Weather-induced changes in cannabinoid content of hair

Authentic hair samples from Cannabis users and a drug free hair sample which was separately spiked with tetrahydrocannabinol (THC), cannabidiol (CBD) or cannabinol (CBN) were exposed outside as well as to natural sunlight at prevailing and elevated humidity in quartz glass tubes during 8 weeks. In addition, authentic and spiked hair samples were exposed to xenon arc radiation in a light exposure cabinet for 24 hours. Stability of THC, CBD and CBN in authentic samples differed from that of the spiked hair. The radiation experiment revealed that CBN could not be measured in hair which had been spiked with THC. Under all conditions chosen the concentrations of THC, CBD and CBN decreased. At high humidity the concentrations declined more rapidly. In both authentic and spiked samples THC was most unstable compared to CBD and CBN. Therefore, in hair analysis determination of CBD and CBN seems promising to detect Cannabis exposure even under unfavorable conditions.     

Characterization of Algerian-Seized Hashish Over Eight Years (2011–2018). Part II: Chemical Categorization

In Algeria, large quantities of hashish are seized every year. This study aimed to investigate the total content of major cannabinoids in the illicit seized hashish in Algeria over an 8-year period (2011–2018) in order to establish the chemical profile of North African hashish. A total of 3265 hashish samples were analyzed using a validated high-performance liquid chromatography–diode array detection (HPLC-DAD) method, allowing the simultaneous quantification of both the acidic and the neutral forms of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN). The results revealed a slight upward trend in the mean THC content, from 7.0% in 2011 to 9.4% in 2018, with an overall mean value of 8.4%. The overall means of CBD and CBN content were 3.5% and 0.8%, respectively. The number of high-potency hashish samples gradually increased to reach 6% in 2018. Two distinct hashish chemotypes were identified: the highly populated chemotype II, corresponding to the traditional medium-potency hashish ([THC + CBN]/CBD ~ 2.16), and chemotype I, containing hashish samples of relatively high THC levels and low levels of CBD (ratio ~ 4.90). Both chemotypes I and II were characterized in the ternary plot, and the proportions (THC:CBD:CBN) were about 85%:13%:2% and 60%:35%:5%, respectively.     

First systematic evaluation of the potency of Cannabis sativa plants grown in Albania

Cannabis products (marijuana, hashish, cannabis oil) are the most frequently abused illegal substances worldwide. Delta-9-tetrahydrocannabinol (THC) is the main psychoactive component of Cannabis sativa plant, whereas cannabidiol (CBD) and cannabinol (CBN) are other major but no psychoactive constituents. Many studies have already been carried out on these compounds and chemical research was encouraged due to the legal implications concerning the misuse of marijuana. The aim of this study was to determine THC, CBD and CBN in a significant number of cannabis samples of Albanian origin, where cannabis is the most frequently used drug of abuse, in order to evaluate and classify them according to their cannabinoid composition. A GC-MS method was used, in order to assay cannabinoid content of hemp samples harvested at different maturation degree levels during the summer months and grown in different areas of Albania. This method can also be used for the determination of plant phenotype, the evaluation of psychoactive potency and the control of material quality. The highest cannabinoid concentrations were found in the flowers of cannabis. The THC concentrations in different locations of Albania ranged from 1.07 to 12.13%. The influence of environmental conditions on cannabinoid content is discussed. The cannabinoid content of cannabis plants were used for their profiling, and it was used for their classification, according to their geographical origin. The determined concentrations justify the fact that Albania is an area where cannabis is extensively cultivated for illegal purposes.     

Characteristics of cannabinoids composition of Cannabis plants grown in Northern Thailand and its forensic application

