Abstract:Objective: Aim of this study was to establish an electrochemical method for rapid detection of Cd in high water vegetables. Methods: The modification of carbon paste electrode was optimized by adjusting the doping ratio of nano-alumina/bismuth oxide. After analyzing the influence of each substrate on the detection, the dilution ratio of the substrates and the detection conditions were determined. Based on the content of main metal elements in the matrix, the influence of major interfering ions was analyzed. Result: The doping ratio of alumina/bismuth oxide was 20%. Linear range of Cd detection was 0.2-70 μg/L by using this doped modified carbon paste electrode (DMCPE) through square wave anodic stripping voltammetry (SWASV), and the linear equation was as follows: Ip=0.1774C+0.3646 with correlation coefficient r=0.9983. The recoveries were 87.45%-101.14% in the detection of Cd when the dilution ratios of cucumber, tomato and cabbage were 30, 60 and 100, respectively. The influence of matrix on Cd detection was as follows: cabbage > tomato > cucumber. High content of Zn2+ and Mg2+ in vegetables interfered with the electrochemical detection of Cd, among which, Zn2+ interfered the most. The test value by SWASV method reached 87.25%-108.25% of ICP/MS detection. Conclusion: After homogenation-HNO3 dilution-ultrasonic extraction, Cd in vegetable samples can be determined accurately and quickly by this DMCPE-SWASV method. The results of this study provided a reference for development of low-cost, stable and easy-to-operate rapid detection technology for heavy metals in agricultural products.