Quantification of cannabinoids in human hair using a modified derivatization procedure and liquid chromatography-tandem mass spectrometry

Analysis of Cannabinoids in Biological Specimens: An Update

Cannabinoids are still the most consumed drugs of abuse worldwide. Despite being considered less harmful to human health, particularly if compared with opiates or cocaine, cannabis consumption has important medico-legal and public health consequences. For this reason, the development and optimization of sensitive analytical methods that allow the determination of these compounds in different biological specimens is important, involving relevant efforts from laboratories. This paper will discuss cannabis consumption; toxicokinetics, the most detected compounds in biological samples; and characteristics of the latter. In addition, a comprehensive review of extraction methods and analytical tools available for cannabinoid detection in selected biological specimens will be reviewed. Important issues such as pitfalls and cut-off values will be considered.

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

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

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.