Determination of methylmercury by differential pulse voltammetry with gold microelectrode

Abstract

Methylmercury is a kind of fatal neurotoxin. It is of great importantance to establish a sensitive and rapid method to detect its content for the daily environmental monitoring. We propose a new method for direct determination of methylmercury by the differential pulse voltammetry with gold microelectrode and analyze the electrochemical behavior of methylmercury by this method. Meanwhile, we conduct comparative experiments by the differential pulse voltammetry with glassy carbon electrode. The results show that under the same experimental conditions, the gold microelectrode is more sensitive to methylmercury, and its minimum detection concentration reaches 0.10 μg/L. Under the optimal experimental parameters (pH=5.0, deposition potential of -0.80 V and deposition time of 800 s) , the linear range of methylmercury concentration detection by the gold microelectrode method is 0.05-0.50 μg/L, the sensitivity is 0.354 nA/(μg·L), and the minimum limit of detection is 0.012 μg/L, which is far lower than the standard detection value given by the World Health Organization (1.0 μg/L). In addition, the electrochemical sensor based on gold microelectrode shows good selectivity for methylmercury with the advantages of simple operation, low detection limit, high stability and good anti-interference performance. The gold microelectrode method provides a new platform for the trace detection of methyl mercury.