氢化物发生-原子荧光光谱法同时测定锡矿石中砷和锑

Determination of arsenic and antimony in tin ore by hydride generation-atomic fluorescence spectrometry

通常锡矿石中砷、锑含量的检测方法都是以分光光度法为主，实验以盐酸-硝酸混合酸微波消解样品，建立了氢化物发生一原子荧光光谱法测定锡矿石中砷和锑的新方法。实验表明：以8mL盐酸-硝酸（5＋3）混酸为溶剂，采用微波消解样品，在盐酸浓度约为O．96mol／L，硫脲和抗坏血酸的质量浓度均为10a／L时，以HCI（1＋9）作为载流液，20a／L硼氢化钾溶液为上机还原剂进行测定，以砷和锑的荧光强度与其对应的质量浓度绘制校准曲线，线性相关系数均不小于O．9998。砷和锑的方法检出限分别为0．0442μg／L和0．0204μg／L。干扰试验表明，锡矿石样品中的共存元素不干扰测定。采用实验方法对锡矿石实际样品中砷和锑进行测定，测得结果的相对标准偏差（RSD，n=6）分别为1．1％～1．3％和O．99％～1．4％，加标回收率分别为99％～104％和98％～104％。将实验方法应用于锡矿石标准物质的测定，测定值与认定值基本一致。

The determination method of arsenic and antimony in tin ore usually adopts spectrophotometry.A new determination method of arsenic and antimony in tin ore by hydride generation-atomic fluorescence spectrometry was established after the sample was dissolved in hydrochloric acid-nitric acid by microwave digestion.The results showed that the sample could be dissolved by microwave digestion with 8 mL of mixed hydrochloric acid-nitric acid(5+3)as solvent.When the concentration of hydrochloric acid was about 0.96mol/L,the mass concentration of both thiourea and ascorbic acid were 10g/L,HCl(1+9)was used as carrier liquid,and 20g/L potassium borohydride solution was used as reducing agent,the calibration curves were plotted based on the fluorescence intensity of arsenic and antimony against the corresponding mass concentration.The linear correlation coefficients were both not less than 0.999 8.The detection limit of arsenic and antimony was 0.044 2μg/L and 0.020 4μg/L,respectively.The interference test showed that the coexisting elements in tin ore sample did not interfere with the determination.The proposed method was applied to the determination of arsenic and antimony in tin ore actual samples.The relative standard deviation(RSD,n=6)was 1.1%-1.3%and 0.99%-1.4%,respectively.The recoveries were99%-104% and 98%-104%,respectively.The certified reference materials of tin ore were determined by the experimental method.The results were basically consistent with the certified values.