Quantitative determination of five cannabinoids in blood and urine by gas chromatography tandem mass spectrometry applying automated on‐line solid phase extraction

Abstract

Cannabis is the most frequently consumed illegal substance worldwide. More recently, an increasing number of legal cannabis products low in psychoactive Δ 9 -tetrahydrocannabinol (THC) but high in non-intoxicating cannabidiol (CBD) are being more widely consumed. While the detection and quantification of THC and its metabolites in biological matrices is an important forensic-toxicological task, additional detection of CBD is also important, for example, when examining the plausibility of consumer's statements. This report describes the method validation for the quantitative determination of THC and its two major metabolites, 11-hydroxy-THC (OH-THC) and 11-nor-9-carboxy-THC (THC-COOH), as well as CBD and cannabinol (CBN) in whole blood and urine. The method employs automated on-line solid phase extraction coupled to gas chromatography tandem mass spectrometry (GC-MS/MS). The method was fully validated according to guidelines of the Swiss Society of Legal Medicine (SGRM) and the Society of Toxicological and Forensic Chemistry (GTFCh). The method fulfilled the validation criteria regarding analytical limits, accuracy and precision, extraction efficacy, and sample stability. The limits of detection (LODs) in whole blood and urine were 0.15 ng/mL for THC, OH-THC and CBD, 0.1 ng/mL for CBN, and 1.0 ng/mL for THC-COOH. The limits of quantification (LOQ) in whole blood and urine were 0.3 ng/mL for THC, OH-THC and CBD, 0.2 ng/mL for CBN, and 3.0 ng/mL for THC-COOH. The fully validated and automated method allows sensitive and robust measurement of cannabinoids in whole blood and urine. Detection of CBD provides additional information regarding consumed products. K E Y W O R D S cannabinoids, driving under the influence of drugs, GC-MS/MS, on-line solid phase extraction Correction added on April 22, 2022, after first online publication: CSAL funding statement has been added.

The Determination of Cannabinoids in Urine Samples Using Microextraction by Packed Sorbent and Gas Chromatography-Mass Spectrometry

“…The same happens when using systems with greater sensitivity, such as LC–MS/MS [ 38 , 39 , 40 , 42 , 45 , 46 , 47 , 48 , 49 ]. Nonetheless, some authors report lower LLOQs than those obtained with our MEPS–GC–MS, mostly using techniques with greater sensitivity, including GC–MS/MS [ 50 , 51 , 52 , 53 ] and LC–MS/MS [ 38 , 39 , 42 , 46 , 54 , 55 , 56 , 57 , 58 , 59 ]; several of these approaches also used larger sample volumes. Table 2 summarizes the information.…”

“…Frozen urine samples were thawed at room temperature and centrifuged for 15 min at 4500 rpm before analysis. Authentic urine samples were hydrolyzed before extraction according to the literature [ 31 , 51 , 55 , 56 , 57 , 58 ]. Hydrolysis was performed by mixing urine (250 µL) with 10 µL of 10 M NaOH and incubating for 15 min at 60 °C.…”

A Validated Liquid–Liquid Extraction Method for the Quantitative Analysis of Ethanol in the Different Types of Home-Brewed Alcoholic Beverages of Botswana Using Gas Chromatography Flame Ionization Detector

“…The percentage (%) recovery results (Table 2 ) obtained at each concentration level ranged between 97.1 and 99.1%, indicating insignificant interference from the excipients. Several authors have also reported acceptable accuracy ranging from 90 to 110% [ 42 , 55 ]. According to Kumar et al, acceptance criteria of accuracy range should at least be 80–120% of expected content [ 56 ].…”

“…Ethanol is the most common analyte identified in forensic toxicology laboratories [38][39][40][41]. There are numerous analytical methods for determination of alcohol content from different alcoholic beverages already available worldwide [42,43]. However, in Botswana known alcohol concentrations are only limited to commercially sold drinks and excludes the homemade types.…”

Simple Method for the Determination of THC and THC-COOH in Human Postmortem Blood Samples by Gas Chromatography—Mass Spectrometry

“…For this reason, the determination of 11-nor-9-carboxy-THC (∆9-THC-COOH) in forensic toxicology laboratories is of special interest, to distinguish between the use of legal cannabis (mainly with CBD) and that of cannabis as a drug of abuse (mainly ∆9-THC, from which the inactive metabolite ∆9-THC-COOH is derived). This is especially important in countries where the use of high-CBD, low-THC cannabis products is legal to verify drug withdrawal [10].…”