原子荧光法测定艾氏卡试剂熔样中砷的含量

Determination of As in Eschka reagent melting sample by atomic fluorescence spectrometry

目的通过优化进口无烟煤和烟煤前处理条件,确定最佳前处理方法。方法采用王水法、微波消解法、艾氏卡法对进口无烟煤和烟煤进行前处理,原子荧光法对煤中砷含量进行检测。结果对烟煤来说3种前处理方法的砷含量测定结果无大差异,但对无烟煤来说,王水法、微波消解法的砷含量测定结果较艾氏卡法严重偏低。在艾氏卡法中,升温速度对无烟煤砷含量测定结果几乎没有影响;但会随着升温时间的增加,部分烟煤的砷含量测定结果逐渐升高;1.5 h室温升至500℃、在800℃下保持3 h能满足大多数进口无烟煤、烟煤样品的需要;艾氏卡试剂会带来一定的基质增强效应,使用基质校准曲线可进行准确定量。结论艾氏卡法对进口烟煤和无烟煤前处理效果较王水法、微波消解法有明显优势,适用于进口烟煤和无烟煤的前处理。

Objective To establish the optimal pretreatment method for imported anthracite and bitumite by optimizing the pretreatment conditions. Methods The methods of aqua regia,microwave digestion and Eschka methods were used to pretreat the imported anthracite and bitumite and the atomic fluorescence spectrometry was adapted as the detection method. Results For bituminous coals,there is no obvious difference in the determination results with the three different methods,but for anthracite samples,the results of using microwave digestion and aqua regia methods were significantly lower than that of using the Eschka method. With Eschka method,heating rate had nearly no influence on the results for anthracite,but for some bituminous coal,the results gradually increased as the heating time increased. Increasing the temperature from room temperature to 500 ℃ in 1. 5 h and then maintaining the temperature under 800 ℃ for 3 h could meet the requirements for most imported anthracite and bitumite samples. To a certain degree,Eschka reagent might bring matrix enhancement effect,which could be eliminated by using the matrix calibration curve and get accurate results. Conclusions The Eschka method had obvious advantages over the aqua regia and microwave digestion method. It could be used as a pretreatment method to pretreat imported anthracite and bitumite.