Determination of methotrexate in human urine at trace levels by solid phase extraction and high‐performance liquid chromatography/tandem mass spectrometry

Laboratory of Environmental Hygiene and Industrial Toxicology, Salvatore Maugeri Foundation, via Alzaia 29, Pavia, Italy.
Rapid Communications in Mass Spectrometry (Impact Factor: 2.64). 01/2000; 14(3):173-9. DOI: 10.1002/(SICI)1097-0231(20000215)14:3<173::AID-RCM862>3.0.CO;2-K
Source: PubMed

ABSTRACT For biological monitoring of hospital personnel occupationally exposed to antineoplastic agents, highly sensitive and specific methods are required. In order to detect trace MTX urinary concentrations, a precise and accurate high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) procedure, incorporating solid phase extraction, has been developed. Urine samples were purified by solid phase extraction (SPE) on octadecyl bonded, endcapped silica SPE columns. After eluting with methanol, the solvent was evaporated obtaining a 25-fold concentration of the analyte. This procedure was validated by using 7-OHMTX as internal standard. Calibration curves had correlation coefficients always higher than 0.999, and the limit of detection was assessed at 0.2 microg L(-1). High specificity of the HPLC-MS/MS technique assures that no interfering substances are detected rather than the analyte of interest.