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本法采用二苯碳酰二肼试剂在酸性条件下与六价铬反应.生成二苯碳酰二肼铬,化合物呈紫红色。在波长540nm处有最大吸收峰。对总铬测定则采用高锰酸钾氧化,使铬全部转化为六价,然后再与二苯碳酰二胼反应。实验在大量钙、镁、硫酸根、硝酸根,铵根,以及ppm级的砷、铅、镉、汞、铝、铜、铁、锰、硅、氟等离子存在下测定铬无干扰,测定铬范围为0.020—0.200mg/l,精密度±5％。样品重加回收率95-105％,对样品稍加处理便能测定,方法简便。
This method uses diphenylcarbazine hydrazide reagents under acidic conditions with hexavalent chromium reaction generated diphenylcarbazide chromium, the compound was purple. The wavelength of 540nm at the maximum absorption peak. The determination of total chromium using potassium permanganate oxidation, so that all chromium into hexavalent, and then with the diphenylcarbinazepine reaction. The experiments were performed to determine chromium in the presence of large amounts of calcium, magnesium, sulfate, nitrate, ammonium and ppm of arsenic, lead, cadmium, mercury, aluminum, copper, iron, manganese, 0.020-0.200mg / l, precision ± 5%. The sample re-collection rate of 95-105%, the sample can be measured with a little treatment, the method is simple.