Fast and ultrasensitive trace malachite green detection in aquaculture and fisheries by using hexadecylpyridinium bromide modified electrochemical sensor

An ultrasensitive voltammetric method for fast determination of trace malachite green in aquaculture and fisheries using an acetylene black paste electrode modified with hexadecylpyridinium bromide was established. Compared with the unsatisfactory response at carbon paste electrode, the performance of the modified electrode for the electrooxidation of malachite green was improved significantly. The parameters for quick and sensitive detection of malachite green were optimized, including the type of supporting electrolyte, solution pH, accumulation potential and accumulation time. By using the technique of second derivative linear sweep voltammetry, the peak current was linearly related to malachite green concentration in the wide range of 0.02 mu M - 40 mu M. After a 150 s preconcentration, a low method detection limit of 4.0 nM was obtained (Signal to noise ratio of 3). In addition, the hexadecylpyridinium bromide modified acetylene black paste electrode exhibited excellent intra-day repeatability (RSD = 2.7 %) and inter-day repeatability (RSD = 3.8 %), good stability and antiinterference ability. Finally, the method was applied to the determination of malachite green in water and fish samples with satisfied relative recoveries of 96.0-104.0 %, suggesting that this method has good accuracy.