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Tandem-in-time mass spectrometry, as implemented on an ion-trap detector (ITD), is the process whereby precursor ions are created, stored in a radio frequency (rf) trapping field, and then sequentially fragmented to form product ions by application of additional rf waveforms. As with any form of tandem mass spectrometry (MS/MS), tandem-in-time MS is highly selective, by virtue of both mass discrimination and specific gas-phase chemistry. Beyond this, however, tandem-in-time MS offers ion throughput efficiency and cost advantages over either quadrupole or sector instruments. This paper will describe the use of capillary gas chromatography combined with tandem-in-time mass spectrometry to quantify a novel therapeutic agent extracted from human plasma. For an example compound, a quantitation limit of 25 pg/mL (S/N approximately 10, 15 fmol on-column) was attained out of plasma. The interday imprecision was < or = 12.2% over a dynamic range extending to 10 ng/mL. Due to favorable ionization conditions for the test analytes, electron ionization resulted in formation of M+ ions, with very little fragmentation, allowing for maximum assay sensitivity. Although method characterization and validation demonstrated adequate instrumental performance, some lack of ruggedness was encountered during routine application.

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A Zymark XP Robot has been adapted to extract a novel anti‐inflammatory drug (CI‐1004) and internal standard (IS) from rat plasma using a batch robotic solid‐phase extraction system. Under computer control, the robot automatically conditions, loads, washes, and elutes up to 144 solid‐phase cartridges in parallel. The system incorporates a miniature pressure transducer to monitor and control manifold vacuum, thereby controlling solvent flow through the cartridges. Liquid chromatographic separation was achieved isocratically on a Zorbax Rx‐C8 analytical column (4.6 mm i.d. × 250 mm). Mobile phase consisted of 65:35 (v/v) acetonitrile and 20 mM ammonium acetate (pH = 4.0). Column effluent was monitored spectrophotometrically at 360 nm. Specificity, chromatographic performance parameters, system repeatability, recovery from matrix, linearity, precision, and accuracy were evaluated. No interfering peaks were observed at the retention time of CI‐1004 throughout the validation process. Peak‐height ratios were proportional to CI‐1004 in rat plasma over the concentration range of 7.5‐5000 ng/mL. The system is capable of extracting 100 plasma samples in approximately 5 hours. © 1996 John Wiley & Sons, Inc.