Abstract:In order to solve the problem that Cr(III)-organic complex will interfere with the determination of hexavalent chromium in polluted sites such as leather making, by optimizing the chromatographic conditions of the instrument and improving the pretreatment method on the basis of the existing standard, an ultra-trace hexavalent chromium analyzer is used to detect hexavalent chromium.??The influence of trivalent chromium, chroma and Cr(III)-organic complex on the determination of hexavalent chromium was investigated by adding low, medium and high concentrations of trivalent chromium, hexavalent chromium and Cr(III)-organic complex in soil.??The results showed that the optimal chromatographic conditions were as follows: the concentration of mobile phase was 0.1 mol/L, the pH of mobile phase was 9, the dosage of concentrated sulfuric acid was 5 mL, the flow rate of mobile phase was 1.2 mL/min, and the flow rate of derived reagent was 0.7 mL/min.??The pretreatment method of samples was improved from filtration extraction to centrifugal extraction, and the pH of samples did not need to be adjusted before loading, which could improve the detection efficiency.??Compared with the current standard, this method is simple and short in operation. It is free from the interference of chromium trivalent, sample chrominance and Cr(III)-organic complex.??The precision and accuracy of the method were significantly improved, the relative standard deviations were 1.7%~5.2%, and the recoveries were 94.6%~103%. The results were statistically tested by liquid chromatography-inductively coupled plasma mass spectrometer, and the results showed no significant difference.??The method is suitable for the determination of hexavalent chromium in the fields rich in Cr(III)-organic complexes such as tannery and electroplating.