GAS CHROMATOGRAPHY (GC), liquid chromatography (LC), and mass spectrometry (MS) are the techniques at the heart of drug-testing laboratories. These methods also form the basic setup for forensics and criminal investigation labs as well as labs specializing in environmental testing and food safety. "Two basic instruments for testing in the Athens lab are GC with nitrogen-phosphorus detectors for stimulants, and GC with quadrupole MS for smaller molecules, such as stimulants, narcotics, steroids, and diuretics," Georgakopoulos notes. "When there is an initial positive test, GC with time-of-flight MS is typically used for a full-scan confirmatory analysis." Other instruments include GC with combustion isotope ratio magnetic-sector MS. It's used to measure the 13C/12C isotope ratio of CO2 from the combustion of a sample to discriminate between natural and synthetic anabolic steroids, such as testosterone. GC with high-resolution MS is used to detect parts-per-billion or lower levels of synthetic anabolic agents, Georgakopoulos adds. LC with tandem ion-trap mass spectrometry (LC-MS/MS) is used for small polar compounds such as corticosteroids, as well as for direct urine analysis. For blood, gel-permeation LC with UV detection is used for analysis of some compounds.
by STEPHEN RITTER, C&EN WASHINGTON |
August 09, 2004