Comparative analysis of sweat patches for cocaine (and metabolites) by radioimmunoassay and gas chromatography-positive ion chemical ionization-mass spectrometry.

Immunoassays are commonly used to screen samples prior to confirmation by gas chromatography-mass spectrometry (GC-MS). This serves two purposes: it provides a second method for positive samples, and it allows exclusion of negative samples from further confirmatory testing. In addition, immunoassay results can be used in some cases to determine if dilution of the sample will be required during the confirmatory assay.

Quantitative analysis of selegiline and three metabolites (N-desmethylselegiline, methamphetamine, and amphetamine) in human plasma by high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

This report describes a sensitive and specific high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry method for the detection of subnanogram concentrations of selegiline and its three principle metabolites, N-desmethylselegiline, methamphetamine, and amphetamine, in human plasma. The assay has a dynamic range of 0.1-20 ng/mL for selegiline and N-desmethylselegiline (norselegiline) and 0.