METHOD OPTIMIZATION FOR THE ANALYSIS OF AMPHETAMINES IN URINE BY SOLID-PHASE MICROEXTRACTION

Solid-phase microextraction is under investigation in many laboratorie s for its usefulness in the analysis of an ever widening variety of co mpounds. As new classes of compounds are investigated and new challeng es arise, the methods are adapted to accommodate them. Polar semivolat iles are increasingly under study as analytical targets, and difficult ies with small partition coefficients and long equilibration times hav e been identified. Amphetamine and methamphetamine were selected as se mivolatiles exhibiting these limitations, and methods to optimize thei r analyses were investigated. Amphetamines are frequently monitored in very complex matrixes. Headspace methods minimize interactions betwee n the sample and the fiber and have proven useful for these analyses. Several areas of experimental design were considered in the process of method optimization. These included matrix modification by heating, s tirring, methanol content, addition of salt, and pH buffering. It was found that these amphetamines could be reliably analyzed using modifie d sample conditions, with excellent sensitivity, limits of detection, and method linearity. Clinical urine samples were successfully analyze d and gave clean chromatograms with no interfering peaks. Finally, the method developed was found to be useful for the analysis of narcotic analgesics. In the future, it is hoped that the method can be used to develop a general screen for a wide range of drugs of abuse.