Detection Of Heavy Metal Chromium In Foods

With economic development and industrial technology progress, now a lot of harmful heavy metals has been discharged into the soil environment. It affects food quality decline, and endangers human health through the food chain. Therefore it has important theoretical and practical significance to establish a method for detection of trace heavy metals in food. This paper established a method differential pulse stripping voltammetry for the determination of heavy metal chromium in foods, combined with the sample pretreatment of wet digestion that is suitable for on-site rapid detection. Finally we made a determination method that was nitric acid-hydrogen peroxide wet digestion-electrochemical method, Compared with the microwave digestion atomic absorption method.This paper conducted six aspects of research work, the research results are as follows:1) The pre plating mercury film technology was used on the glassy carbon electrode. We determined the influence law of peak current of chromium when the glassy carbon electrode with mercury film plated, and determined the frequency and effect of using the mercury film electrode by experiment;2) Heavy metal chromium was determined by using differential pulse stripping voltammetry. The electrochemical parameters of chromium were optimized by Reference600 workstation and trace element analyzer, and the feasibility of using trace element analyzer for electrochemical detection of chromium was proved;3) The pretreatment of heavy metal chromium in food used nitric acid- hydrogen peroxide digestion technology. The optimal wet digestion solution of heavy metals chromium in food was studied. Experimental conditions were determined. Preliminary digestion time was 0 h, and digestion temperature was 130 ℃, and nitric acid of 65~68% was10 mL, and hydrogen peroxide of 30% was 38mL;4) The problem of the convergence of the nitric acid- hydrogen peroxide wet digestion-electrochemical method was determined, and the peak effect was the best when the pH value was alkalescency;5) The feasibility of the experimental scheme was determined by the determination of various food products, and the reliability of the scheme was determined by comparison with the microwave digestion- atomic absorption method;6) The nitric acid- hydrogen peroxide wet digestion- electrochemical determination method was established, and the detection limit was 2.5 × 10-6g/L.