The Thai government has recognized the possibility for legitimate cultivation of hemp. Further study of certain cannabinoid characteristics is necessary in establishing criteria for regulation of cannabis cultivation in Thailand. For this purpose, factors affecting characteristics of cannabinoids composition of Thai-grown cannabis were investigated. Plants were cultivated from seeds derived from the previous studies under the same conditions. 372 cannabis samples from landraces, three different trial fields and seized marijuana were collected. 100g of each sample was dried, ground and quantitatively analyzed for THC, CBD and CBN contents by GC-FID. The results showed that cannabis grown during March-June which had longer vegetative stages and longer photoperiod exposure, had higher cannabinoids contents than those grown in August. The male plants grown in trial fields had the range of THC contents from 0.722% to 0.848% d.w. and average THC/CBD ratio of 1.9. Cannabis in landraces at traditional harvest time of 75 days had a range of THC contents from 0.874% to 1.480% d.w. and an average THC/CBD ratio of 2.6. The THC contents and THC/CBD ratios of cannabis in second generation crops grown in the same growing season were found to be lower than those grown in the first generation, unless fairly high temperatures and a lesser amount of rainfall were present. The average THC content in seized fresh marijuana was 2.068% d.w. while THC/CBD ratios were between 12.6 and 84.09, which is 10-45 times greater than those of similar studied cannabis samples from the previous study. However, most Thai cannabis in landraces and in trial fields giving a low log(10) value of THC/CBD ratio at below 1 may be classified as intermediate type, whereas seized marijuana giving a higher log(10) value at above 1 could be classified as drug type. Therefore, the expanded information provided by the current study will assist in the development of criteria for regulation of hemp cultivation in Thailand.     

A survey of the potency of Japanese illicit cannabis in fiscal year 2010

In recent years, increased 'cannabis potency', or Δ(9)-tetrahydrocannabinol (THC) content in cannabis products, has been reported in many countries. A survey of Japanese illicit cannabis was conducted from April 2010 to March 2011. In Japan, all cannabis evidence is transferred to the Minister of Health, Labour and Welfare after criminal trials. The evidence was observed at Narcotics Control Department offices in major 11 cities. The total number of cannabis samples observed was 9072, of which 6376 were marijuana. The marijuana seizures were further classified, and it was found that in terms of the number of samples, 65.2% of them were seedless buds, and by weight 73.0% of them were seedless buds. Seedless buds were supposed to be 'sinsemilla', a potent class of marijuana. THC, cannabinol (CBN) and cannabidiol (CBD) in marijuana seizures exceeding 1g were quantified. The number of samples analyzed was 1115. Many of them were shown to contain CBN, an oxidative product from THC. This was a sign of long-term storage of the cannabis and of the degradation of THC. Relatively fresh cannabis, defined by a CBN/THC ratio of less than or equal to 0.1, was chosen for analysis. Fresh seedless buds (335 samples) contained an average of 11.2% and a maximum of 22.6% THC. These values are comparable to those of 'high potency cannabis' as defined in previous studies. Thus, this study shows that highly potent cannabis products are distributed in Japan as in other countries.     

GC-MS/MS法测定人头发中的大麻酚类及其代谢物

目的 建立同时检测头发中△9-四氢大麻酚(THC)、大麻酚(CBN)、大麻二酚(CBD)和△9-四氢大麻酸(THC-COOH)的分析方法.方法头发样品加入氘代内标△9-四氢大麻酸(THC-COOH-d3),经碱水解后,以混合溶剂[V(正己烷)∶V(乙酸乙酯=9∶1]进行提取,吹干,残留物经双(三甲基硅烷基)三氟乙酰胺(BSTFA)衍生化,用GC-MS/MS方法进行分析.结果 头发中THC-COOH、THC、CBN和CBD的最低检出限分别为4、4、10和20 pg· mg-1,各化合物在0.04～5ng· mg-1呈良好的线性关系(r＞0.999),方法精密度、准确度均符合要求.结论本方法选择性强、灵敏度高,适用于头发中CBD、CBN、THC及其代谢物THC-COOH的分析,并成功应用于实际案例中.     

A preliminary investigation on the distribution of cannabinoids in man

An LC/MS/MS procedure to determine THC along with its major metabolites 11-OH-THC, THC-COOH and its glucuronide as well as the cannabinoids CBD and CBN was applied to 5 post mortem cases to study their distribution into some less commonly studied matrices. Analytes were determined in fluids and tissue homogenates following protein precipitation and liquid-liquid extraction. Gall bladder fluid exhibited maximum concentrations of all analytes except THC, which was detectable in high concentrations in muscle tissue along with CBD. THC was also present in lung specimens, whereas its concentration in liver samples was low or not detectable at all. Liver und kidney specimens contained appreciable amounts of THC-COOglu. Findings from bile support extensive enterohepatic recirculation of the glucuronide. Muscle tissue seems an interesting specimen to detect multiple cannabis use, and brain may serve as an alternative specimen for blood; nevertheless, the present findings should be substantiated by further investigations.     

