The effectiveness of decontamination procedures used in forensic hair analysis

The determination of endogenous steroids in hair and fur: A systematic review of methodologies

BACKGROUND

Endogenous steroid hormone assessment is essential for clinical practice. These hormones are typically measured in blood. More recently, measurement of steroids in hair samples has been gaining in popularity, so we have reviewed the methodologies used for this to-date.

METHODS

Ovid Medline, CINAHL, Psychinfo, and EMBASE were searched to identify manuscripts that analysed cortisol, testosterone, androstenedione, 17-hydroxyprogesterone (17OHP), dehydroepiandrosterone sulphate (DHEAS), and/or 25-hydroxyvitamin D (25(OH)D), in hair or fur. Data related to sampling and measurement procedures were extracted and analysed.

RESULTS

The systematic review included a total of 180 papers, with 82 % published in the past 8 years; 67 % were human and 33 % animal studies. Cortisol was by far the most common analyte. Incomplete reporting on sample harvest, preparation, and measurement procedures was common. Typically, samples were collected from posterior vertex of humans or back/neck of animals, weighing between 11 and 50 mg (with a range of 1.25-1000 mg). Samples were usually stored at room temperature, often using aluminium foil. Isopropanol was the most common cleaning solution. Hair was normally powdered or segmented prior to extraction. Extraction was typically carried out over 18-24 hours using methanol. Validation and precision information was provided in 47 % of studies.

CONCLUSIONS

This systematic review highlights the lack of standardisation in the analysis of endogenous steroids in hair. Reporting was typically incomplete, and assay validations were partial or absent. Together, these limit the value of these exciting new methods and hold back transition to clinical use.

Application of LC-MS/MS for the Identification of Drugs of Abuse in Driver's License Regranting Procedures

Background: Drugged driving is associated with an increased risk of road accidents worldwide. In Italy, driving under the influence (DUI) of alcohol and drugs is a reason for driving disqualification or revocation of the driving license. Drivers charged with driving under the influence of alcohol and drugs must attend a Local Medical Commission (LMC) to undergo mandatory examinations to regain the suspended license. Our study mainly aims to report on the analysis performed on hair samples collected from 7560 drivers who had their licenses suspended for drugged or drunk driving between January 2019 and June 2024. Methods: A rapid, sensitive, and selective method for the determination of ethyl glucuronide in hair by UPLC/MS-MS was developed and fully validated. Results: The most frequently detected substances were cocaine (ecgonine methyl ester, norcocaine, and benzoylecgonine) and cannabinoids (Δ9-tetrahydrocannabinol, cannabidiol, and cannabinol), followed by opiates (codeine, morphine, and 6-MAM), methadone (EDDP), and amphetamines (amphetamine, methamphetamine, MDA, MDMA, and MDEA). To perform a more in-depth analysis, we also compared hair color with the drug classes that tested positive. The results showed a significant prevalence of dark hair that tested positive for one or more substances, followed by gray/white hair and light hair. Conclusions: Our study provides an interesting and alarming insight into drug exposure in the general population with serious public health threats, discussing the main aspects of hair matrix analysis and focusing on its advantages and reliability in the interpretation of results.

Outside-in hair contamination by blood containing opiates and opioids

Hair analysis for drugs has become extensively used for forensic investigation in recent years. To best interpret hair drug content in post-mortem conditions, the extent of external contamination by biological fluids, such as blood, must be taken into account to avoid false positive results. The present study evaluated opiates and opioids incorporation into hair from blood containing different concentrations of morphine (MOR), 6-mono-acetyl morphine (6-AM), codeine (COD), dihydrocodeine (DHC), tramadol (TRA), oxycodone (OXY), methadone (MET), 2-ethylidene-1,5-dimethyl-3,3- diphenyl pyrrolidine (EDDP), buprenorphine (BUP) and norbuprenorphine (NBUP). The hair strands contaminated by brief soaking into blood were stored at room temperature (RT) or at 4°C during 6 hours, 1, 3, 7 or 14 days. After decontamination by extensive washing, we show that all opiates and opioids were incorporated into hair within a few hours at RT and 4°C, without significant changes over time. The concentrations of opiates and opioids in hair reached the cut-off levels established by the Society of Hair Testing (SoHT) for therapeutic (MET, COD), or toxic or lethal (all other molecules) blood concentrations. The metabolite to parent drug concentration ratios were determined for NBUP/BUP, MOR/6-AM and EDDP/MET and could be helpful as indicators of blood external contamination.

