Novel solid-phase extraction protocol for 11-nor-9-carboxy-delta9-tetrahydrocannabinol from urine samples employing a polymeric mixed-mode cation-exchange resin, Strata-X-C, suitable for gas chromatography-mass spectrometry or liquid chromatography-mass spectrometry analysis.
A novel solid-phase extraction (SPE) method was developed for extraction and cleanup of 11-nor-9-carboxy-delta9-tetrahydrocannabinol (THC-COOH), the major metabolite of the active principle of marijuana, delta9-tetrahydrocannabinol, from urine samples. The protocol utilizes a polymeric mixed-mode cationic sorbent, Strata-X-C, which exhibits strong retention for the metabolite facilitating a more rigorous organic wash to eliminate matrix components/endogenous materials. Acetonitrile containing acetic acid was used as the elution solvent and is compatible with both LC-MS and GC-MS modes of analysis. The hydrophobic retention of Strata-X-C was demonstrated to be higher than a neutral polymeric sorbent, Strata-X, of the same backbone but devoid of the cation-exchange moiety (sulfonic acid), by LC studies employing homologous paraben probes. Simultaneously, the polar (non-ionic) interaction capability of Strata-X-C is also greater than that of Strata-X, as assessed through regioisomeric nitrophenol probes. These two features enable the metabolite to be retained strongly on Strata-X-C. Good linearity and precision was obtained for THC-COOH by GC-MS analysis of its trimethylsilyl derivative in the range 1-50 ng. A simplified room temperature instantaneous derivatization procedure was developed that is suitable for high-throughput screening of THC-COOH.
Huq
Shahana
S
Phenomenex Inc., 411 Madrid Avenue, Torrance, CA 90501, USA.
Dixon
Art
A
Kelly
Kory
K
Kallury
Krishna M R
KM
D002411:Cation Exchange Resins; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002852:Chromatography, Ion Exchange / Q000379:methods*; D013759:Dronabinol / Q000031:analogs & derivatives* / Q000652:urine*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D012015:Reference Standards
D002411:Cation Exchange Resins; C016780:11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid; D013759:Dronabinol