Analysis of Cannabinoids and Their Metabolites in Human Urine

Abstract

Biologically monitoring marijuana exposure from active and passive use requires both a wide linear range and sensitive detection. We have developed and validated a multifunctional method using ultrahigh performance liquid chromatography coupled with tandem mass spectrometry (UHPLC–MS/MS) for analysis of urinary Δ9-tetrahydrocannabinol (THC), cannabidiol and cannabinol, and two major metabolites of THC, 11-nor-9-carboxy-THC and 11-hydroxy-THC, in active users and particularly in people exposed to secondhand marijuana smoke (SHMS). The method used positive electrospray ionization (ESI) mode to reach the sensitivity needed to detect trace SHMS exposure with limits of detection (LOD) ranging from 0.002 to 0.008 nanograms per milliliter (ng/mL) and 0.005 to 0.017 ng/mL for “free” (unconjugated forms) and “total” (unconjugated plus conjugated forms) measurements, respectively. These LODs were approximately 10–100 times more sensitive than those reported in the literature. To reduce or avoid time-consuming repetitive sample preparation and analysis, the method simultaneously monitored multiple reaction monitoring transitions in negative ESI mode to quantify high analyte levels typically found in the urine of active marijuana users (linear dynamic range of 12.5–800 ng/mL). The validation results indicated this method was accurate (average inter/intra-day bias, <10%), precise (inter/intra-day imprecision, <10%), and fast (6 min run time). In addition, sample preparation throughput was greatly improved using an automation liquid-handling system, meeting the needs for potential large-scale population studies.

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“…Immunoassays employing a cutoff concentration of 50 ng/mL, [19,20,24] whereas initial tests with a 20 ng/mL cutoff concentration produced multiple positive results. [24] This is important because some private nonregulated drug testing programs utilize lower initial screening cutoffs (e.g., 20 ng/mL), such as non-smokers exposed to secondhand cannabis smoker, [19,20,24] which was contrasted to our study shown negative test result in concentration of THC-COOH lower than 50 ng/mL. Due to cannabis exposure was excreted THCCOOH in urine primarily as a glucuronide conjugate along with small amounts of free metabolite.…”

“…Each sample at same storage condition was extracted and analyzed in triplicate and results were represented as mean ± SD of concentration. [19,20,27] …”

“…There can be determined in hair, OF, and sweat/sebum emulsion and no THC-COOH should be detected. [13,19,20] The prevalence of psychoactive drug use among drivers was early reported in developed countries. Most of them attended to high risk drivers, which were involved in a road crash or being suspected of using the substances when driving.…”

Improved forensic hair evidence for drugs of abuse by mass spectrometry

“…[47] These water cluster ions can yield protonated analyte molecules via proton transfer when the proton affinity of the analyte is higher than that of the ionized water clusters (5). [54,63,64] (8). Again, water cluster ions are formed (4) which can lead to analyte ion formation via proton transfer as described above (5).…”

“…The main metabolite of cocaine is BZE, which is formed by hydrolytic ester cleavage resulting in a carboxylic acid. Where the major metabolite of THC, 11-nor-9-carboxy-THC (THC-COOH), [63] is incorporated in very low concentrations (cut-off value = 0.0002 ng/mg), [20] BZE is incorporated in higher amounts with a SoHT recommended cut-off value of 0.05 ng/mg, compared to 0.5 ng/mg for cocaine. [20] Since cocaine could be detected with sufficient sensitivity, it was anticipated that BZE could be detected as well in drug user hair samples with high cocaine content.…”