A retrospective review of methylamphetamine detected in child deaths reported to the Victorian Coroner, Australia

This study investigated methylamphetamine (MA) exposures in the deaths of children (≤ 12 years old) reported to the Coroner in the state of Victoria, Australia, between 2011 and 2020. Demographics, autopsy findings including the cause of death, self-reported prenatal or caregiver drug use, child protection services information, and toxicological findings were summarized by descriptive statistics. Validated methods of liquid chromatography-tandem mass spectrometry were used in the analysis of drugs. There were 50 child deaths with MA detected in blood, urine, and/or hair with 64% (n = 32) identified in 2018-2020. Most children were 1-365 days old (66%, n = 33) and the cause of death was unascertained in 62% (n = 31) of cases. MA was toxicologically confirmed in hair (94%, n = 47) significantly more than blood (18%, n = 9). Prenatal or caregiver drug use was self-reported in 44% (n = 22) and 42% (n = 21) of cases, respectively. Moreover, only 54% (n = 27) of deceased children were a child protection client at their time of death. These findings suggest the number of deceased children exposed to MA has increased over the past 10 years, which is consistent with the greater supply of crystal MA in the Australian community. Hair analysis provided additional means to identify cases that were unknown to child protection services and may have implications for other children in the same drug exposure environment.

Evaluation of amphetamines diffusion in hair after contact with amphetamines-containing blood

Amphetamine-type stimulants are the third most widely consumed category of illicit drugs worldwide. Faced with the growing problem of amphetamine-type stimulants, numerous qualitative and quantitative techniques have been developed to detect amphetamine (AMP), methamphetamine (MET), MDMA, MDEA or MDA in biological matrices, including hair. Hair analysis is widely used in forensic medicine, but one of its main drawbacks remains external contamination. In this study, we investigated the possibility of hair contamination through external exposure to blood containing AMP, MET MDMA, MDEA or MDA at 2 ng/mL; 20 ng/mL; 200 ng/mL or 2000 ng/mL after 6 h, 1, 3, 7 or 14 days of contact protected from light at room temperature (RT or 20 °C) or at 4 °C. Dried extracts of hair samples were analyzed by UPLC-MS/MS after extensive washings in several baths of water, methanol and acetone before grounding. At the end of our study, contamination of hair was observed from 6 h of contact with all tested amphetamine-type stimulants. The concentrations found in hair ranged from 3 ± 1 to 1464 ± 10 pg/mg, 5 ± 1 to 5070 ± 160 pg/mg, 3 ± 1 to 1269 ± 60 pg/mg, 4 ± 1 to 1860 ± 113 pg/mg and from 8 ± 1 to 1041 ± 44 pg/mg for AMP, MET, MDMA, MDEA and MDA, respectively. Possibly due to its low polar surface area, MET was the most prone to contaminate. As anticipated, hair contamination was mainly dependent on the concentration of all molecules in the contaminating blood, reaching the SOHT cut-off of 200 pg/mg when amphetamine-type stimulants are at toxic or lethal concentrations in the blood. These observations call for caution in interpreting exposure to these substances in such forensic situations.

