Inoue, Shigeaki, et al. Journal of pharmaceutical and biomedical analysis, 2007, 44(1), 258-264.
A simple and rapid liquid chromatography-atmospheric pressure ionization mass spectrometry (LC-APCI-MS) method was established for the determination of 10 organophosphorus pesticides (acephate, fenitrothion, dichlorvos, fenthion, EPN, diazinon, fenthion, malathion, fenitrothion and fenthion) in the serum of acutely poisoned patients. Diazinon D10 was used as the internal standard (IS) for acephate, fenitrothion, dichlorvos, fenthion, EPN, diazinon, fenthion and malathion
Preparation of Calibration Standards and Quality Control Samples
· Primary stock solutions of each organophosphorus compound (1 mg/ml) were prepared in methanol. Working standard solutions of the compounds were prepared by combining the aliquots of each primary solution and diluting with methanol. The internal standard (IS) solutions for fenitrothion-d6 (3 g/ml) and diazinon-d10 (50 g/ml) were made by diluting aliquots of their respective stock solutions with methanol. All organophosphate solutions were stored at -20 ◦C in the dark when not in use.
· Calibration standards for organophosphates in human serum (0.1, 0.25, 0.5, 1, 2, 5, and 8 µg/ml) were prepared by spiking working standard solutions into 200 µl of drug-free human serum. Quality control (QC) samples at concentrations of 0.625, 2.5, and 7.5 µg/ml were also prepared in bulk by adding the appropriate working standard solutions to 200 µl of drug-free human serum.
