UHPLC-MS/MS Determination of Residual Amounts of Malachite Green and Leuco-malachite Green in Aquatic Products

UHPLC-MS/MS was applied to the determination of residual amounts of malachite green and leuco-malachite green in aquatic products. The sample was extracted with acetonitrile and purified on neutral alumina solid phase column. The residue was taken up with 2 mL of mixture of acetonitrile and NH4OAc solution and separated by C18 chromatographic column and determined by MS/MS. The malachite green D5 and leuco-malachite green D6 were used as internal standards. Linearity ranges of malachite green and leuco-malachite green were found in the same range of 0.25-20.0 μg·L-1, with lower limits of determination of 0.50 μg·kg-1. Using blank samples of grass carp and large yellow croaker as matrixes, test for recovery was made by standard addition method, giving recovery of malachite green in the range of 80.2 %-105% and leuco-malachite green in the range of 85.1%-104%, with RSD′s (n=6) less than 8%.