Surface-enhanced Raman spectroscopy hair analysis after household contamination

Trace evidence found at crime scenes is rarely in an unsullied condition. Surface-enhanced Raman spectroscopy (SERS) is a modern analytical technique that can be used for the detection of artificial hair colourants (S. Higgins and D. Kurouski, Surface-Enhanced Raman Spectroscopy Enables Highly Accurate Identification of Different Brands, Types and Colors of Hair Dyes, Talanta, 2022, 251, 123762). However, contaminants pose a problem to collecting accurate spectra from the dyes. In this study, we sought to analyze how the different physical properties of contaminants can influence the collected spectra. We utilized 11 household substances of varying viscosity and opacity to contaminate hair dyed with permanent black or semi-permanent blue dyes. We discovered that contaminant opacity generally does not affect the spectral quality but that high contaminant viscosity does and that acidic substances could destroy the colourant's spectral identity altogether. Cleaning the contaminated hair with a water rinse allowed the underlying colourant to be identified in 21 out of 22 cases. Overall, this study provided a clearer understanding of the capabilities and limitations of SERS in forensic hair analysis.

The rate and quality of post-mortem hair root changes in relation to melanin content

Hairs is a relatively environmentally resistant biological material that is often found at crime scenes. Human hair is more durable than other biological traces such as blood or urine, and its collection and storage does not require specific preservation procedures. Melanin is the hair pigment, which is the main determinant of hair colour. There are two pigments present in human hair: eumelanin, predominant in dark hair, and pheomelanin, responsible for red colour. Eumelanin is more resistant and has photoprotective properties, while pheomelanin is phototoxic and shows lower resistance to environmental factors. The differences in the properties of eu- and pheomelanin are the basis of the present study, which aimed to examine the rate and quality of taphonomic changes in hair roots in relation to the predominant melanin type, under the influence of selected environmental factors, such as soil pH, degree of exposure to solar radiation, temperature and water from a natural watercourse (river) and chemically pure water. Therefore, changes in blonde, dark, grey, red and dyed hair roots were microscopically documented for six months under the influence of the above factors. The results of the study indicated the strongest degradation potential among acidic soil and a riverine environment, as well as the protective role of eumelanin against environmental taphonomic factors. Degradation occurred most rapidly in the river environment, where microbial activity was additionally observed. Distilled water, exposure to sunlight and low temperature did not lead to decomposition changes. The results of our team's research provide the basis for an extended analysis of the changes occurring in hair under the influence of environmental factors in relation to melanin content.

Performance of Hair Testing for Cocaine Use-Comparison of Five Laboratories Using Blind Reference Specimens

The purpose of this study was to compare results from five commercial hair testing laboratories conducting workplace drug testing with regard to bias, precision, selectivity and decontamination efficiency. Nine blind hair specimens, including cocaine-positive drug user specimens (some contaminated with methamphetamine) and negative specimens contaminated with cocaine, were submitted in up to five replicates to five different laboratories. All laboratories correctly identified cocaine in all specimens from drug users. For an undamaged hair specimen from a cocaine user, within-laboratory Coefficients of Variation (CVs) of 5-22% (median 8%) were reported, showing that it is possible to produce a homogenous proficiency testing sample from drug user hair. Larger CVs were reported for specimens composed of blended hair (up to 29%) and curly/damaged hair (19-67%). Quantitative results appeared to be method-dependent, and the reported cocaine concentrations varied up to 5-fold between the laboratories, making interlaboratory comparisons difficult. All laboratories reported at least one positive result in specimens contaminated with cocaine powder, followed by sweat and shampoo treatments. Benzoylecgonine, norcocaine, cocaethylene and hydroxylated cocaine metabolites were all detected in cocaine powder-contaminated specimens. This indicates that current industry standards for analyzing and reporting positive cocaine results are not completely effective at identifying external contamination. Metabolite ratios between meta- or para-hydroxy-cocaine and cocaine were 6- and 10-fold lower in contaminated specimens compared to those observed in cocaine user specimens, supporting their potential use in distinguishing samples positive due to contamination and drug use.

