Comparison of gas chromatography mass spectrometry methods for the determination of Δ9-tetrahydrocannabinol in plasma

Abstract

A method for the identification of delta9-tetrahydrocannabinol by gas chromatography mass spectrometry has been developed, and this method has been compared with other techniques, such as detection via thin-layer chromatography using tritium labeled delta9-tetrahydrocannibinol and a dual gas chromatographic method. The gas chromatographic mass spectrometric method was found to be equal or superior to other techniques and has the added advantage of being highly specific for the compound analyzed. An alternate approach using chemical ionization is also described; however, this procedure does not show significant advantages over the electron impact method. These methods show a practical lower detection limit of 500 pg ml-1 of plasma in clinical practice.

Determination of Cannabinoids in Water and Human Saliva by Solid-Phase Microextraction and Quadrupole Ion Trap Gas Chromatography/Mass Spectrometry

“…Thus, the analysis time may be shortened by utilizing a shorter GC column or faster ramp allowing up to four analyses per hour. Using a relatively rapid sample preparation procedure of ∼3 min (thus freeing up analysts' time) and traditional positive ion quadrupole ion trap mass spectrometric detection, the SPME method achieves sensitivity equal to or better than many previous techniques of cannabinoid analysis in saliva. − …”

“…Saliva has been successfully used for the detection of cannabinoids, by methods including radioimmunoassay, gas chromatography/mass spectrometry, − gas chromatography with electron capture detection, tandem immunoaffinity chromatography/high-performance liquid chromatography, and high-performance liquid chromatography with amperometric detection …”

“…Gas−liquid chromatography coupled to mass spectrometry stands out as a sensitive and selective method for cannabinoid detection. In an early report, Rosenthal and co-workers reported detection limits of 500 pg/mL for underivatized Δ 9 -tetrahydrocannabinol (Δ 9 -THC) with packed-column GC and selected ion detection . However, the method was based on 3 mL of plasma with a concentration factor of 100×, which translates to a detection level of 100 pg on column.…”

“…After 3-4 h, levels fall below 50 ng/mL and remain detectable at a cutoff limit of 1 ng/mL up to 10 h depending on the strength of the marijuana cigarette smoked. 23,24 Saliva has been successfully used for the detection of cannabinoids, by methods including radioimmunoassay, 25 gas chromatography/mass spectrometry, [26][27][28][29][30] gas chromatography with electron capture detection, 31 tandem immunoaffinity chromatography/ high-performance liquid chromatography, 32 and high-performance liquid chromatography with amperometric detection. 23 Most of these techniques require detailed sample preparation or derivatization prior to analysis to achieve low detection limits.…”

Derivatization in Mass Spectrometry—6. Formation of Mixed Derivatives of Polyfunctional Compounds

“…99 Esterifi cation of the carboxyl group with CH 2 N 2 followed by silylation with BSTFA or acylation with trifluoroacetic anhydride of phenolic and other hydroxyl groups as well as esterifi cation with 2,2,2-trifl uoroethanol and acylation with pentafl uoropropionic anhydride appeared to be the most suitable approaches especially for quantitative determination of the drug metabolite by GC/MS in the NICI mode. 100,101…”