Microscale and Time Shortening Sample Preparation Procedure for Determining Malachite Green and Leucomalachite Green in Cultured eel

To prevent residual chemicals in seafoods, it is important to strengthen the residue monitoring in these foods, and for that purpose, an accurate and efficient quantification method for each target chemical substance is required. In the present chapter, an inexpensive, simple, rapid, and microscale technique of sample preparation followed by high-performance liquid chromatography (HPLC) coupled photodiode array (PDA) detector for simultaneous quantification of malachite green (MG) and its metabolite, leucomalachite green (LMG), in cultured eel is described. The HPLC-PDA was carried out with an isocratic mobile phase on a C4 column. A handheld ultrasonic homogenizer was used to remove analytes from the sample, which were then purified using MonoSpin® C18 centrifugal monolithic SPE spin mini-columns. The recommended strategy has been proven to work by the analyses of spiked eel samples, resulting recoveries > 95% with relative standard deviations < 2% and total analytical time < 15 min/sample (24 samples < 4 hours).