Determination of Malachite Green in Aquaculture Water by Adsorptive Stripping Voltammetry

An adsorptive stripping voltammetric method for the determination of malachite green in aquaculture water has been developed. Initial studies were made using the cyclic voltammetry of malachite green at a glassy carbon electrode in 0.1M phosphate buffer from pH 2 to 10. The redox behavior observed for malachite green was verified by the characterization of malachite green and its reduction product, leucomalachite green. Furthermore, leucomalachite green was found not to interfere with the determination of malachite green at pH 7.4, the optimum pH for malachite green determination. As a result, further studies were performed using adsorptive stripping voltammetry for the determination of malachite green in aquaculture water. The voltammetric waveform, accumulation potential, and accumulation time were optimized. The calibration plot was linear from 0.2 mu M to 1.2 mu M for malachite green using differential pulse voltammetry with a sensitivity of 0.8311 mu A/mu M. Using the method of multiple standard addition, aquaculture water fortified with 0.5 mu M and 0.75 mu M malachite green provided mean recoveries of 78.79% and 87.20% with coefficients of variation of 2.07% and 1.45%. Therefore, analytical figures of merit suggest that this method provides rapid, simple, economical, and precise determination of malachite green in aquaculture water.