title: Quantitative selected ion monitoring (QSIM) of drugs and/or drug metabolites in biological matrices.
abstract: From a modest beginning, QSIM has established itself with over three hundred applications in the 1970s as not only a reference technique for other methods but also as a useful method in its own right for the quantitation of drugs in biological matrices. Relative to its potential sensitivity, the actual sensitivity of QSIM drug assays is disappointing, although a number of QSIM drug assays report LOQs of 250 pg ml-1 or less. The mean reported precision of QSIM drug assays (approximately 6%) is similar to that of traditional GC and LC assays, but is an order of magnitude less than either what is theoretically possible or what has been demonstrated in a few selected QSIM assays.
mesh_terms: D001682:Biological Availability; D005069:Evaluation Studies as Topic; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D004364:Pharmaceutical Preparations / Q000097:blood* / Q000378:metabolism / Q000652:urine; D012016:Reference Values
chemical_list: D004364:Pharmaceutical Preparations