Determination of 5 synthetic cannabinoids in hair by Segmental analysis using UHPLC-MS/MS and its application to eight polydrug abuse cases

In recent years, an increasing number of new synthetic cannabinoids (SCs) have appeared in the drug trade market. A UPLC-MS/MS method was developed to simultaneously identify five synthetic cannabinoids in 1 cm segment hair samples. The method was fully validated and confirmed to have good selectivity, accuracy, and precision, as well as satisfactory linearity within the calibrated range. The limit of quantification (LOD) was 0.5 pg/mg, and the lower limit of quantitation (LLOQ) was 1 pg/mg, with intraday and interday accuracies (bias) ranging from - 9.6-13.7%. The validated method was successfully used for qualitative and quantitative analysis of five SCs in authentic hair samples of eight SC abusers. SCs were detected in 8 cases at concentrations ranging from 1.5 to 632.9 pg/mg.

Developments in high-resolution mass spectrometric analyses of new psychoactive substances

The proliferation of new psychoactive substances (NPS) has necessitated the development and improvement of current practices for the detection and identification of known NPS and newly emerging derivatives. High-resolution mass spectrometry (HRMS) is quickly becoming the industry standard for these analyses due to its ability to be operated in data-independent acquisition (DIA) modes, allowing for the collection of large amounts of data and enabling retrospective data interrogation as new information becomes available. The increasing popularity of HRMS has also prompted the exploration of new ways to screen for NPS, including broad-spectrum wastewater analysis to identify usage trends in the community and metabolomic-based approaches to examine the effects of drugs of abuse on endogenous compounds. In this paper, the novel applications of HRMS techniques to the analysis of NPS is reviewed. In particular, the development of innovative data analysis and interpretation approaches is discussed, including the application of machine learning and molecular networking to toxicological analyses.

Evaluation of decontamination procedures for drug testing in undamaged vs damaged hair

INTRODUCTION

Although substances incorporated by ingestion are strongly bound to hair, their loss may occur if aggressive decontamination procedures are applied, especially in highly damaged/porous hair.

AIMS

Evaluation of cleaning procedures using hair samples with different porosity obtained from ethanol or drug users (cocaine, heroin, methamphetamine, methadone, fentanyl, tramadol, diazepam, buprenorphine, dihydrocodeine, citalopram and trazodone). The effect of washing time and multiple wash steps with water and methanol were evaluated.

METHODS

Hair samples (n=16) were selected and evaluated according to: a) the drug pattern consumption, b) available amount, and c) hair porosity (c1 'cosmetic treatment', c2: storage time). Six of them were soaked with an aqueous deuterated analogue solution. The samples were cut in 1 cm segments and homogenized. All hair samples were then decontaminated one or six times with 1.5 mL of water or methanol during 1, 5, 15, 30, 60 and/or 90 min (n=1 to 3/sample, depending on the available amount of hair). Hair extracts were then cleaned up via an SPE or LLE extraction, while the washes were evaporated to dryness. All were thereafter reconstituted and analysed with routine UPLC-MS/MS methods.

RESULTS AND DISCUSSION

Although concentrations of parent drugs and/or metabolites presented a negative trend along the washing time with methanol (up to 80%), the compounds were relatively well retained in hair even after a 90 min wash in most samples. Their retention would depend mostly on the hair nature rather than their physicochemical properties (whether incorporated by ingestion and/or from external contamination). Moreover, parent drugs and/or metabolites were detected in the washes in most samples, and the ratio between hair and washes decreased along the washing time. More than 50% of the deuterated analogues soaked into hair were still present after the different washing steps.

CONCLUSION

Generally, the substances analysed were well retained in hair samples after different washing steps with water or methanol. Losses were observed more frequently for long term stored hair samples, after decontamination with methanol for more than 30 min. Therefore, prolonged or repeated cleaning with methanol should be avoided in general procedures.

