Simultaneous determination of gemcitabine, taxol, cyclophosphamide and ifosfamide in wipe samples by high-performance liquid chromatography/tandem mass spectrometry: protocol of validation and uncertainty of measurement.

Measurable levels of anticancer agents are still detected on work surfaces in health-care settings. However, application of recent guidelines for the protection of workers' safety and health has resulted in lowered contamination levels. To assess occupational exposure to antineoplastic agents, very sensitive and specific procedures for environmental sampling and analysis are therefore needed. In the present study an assay for simultaneous determination of gemcitabine, taxol, cyclophosphamide, and ifosfamide in wipe samples, using two internal standards (trofosfamide and cephalomannine), was developed and validated by high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). Solid-phase extraction (SPE) was used for sample concentration and cleanup. The assay was found to be linear up to 1000 ng/wipe, with limits of quantitation of 25.0 ng/wipe for gemcitabine and taxol, and 12.5 ng/wipe for cyclophosphamide and ifosfamide. In order to investigate the effectiveness of the surface sampling, removal efficiency tests were repeated on different types of surfaces. Recovery rates of between 62 and 81% were obtained at two contamination levels (50.0 and 250 ng/100 cm2). Precision and trueness were determined on three different days. The within-day precision was found to be always less than 12.1% for all the analytes. The overall precision, expressed as relative standard deviation (RSD), was always less than 9.4%. Recoveries varying from 75.0 (gemcitabine) to 95.0% (taxol) were obtained at three levels. In order to obtain a quantitative indication of the quality of the result, the overall uncertainty of measurement (UOM) was evaluated according to the EURACHEM/CITAC guide. The relative combined uncertainty was found to be always less than 9.5%. The relative expanded uncertainty was also calculated, at three contamination levels. Copyright (c) 2007 John Wiley & Sons, Ltd.