Deposition of cannabinoids in hair after long-term use of cannabis

Hair analysis has shown great potential in the detection and control of drug use. Whether an assay is of quantitative value roughly corresponding to the amount of drug consumed, is still a matter of debate. The present investigation was aimed at a possible relationship between the cannabinoid concentration in hair and the cumulative dose in regular users of cannabis. Hair samples from the vertex region of the scalp were obtained from 12 male regular users of cannabis, and 10 male subjects with no experience of cannabis served as controls. None of the subjects had his hair permed, bleached or colored. Cannabis users provided information on drug use such as the current cannabis dose per day, the cumulative cannabis dose of the last 3 months, as well as the frequency of cannabis use during the last year. The concentration of delta-9-tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidiol (CBD) in hair was determined using gas chromatography-mass spectrometry. Cannabinoids were present in any hair sample of cannabis users, but were not detectable in control specimens. An increase in the amount of cannabinoids in hair with increasing dose was evident. The concentration of major cannabinoids (sum of THC, CBD and CBN) was significantly correlated to either the reported cumulative cannabis dose during the last 3 months or to the cannabis use during the last 3 months estimated from the daily dose and the frequency per year (r=0.68 or 0.71, p=0.023 or 0.014). A significant relationship between THC and the amount of cannabis used could not be established. As a conclusion, the sum of major cannabinoids in hair of regular users may provide a better measure of drug use than THC.     

Potency of delta 9-THC and other cannabinoids in cannabis in England in 2005: implications for psychoactivity and pharmacology

Gas chromatography was used to study the cannabinoid content ("potency") of illicit cannabis seized by police in England in 2004/5. Of the four hundred and fifty two samples, indoor-grown unpollinated female cannabis ("sinsemilla") was the most frequent form, followed by resin (hashish) and imported outdoor-grown herbal cannabis (marijuana). The content of the psychoactive cannabinoid delta 9-tetrahydrocannabinol (THC) varied widely. The median THC content of herbal cannabis and resin was 2.1% and 3.5%, respectively. The median 13.9% THC content of sinsemilla was significantly higher than that recorded in the UK in 1996/8. In sinsemilla and imported herbal cannabis, the content of the antipsychotic cannabinoid cannabidiol (CBD) was extremely low. In resin, however, the average CBD content exceeded that of THC, and the relative proportions of the two cannabinoids varied widely between samples. The increases in average THC content and relative popularity of sinsemilla cannabis, combined with the absence of the anti-psychotic cannabinoid CBD, suggest that the current trends in cannabis use pose an increasing risk to those users susceptible to the harmful psychological effects associated with high doses of THC.     

Cannabinoids determination in oral fluid by SPME–GC/MS and UHPLC–MS/MS and its application on suspected drivers

The confirmation of Δ9-tetrahydrocannabinol (THC) in oral fluid (OF) is an important issue for assessing Driving Under the Influence of Drugs (DUID). The aim of this research was to develop a highly sensitive method with minimal sample pre-treatment suitable for the analysis of small OF volumes (100 μL) for the confirmation of cannabinoids in DUID cases. Two methods were compared for the confirmation of THC in residual OF samples, obtained from a preliminary on-site screening with commercial devices. An ultra high performance LC–MS (UHPLC–MS/MS) method and an SPME–GC/MS method were hence developed. 100 μL of the residual mixture OF/preservative buffer or neat OF was simply added to 10 μL of THC-D3 (1 μg/mL) and submitted to the two different analyses: A — direct injection of 10 μL in UHPLC–MS/MS in positive electrospray ionisation (ESI) mode and B — sampling for 30 min with SPME (100 μm polydimethylsiloxane or PDMS fibre) and direct injection by desorption of the fibre in the GC injection port.The lowest limit of detection (LLOD) of THC was 2 ng/mL in UHPLC–MS/MS and 0.5 ng/mL in SPME–GC/MS. In addition, cannabidiol (CBD) and cannabinol (CBN) could be detected in GC/MS equipment at 2 ng/mL, whilst in UHPLC–MS/MS the LLOD was 20 ng/mL.Both methods were applied to 70 samples coming from roadside tests. By SPME–GC/MS analysis, THC was confirmed in 42 samples, whilst CBD was detected in 21 of them, along with CBN in 14 samples. THC concentrations ranged from traces below the lowest limit of quantification or LLOQ (2 ng/mL) up to 690 ng/mL.     

