在盐酸浓度为3.0 mol·L-1介质中,Cr(Ⅵ)把As(Ⅲ)氧化成As(Ⅴ),利用氢化物发生-原子荧光光谱法(HG-AFS)测定剩余As(Ⅲ)的含量,间接得到Cr(Ⅵ)的含量.基于相同原理,结合高锰酸钾氧化Cr(Ⅲ)来测定Cr(Ⅲ)含量.研究了溶样方法和共存离子可能引起的干扰,优化了仪器工作条件、酸度及其他影响因素.在最佳条件下,铬含量在4.0～20μg·L-1范围内线性关系良好,方法检出限为2.5μg·L-1；将方法应用于牛奶样品分析,相对标准偏差(RSD,n=6)为1.6％～2.7％.加标回收率为96.5％～104.2％.%In the medium of 3 mol · L-1 hydrochloric acid,Cr(Ⅵ) oxidized As(Ⅲ) to be As(Ⅴ),the As(m) content,which was left over,was determined by hydride generation-fluorescence spectrometry,giving that it was inversely proportional to Cr(Ⅵ) content.Based on the same principle and combined with potassium permanganate oxidation of Cr(Ⅲ) to be Cr(Ⅵ),the Cr(Ⅲ) was,therefore,determined.The sample digestion procedures and co-existing ions which might have interference were investigated.The instrumental operation parameters,reaction acidity and other influence factors were studied.Under optimum operation conditions,a good linear relationship was obtained in the range of 4.0～20 μg · L-1 Cr.The detection limit of the method was 2.5 μg · L-1.When the method was applied to milk analysis,a relative standard deviation(RSD,n=6) of 1.6％～ 2.7％ was found.The recovery was 96.5％～104.2％.
展开▼
