RESUMEN
Objective:To assay aflatoxin B1 in the oil as a pharmaceutical excipient in soft capsules by LC-MS/MS. Methods:Aflatoxin B1 was extracted from the peanut oil in soft capsules by the solvent composed of methanol and 0. 1% formic acid solution, and then centrifuged and the supernatant was purified by neutral alumina cartridges and tested after the concentration with the mobile phase consisting of methanol and 0. 1% formic acid solution with gradient elution at the flow rate of 0. 3 ml·min-1 . 25μl of the tested solu-tion was injected for the analysis at the column temperature of 30℃. Electrospray ionization ( ESI) source was applied and operated in the position ion mode. Multiple reactions monitoring ( MRM) mode was used to quantify the samples. Results:Aflatoxin B1 was in good linearity within the range of 0. 098-1. 960 μg·L-1(r=0. 999 5). The limit of detection was 0. 05 μg·L-1. The average sampling recovery was 97. 73% (n=6) with RSD of 4. 625%. Conclusion:The method is proved to be sensitive, accurate, specified and re-producible, which is referential for the assay of aflatoxin B1 in oily preparations.