A PCR marker Linked to a THCA synthase Polymorphism is a Reliable Tool to Discriminate Potentially THC‐Rich Plants of Cannabis sativa L.

Neither absolute THC content nor morphology allows the unequivocal discrimination of fiber cultivars and drug strains of Cannabis sativa L. unequivocally. However, the CBD/THC ratio remains constant throughout the plant's life cycle, is independent of environmental factors, and considered to be controlled by a single locus (B) with two codominant alleles (B_T and B_D). The homozygous B_T/B_T genotype underlies the THC‐predominant phenotype, B_D/B_D is CBD predominant, and an intermediate phenotype is induced by the heterozygous state (B_T/B_D). Using PCR‐based markers in two segregating populations, we proved that the THCA synthase gene represents the postulated B locus and that specific sequence polymorphisms are absolutely linked either to the THC‐predominant or the THC‐intermediate chemotype. The absolute linkage provides an excellent reliability of the marker signal in forensic casework. For validation, the species‐specific marker system was applied to a large number of casework samples and fiber hemp cultivars.     

Quantitative Determination of Cannabinoids in Cannabis and Cannabis Products Using Ultra‐High‐Performance Supercritical Fluid Chromatography and Diode Array/Mass Spectrometric Detection

Ultra‐high‐performance supercritical fluid chromatography (UHPSFC ) is an efficient analytical technique and has not been fully employed for the analysis of cannabis. Here, a novel method was developed for the analysis of 30 cannabis plant extracts and preparations using UHPSFC /PDA ‐MS . Nine of the most abundant cannabinoids, viz . CBD , ?⁸‐THC , THCV , ?⁹‐THC , CBN , CBG , THCA ‐A, CBDA , and CBGA , were quantitatively determined (RSD s < 6.9%). Unlike GC methods, no derivatization or decarboxylation was required prior to UHPSFC analysis. The UHPSFC chromatographic separation of cannabinoids displayed an inverse elution order compared to UHPLC . Combining with PDA ‐MS , this orthogonality is valuable for discrimination of cannabinoids in complex matrices. The developed method was validated, and the quantification results were compared with a standard UHPLC method. The RSD s of these two methods were within ±13.0%. Finally, chemometric analysis including principal component analysis (PCA ) and partial least squares‐discriminant analysis (PLS ‐DA ) were used to differentiate between cannabis samples.     

Hair analysis for delta(9)-THC,delta(9)-THC-COOH,CBN and CBD,by GC/MS-EI. Comparison with GC/MS-NCI for delta(9)-THC-COOH

A sensitive analytical method was developed for quantitative analysis of delta(9)-tetrahydrocannabinol (delta(9)-THC), 11-nor-delta(9)-tetrahydrocannabinol-carboxylic acid (delta(9)-THC-COOH), cannabinol (CBN) and cannabidiol (CBD) in human hair. The identification of delta(9)-THC-COOH in hair would document Cannabis use more effectively than the detection of parent drug (delta(9)-THC) which might have come from environmental exposure. Ketamine was added to hair samples as internal standard for CBN and CBD. Ketoprofen was added to hair samples as internal standard for the other compounds. Samples were hydrolyzed with beta-glucuronidase/arylsulfatase for 2h at 40 degrees C. After cooling, samples were extracted with a liquid-liquid extraction procedure (with chloroform/isopropyl alcohol, after alkalinization, and n-hexane/ethyl acetate, after acidification), which was developed in our laboratory. The extracts were analysed before and after derivatization with pentafluoropropionic anhydride (PFPA) and pentafluoropropanol (PFPOH) using a Hewlett Packard gas chromatographer/mass spectrometer detector, in electron impact mode (GC/MS-EI). Derivatized delta(9)-THC-COOH was also analysed using a Hewlett Packard gas chromatographer/mass spectrometer detector, in negative ion chemical ionization mode (GC/MS-NCI) using methane as the reagent gas. Responses were linear ranging from 0.10 to 5.00 ng/mg hair for delta(9)-THC and CBN, 0.10-10.00 ng/mg hair for CBD, 0.01-5.00 ng/mg for delta(9)-THC-COOH (r(2)>0.99). The intra-assay precisions ranged from <0.01 to 12.40%. Extraction recoveries ranged from 80.9 to 104.0% for delta(9)-THC, 85.9-100.0% for delta(9)-THC-COOH, 76.7-95.8% for CBN and 71.0-94.0% for CBD. The analytical method was applied to 87 human hair samples, obtained from individuals who testified in court of having committed drug related crimes. Quantification of delta(9)-THC-COOH using GC/MS-NCI was found to be more convenient than GC/MS-EI. The latter may give rise to false negatives due to the detection limit.     

