SOFT - TIAFT 1998 | Poster Session 4 | Friday October 9, 1998 |
APPLICATION OF CHROMATOPROBE AND ION TRAP CHEMICAL IONIZATION/MASS SPECTROMETRY (CI/MS) FOR DETECTION OF GAMMA-HYDROXYBUTRYRIC ACID (GHB) Cheryl A. Ehorn and Joe Faulkner*
Varian Chromatography Systems, Walnut Creek, CA, USA |
Procedures for rapid, sensitive and specific identification of gamma-Hydroxybutryric acid (GHB) are presented showing confirming results in samples collected from a clandestine laboratory. The ChromatoProbe is a sample introduction device fitted to a temperature programmable injector of an Ion Trap GC/MS. Both solid and liquid samples suspected of containing GHB are quickly analyzed without extraction or derivatization giving positive confirmation by CI/MS. The method uses less then 1 uL of liquid or a few grains of solid placed into a microvial. Sample delivery is controlled by the injector temperature and the split flow ratio. Starting from a temperature of 70 degrees C, the injector is programmed at a rate of 200 degrees C/min to adequately vaporize the sample for transfer to the MS. The GHB is separated from a matrix by either using an analytical column and programming the GC oven, or using a short (1 - 2 meter) column and applying MS/MS. Flow rates through the injector split vent are maintained at 25mL/min. This minimizes the introduction of air into the injector when changing samples. Positive-ion acetonitrile (CH3CN) chemical ionization with full scan MS gives confirming protonated molecules (MH+) and an adduct ion thus providing a high degree of specificity for identification. The ChromatoProbe with Ion Trap GC/MS can also be utilized for the analysis of GHB in urine or blood of persons suspected of being under the influence, adulterated beverages, or clandestine samples. |
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