Silicone Wristbands in Exposure Assessment: Analytical Considerations and Comparison with Other Approaches

Humans are exposed to numerous potentially harmful chemicals throughout their lifetime. Although many studies have addressed this issue, the data on chronic exposure is still lacking. Hence, there is a growing interest in methods and tools allowing to longitudinally track personal exposure to multiple chemicals via different routes. Since the seminal work, silicone wristbands (WBs) have been increasingly used to facilitate human exposure assessment, as using WBs as a wearable sampler offers new insights into measuring chemical risks involved in many ambient and occupational scenarios. However, the literature lacks a detailed overview regarding methodologies being used; a comprehensive comparison with other approaches of personal exposure assessment is needed as well. Therefore, the aim of this review is fourfold. First, we summarize hitherto conducted research that employed silicone WBs as personal passive samplers. Second, all pre-analytical and analytical steps used to obtain exposure data are discussed. Third, we compare main characteristics of WBs with key features of selected matrices used in exposure assessment, namely urine, blood, hand wipes, active air sampling, and settled dust. Finally, we discuss future needs of research employing silicone WBs. Our work shows a variety of possibilities, advantages, and caveats associated with employment of silicone WBs as personal passive samplers. Although further research is necessary, silicone WBs have already been proven valuable as a tool for longitudinal assessment of personal exposure.

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

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.

Alternative matrices in forensic toxicology: a critical review

Purpose

The use of alternative matrices in toxicological analyses has been on the rise in clinical and forensic settings. Specimens alternative to blood and urine are useful in providing additional information regarding drug exposure and analytical benefits. The goal of this paper is to present a critical review on the most recent literature regarding the application of six common alternative matrices, i.e., oral fluid, hair, sweat, meconium, breast milk and vitreous humor in forensic toxicology.

Methods

The recent literature have been searched and reviewed for the characteristics, advantages and limitations of oral fluid, hair, sweat, meconium, breast milk and vitreous humor and its applications in the analysis of traditional drugs of abuse and novel psychoactive substances (NPS).

Results

This paper outlines the properties of six biological matrices that have been used in forensic analyses, as alternatives to whole blood and urine specimens. Each of this matrix has benefits in regards to sampling, extraction, detection window, typical drug levels and other aspects. However, theses matrices have also limitations such as limited incorporation of drugs (according to physical–chemical properties), impossibility to correlate the concentrations for effects, low levels of xenobiotics and ultimately the need for more sensitive analysis. For more traditional drugs of abuse (e.g., cocaine and amphetamines), there are already data available on the detection in alternative matrices. However, data on the determination of emerging drugs such as the NPS in alternative biological matrices are more limited.

Conclusions

Alternative biological fluids are important specimens in forensic toxicology. These matrices have been increasingly reported over the years, and this dynamic will probably continue in the future, especially considering their inherent advantages and the possibility to be used when blood or urine are unavailable. However, one should be aware that these matrices have limitations and particular properties, and the findings obtained from the analysis of these specimens may vary according to the type of matrix. As a potential perspective in forensic toxicology, the topic of alternative matrices will be continuously explored, especially emphasizing NPS.

Determination of steroids in bovine hair: Validation of a microwave-assisted chemical derivatization method using liquid chromatography-tandem mass spectrometry and in vivo studies

Hair analysis has attracted great attention in the regulatory analysis of food-producing animals, particularly due to the wider detection window of veterinary drugs in this matrix and also the possibility of confirming parent drugs with minimum metabolization. This work involved the development and validation of a quantitative liquid chromatography-tandem mass spectrometry method to determine 25 steroids and steroid esters in bovine hair. Sensitivity was improved using a fast and effective microwave-assisted chemical derivatization with methoxyamine hydrochloride. The validation was conducted in accordance with the Decision 657/2002/EC guidelines. An animal experimentation procedure was performed on 12 bovine animals in which two commercial formulations containing boldenone undecylenate and testosterone propionate were administrated via intramuscular injections on the neck. The samples were collected for 78 days in which the detection of the administrated analytes was only observed near the application sites. For some of the monitored days, no analyte was detected on the neck area. Since the migration of the analytes was not observed in areas other than the application site, false-negative results should be carefully considered when monitoring animal hair samples.