Cannabis plants illicitly grown in Jutland (Denmark)

Four hundred forty-nine fresh cannabis plants and 26 fruiting tops harvested in Jutland (Denmark) from July to September 1988 were characterized according to weight, height, marihuana yield, and cannabinoid content. The median weights were 308 g and 584 g for plants grown outdoors (n = 418) and in greenhouses (n = 31), respectively. The average marihuana yield was 8.7% for the plants grown outdoors and slightly lower for the greenhouse plants. Great variations, however, were seen both between and within the individual harvests. The mean concentration of total THC (tetrahydrocannabinol) was 0.87% for the plants grown outdoors. An increase according to the month of harvest was observed. For plants grown in greenhouses the mean value of total THC was 1.35%, while the mean concentration of fruiting tops was 2.13%. All plants contained cannabidiol (CBD), but only negligible concentrations of other cannabinoids. In approximately 80% of the plants the THC content was higher than the CBD content (drug type), while the rest either contained equal concentrations (intermediate type) or most CBD (fiber type).     

Validation of the 4‐aminophenol color test for the differentiation of marijuana‐type and hemp‐type cannabis

The analysis of cannabis plant material submitted to seized‐drug laboratories was significantly affected by the signing of the Agricultural Improvement Act of 2018, which defined hemp and removed it from the definition of marijuana in the Controlled Substances Act. As a result, field law enforcement personnel and forensic laboratories now are in need of implementing new protocols that can distinguish between marijuana‐type and hemp‐type cannabis. Colorimetric tests provide a cost‐effective and efficient manner to presumptively identify materials prior to submission to a laboratory for analysis. This work presents the validation of the 4‐aminophenol (4‐AP) color test and demonstrates its utility for discriminating between marijuana‐type and hemp‐type cannabis (i.e., typification). Validation studies included the testing of numerous cannabinoid reference materials, household herbs, previously characterized cannabis plant samples, and real‐case samples. The 4‐AP test reliably produces a pink result when the level of Δ⁹‐tetrahydrocannabinol (THC) is approximately three times lower than the level of cannabidiol (CBD). A blue result is generated when the level of THC is approximately three times higher than that of CBD. Inconclusive results are observed when the levels of THC and CBD are within a factor of three from each other, demonstrating the limitations of the test under those scenarios.     

Determination of cannabinoids in biological samples using a new solid phase micro-extraction membrane and liquid chromatography-mass spectrometry

A simple, rapid and relatively solventless method for extraction of objective compounds would be useful for forensic, judicial and clinical purposes. Solid phase micro-extraction membrane (SPMEM) is one such extraction technique that integrates sampling, extraction and concentration into a single step, and combines the advantages of both the solid phase micro-extraction (SPME) and membrane separation. In this study, a new kind of membrane was prepared using polyamide and Tenax compounds, and applied to solid phase micro-extraction. Characteristics of the membrane such as adsorption capacity were tested. Extraction conditions such as adsorption time, desorption solvents, desorption time and assisted desorption treatment methods were studied and optimized. Tetrahydrocannabinol (THC) and cannabidiol (CBD) in blood and brain of the injected male mice, and in spiked human urine were extracted using this solid phase micro-extraction membrane method. The extracted THC and CBD were further determined with LC-MS using APCI. Ions analyzed in single ion monitoring mode were 315 for THC and CBD, and 318 for the deuterated THC internal standard.     

Chemical identification and optimization of the 4-aminophenol colorimetric test for the differentiation between hemp-type and marijuana-type cannabis plant samples

