等离子光谱法测定城市污泥中总镉、总铬的方法改进

Improvement on Method for Determination of Total Cadmium and Total Chromium in Municipal Sludge by ICP-AES

目前检测城市污泥中总镉、总铬的标准方法为《城市污水处理厂污泥检验方法》（CJ／T 221—2005），该方法样品消解时间长、酸用量大，为此改进了样品消解方法，分别采用HNO3-H2O2常压消解、HNO3-H2O2微波消解法处理污泥样品，然后采用等离子光谱法检测污泥中的总镉、总铬。与标准方法的对比试验结果表明，两种方法的相对偏差为0．8％～7．2％。改进的常压消解法的加标回收率：总镉为98．5％～105％，总铬为94．2％～95．6％；微波消解的加标回收率：总镉为104％～106％，总铬为98．5％～102％；改进方法的检出限：总镉为0．00075mg／L，总铬为0．0023mg／L。

The methods for determination of total cadmium and total chromium in municipal sludge issued in the Determination Method for Municipal Sludge in Wastewater Treatment Plant （CJ/T 221 - 2005） have longer digestion time and large acid consumption. Therefore, the conditions of digestion were improved by using an atmospheric pressure digestion method （adding HNO3 -H2O2） coupled with ICP- AES and a microwave- assisted-ICP-AES method （adding HNO3 -H2O2） to determine total cadmium and total chromium in sludge samples. Compared with the standard methods, the relative deviation of the two methods mentioned above is from 0.8% to 7.2%. The recovery of the determination of total cadmium by using atmospheric pressure digestion method is between 98.5% and 105%, and that of total chromium is between 94.2% and 95.6%. The recovery rate with standard addition of determination of total cadmium by using microwave-assisted-ICP-AES method is between 104% and 106% , and that of total chromium is between 98.5% and 102%. The minimum detection limit of total cadmium is 0. 000 75 mg/L, and that of total chromium is 0. 002 3 mg/L.