Using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) for investigations on single hair samples to solve the contamination versus incorporation issue of hair analysis in the case of cocaine and methadone

Drug testing in hair is a controversial subject of discussion. Claims that decontamination protocols could generate false-positive samples, by washing contamination in hair, have unsettled many toxicologists. At least for zolpidem (known for showing only minor contamination), it could be shown that differentiation of the drug incorporated via the bloodstream from contamination was possible. The current work addresses cocaine and methadone, known for their high concentrations and contamination issues. Longitudinally and cross-sectioned samples of drug-soaked hair, consumer hair and cocaine powder contaminated hair were investigated using time of flight-secondary ion mass spectrometry (ToF-SIMS) and matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). In addition, the resulting wash solutions were investigated using LC-MS/MS. Differentiation of contamination from incorporation was possible for soaked and consumer hair samples. Therefore, contamination could be localized in the superficial compartments of hair and could be removed using strong wash protocols. In the case of powder contaminated hair samples, a small amount of cocaine remained in the inner structures even after the application of the strongest wash protocols. However, taking into consideration the differences in their behavior during decontamination steps compared to both soaked and authentic hair samples, the validity of this contamination protocol (rubbing cocaine powder into hair) must be questioned. Furthermore, when using cut-off values and metabolite ratios (from routine hair analysis), the differentiation of incorporation from contamination was possible also for all our experimental samples in this study. Inclusion of metabolites and application of cut-off values are therefore a must in routine hair analysis.

Get it off, but keep it: Efficient cleaning of hair shafts with parallel DNA extraction of the surface stain

The analysis of hair samples is a common task in forensic investigations. Material transferred to the surface of a hair during a crime challenges the analysis as it has to be removed efficiently. However, the removal of the stain can also lead to a loss of information on stain contributors. DNA analysis of the stain itself might thus be helpful for the forensic investigation. The aim of this study was the examination of different methods to remove common biological surface stains completely from human hair shafts without hampering the parallel DNA extraction of the cleaned hair shaft and the isolated surface stain (blood, saliva, vaginal secretion, semen, and skin flocks). Four different methods of cleaning (water, lysis buffer, swabbing, NaClO) were compared to their cleaning efficiency as well as their success of mtDNA analysis of three hair donors and the original five stains on the hair. In order to test the suitability of this procedure for future analysis methods, a selection of samples were also sequenced with MPS. Additionally, nuclear DNA analysis of the stain DNA was performed using a screening STR assay to test the potential success for detection of a STR profile. The most efficient removal of the stain was achieved using NaClO, however compromising further analysis of the stain DNA. The best results for cleaning and parallel stain analysis were obtained using a swab moistened with 0.5 % SDS for surface cleaning. Especially water failed to remove stains efficiently, leading to a high amount of mixed mtDNA in the DNA extracts. MPS showed an increased sensitivity for detection of minute mixtures.

Hair Analysis: Contamination versus Incorporation from the Circulatory System-Investigations on Single Hair Samples Using Time-of-Flight Secondary Ion Mass Spectrometry and Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

Contamination is a highly controversial issue in hair analysis. Therefore, hair testing protocols typically include wash steps to remove contamination. However, recent studies claim that washing could also lead to permanent incorporation of contaminants into hair, thus questioning the validity of hair testing at all. In the present study, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) with longitudinal sectioning of single hairs and different decontamination protocols was used to reveal differences between the incorporation of a substance into hair from external sources and an incorporation via bloodstream. Single hairs were longitudinally sectioned using a custom-made sample holder. Data were acquired with MALDI-MS by rastering each hair individually. Single hair samples from drug users, blank hairs, and zolpidem- and zolpidem-D6-soaked hairs were investigated. Different published washing protocols were tested, and an in-house washing protocol was developed. For images with higher spatial resolution, time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used. Longitudinal sectioning of hairs dramatically increased sensitivity; even single-dose administrations of zolpidem in single hairs could thus be detected using MALDI-MS. Zolpidem from external sources could be detected in large quantities in superficial hair structures. Zolpidem from consumer hairs, proposed to be strongly bound to inner hair structures, could not be completely removed even by the strongest tested decontamination protocol, whereas zolpidem-soaked hairs could be cleared almost completely with the developed in-house wash protocol. The applied methods allowed a first insight into the connection of decontamination protocols and wash-in phenomena in hair analysis. Further studies with other drugs are necessary to assess the general validity of these findings.