The 4- Aminophenol (4-AP) colorimetric test is a fast, easy-to-use, and cost-effective presumptive assay of cannabis plant material producing different chromophores with THC-rich cannabis (blue color) and with CBD-rich cannabis (pink color). The main drawback of the 4-AP test is a brief observation window where the color rapidly changes to black, limiting the utility of the test. We now report for the first time, the identification of the product chromophores between 4-AP and CBD/THC as well as propose an explanation and a solution for the color degradation of the chromophores. The identification of the chromophores is provided by spectroscopic (UV–Vis), chromatography, and mass spectrometry (TLC and LC-QToF-MS). Oxidation of excess 4-AP (Reagent A) in the presence of NaOH (Reagent B) produces the black color observed for the previously reported 4-AP tests and reported in the literature. The adjustment of reactants concentrations and volumes of 4-AP:THC/CBD to a 1:1 ratio significantly reduces the black oxidation by-product and increases the observation window up to 2 h instead of the previously reported 5–10 min. For the first time, mass spectrometry and chromatography confirmed that the reaction of THC and CBD with 4-AP produced chromophores with m/z (M + H) = 420, consistent with proposed indophenol structures. The TLC method developed confirmed the separation between CBD and THC chromophores. The specificity of the test is also reported, showing false positive results for the presence of THC (blue color) for samples of thyme and oregano. LDA and SIMCA models showed that the optimized 4-AP procedure performs better than the previously reported 4-AP color test.     

Comparison of bulk and compound-specific δ13C isotope ratio analyses for the discrimination between cannabis samples

Five marijuana samples were compared using bulk isotope analysis compound-specific isotope ratio analysis of the extracted cannabinoids. Owing to the age of our cannabis samples, four of the five samples were compared using the isotope ratios of cannabinol (CBN), a stable degradation product of Δ(9)-tetrahydrocannabinol (THC). Bulk δ(13)C isotope analysis discriminated between all five samples at the 95% confidence level. Compound-specific δ(13)C isotope analysis could not distinguish between one pair of the five samples at the 95% confidence level. All the measured cannabinoids showed significant depletion in (13)C relative to bulk isotope values; the isotope ratios for THC, CBN, and cannabidiol were on average 1.6‰, 1.7‰, and 2.2‰ more negative than the bulk values, respectively. A more detailed investigation needs to be conducted to assess the degree fractionation between the different cannabinoids, especially after aging.     

大麻的体内代谢物THC—COOH的分析

本文介绍了定性定量分析大麻的主要代谢物ＴＨＣ－ＣＯＯＨ的两种方法。所有试管硅烷化，尿样碱性水解。ＴＬＣ法快速、简便，适用于多份检材的同时定性分析，最低检测限为５０ｎｇ．采用衍生化、ＳＩＭ的ＧＣ／ＭＳ方法灵敏，选择性、专一性强．五氟丙酸酐衍生化方法线性范围为２０－２５０ｎｇ／ｍｌ，最低检测限１０ｎｇ／ｍｌ，变异系数为８．４％，提取回收率为５８．９％；甲基化方法线性范围１０～１００ｎｇ／ｍｌ，最低检测限５ｎｇ／ｍｌ，变异系数为５．６％，提取回收率为５３．２％．     

Use of headspace solid-phase microextraction (HS-SPME) in hair analysis for organic compounds

Headspace solid phase microextraction (HS-SPME) has advantages of high purity of the extract, avoidance of organic solvents and simple technical manipulation and can be used in combination with gas chromatography-mass spectrometry (GC-MS) in the hair analysis of a number of drugs. HS-SPME coupled with the hydrolysis of the hair matrix by 4% sodium hydroxide in the presence of excess sodium sulphate and of a suitable internal standard proved to be a convenient one-step method for the measurement of many lipophilic basic drugs such as nicotine, amphetamine derivatives, local anaesthetics, phencyclidine, ketamine, methadone, diphenhydramine, tramadol, tricyclic antidepressants and phenothiazines. Detection limits were between 0.05 and 1.0 ng/mg. From spiked 10-mg hair samples absolute recoveries between 0.04 and 5.7% were found. These recoveries decreased considerably if larger sample amounts were used, perhaps due to increased drug solubility in the aqueous phase or to elevated viscosity in the presence of dissolved hair proteins. Because of the phenolic hydroxyl group a change of pH after alkaline hair digestion (by adding excess orthophosphoric acid) was necessary for the detection of delta 9-tetrahydrocannabinol (delta 9-THC), cannabinol (CBN) and cannabidiol (CBD) by HS-SPME. Nevertheless, the detection limits were such that only CBN could be detected in hair of a consumer. Clomethiazole, a compound hydrolysed in alkali, was measured by HS-SPME after extraction with aqueous buffer. The detection limit was 0.5 ng/mg. Cocaine could not be detected by HS-SPME. The application of HS-SPME to hair samples from several forensic and clinical cases is described.