Microdetermination of Chromium(VI) in Natural Water with a Piezoelectric Crystal Detector

In this paper,a piezoelectric method proposed for the microdetermination of chromium(Ⅵ).The method was based on the redox reaction of chromium(Ⅵ) with iodide,the iodine produced from the reaction was extracted by CCl4,and the frequency change of the piezoelectric crystal caused by the inborned iodine was measured,then chromium(Ⅵ) could be determined indirectly.The linear response could be obtained within the concentration of 0.013～3.8mg/L chromium(Ⅵ) and the regression equation was △f=2.6+4.3×103C(mg/L),with the correlation coefficient of 0.995.The method is very simple and it has been applied to determine chromium(Ⅵ) in natural water.