procedures; the latter is made possible by the fast operation and extreme sensitivity of modern mass spectrometers. This change in the strategy of toxicological analysis is reflected in the presentation of the recent literature material, which is mostly based on a fit-for-purpose logic. Thus, general screening of unknown substances is applied in diverse forensic contexts than drugs of abuse testing, and different instrumentation (triple quadrupoles, time-of-flight analyzers, linear and orbital traps) is utilized to optimally cope with the scope. Other key issues of modern toxicology, such as cost reduction and high sample throughput, are discussed with reference to procedural and instrumental alternatives.

Perinatal exposure to alcohol: implications for lung development and disease

In utero alcohol exposure dramatically increases the risk of premature delivery. However, the majority of premature and term newborns exposed to alcohol remain undetected by medical caregivers. There is a desperate need for reliable and accurate biomarkers of alcohol exposure for the term and premature newborn population. The inability to identify the exposed newborn severely limits our understanding of alcohol's pathophysiological effects on developing organs such as the lung. This chapter will review potential advancements in future biomarkers of alcohol exposure for the newborn population. We will discuss alcohol's effects on redox homeostasis and cellular development of the neonatal lung. Finally, we will present the evidence describing in utero alcohol's derangement of innate and adaptive immunity and risk for infectious complications in the lung. Continued investigations into the identification and understanding of the mechanisms of alcohol-induced alterations in the premature lung will advance the care of this vulnerable patient population.

Hydrophilic interaction chromatography in drug analysis

Hydrophilic interaction chromatography (HILIC) is an increasingly popular alternative to conventional HPLC for drug analysis. It offers increased selectivity and sensitivity, and improved efficiency when quantifying drugs and related compounds in complex matrices such as biological and environmental samples, pharmaceutical formulations, food, and animal feed. In this review we summarize HILIC methods recently developed for drug analysis (2006–2011). In addition, a list of important applications is provided, including experimental conditions and a brief summary of results. The references provide a comprehensive overview of current HILIC applications in drug analysis.