Determination of the Malachite Green in Sediment by High Performance Liquid Chromatography with Fluorescence Detection

Abstract

A new method of determination of malachite green (MG) in sediment has been developed by high performance liquid chromatography with fluorescence detection (HPLC-FLD). It is based on use of a deoxidation reaction which converts malachite green (MG) into LMG in the process of extraction. The sediment samples were extracted with a solution of formic acid and acetonitrile. Clean up and isolation was performed on MCX solid phase extraction (SPE) column. Chromatographic separation was achieved by using C18column with an isocratic mobile phase consisting of acetonitrile and ammonium acetate buffer (0.05 M, pH 4.5) (80:20, v/v). High performance liquid chromatography with fluorescence detector (λex=265 nm and λem=360 nm) was used for the determination of LMG. The recovery values of MG in sediment samples fortified with MG were determined by measuring the amount of MG in the samples, after carrying out deoxidation reaction with potassium borohydride, which converts the MG into LMG. Under the optimized conditions, the average recoveries of MG from sediment at three levels (1.0, 10 and 50 μg/kg) were 85.0% (range from 80.8 to 87.6%). Relative standard deviations (RSD) of recoveries at all fortification levels were less than for 9.57% for MG. The method detection limit obtained for MG was 0.5 μg/kg.