摘要:
采用微波消解对样品进行前处理,建立了氢化物发生-双道原子荧光光谱同时测定化肥中砷和汞的方法。以20 g/L KBH4为还原剂,8%的盐酸为载液,测定砷和汞的负高压均为270 V,砷的灯电流为60 mA,汞的灯电流为20 mA。讨论了常见元素对测定的干扰,40 g/L的主量元素N、P、K,10倍于砷、汞浓度的杂质元素Te、Ca、Zn、Cu、Cr、Mn、Ni、Sb、Sn、Pb对砷和汞测定的影响满足分析要求。方法测定砷和汞的线性范围As为0.68~100 μg/L,Hg为0.12~10 μg/L;检出限As为0.68 μg/L,Hg为0.12 μg/L;方法精密度(RSD,n=5)低于8%。该方法具有前处理简便快速、易于操作、灵敏度高等特点,能满足化肥中砷和汞同时测定的要求。
关键词:
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化肥
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砷
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汞
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微波消解
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氢化物发生
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原子荧光光谱法
Abstract:
A method for the determination of As and Hg in fertilizer by hydride generation-two-way-atomic fluorescence spectrometry has been established using the pretreatment by microwave digestion technique. 20 g/L KBH4 for reductant and 8% HCl for carrier fluid. Optimal instrument conditions were HV of -270 V for As and Hg measurements with As lamp current of 60 mA and Hg lamp current of 20 mA. Interference from common elements in the determination of As and Hg are discussed in this paper. The effect of the main elements of N, P and K (40 g/L) and impurity elements of Te, Ca, Zn, Cu, Cr, Mn, Ni, Sb, Sn and Pb, which was ten times those of As, Hg, met the requirements of analytical chemistry. The method for determination of As and Hg had a wide linear range of 0.68-100 μg/L and 0.12-10 μg/L, respectively. The detection limits for As and Hg were 0.68 μg/L and 0.12 μg/L, respectively. The method was applied to determine real sample and the RSD (n=5) for As in phosphate fertilizer was 4.22% and 7.53% in potash fertilizer, the RSD (n=5) for Hg in phosphate fertilizer was 5.89% and 4.41% in potash fertilizer. This method is rapid and simple with a high accuracy and sensitivity, and can be applied to measure As and Hg in nitrogen fertilizer, phosphate fertilizer and potash fertilizer, providing a reference for correlated detection departments to monitor the quality of the fertilizer.
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