Simultaneous determination of selenium and germanium in soil by mixed acids digestion and hydride generation-atomic fluorescence spectroscopy
YANG Xiaobin, ZHANG Xin, WEN Jiaming, CHEN Aili
Research Institute No. 230, CNNC, Changsha 410007, China
摘要：建立混合酸溶样氢化物发生-原子荧光光谱法同时测定土壤中硒和锗的方法。试样经硝酸、氢氟酸、高氯酸、浓硫酸消解，在磷酸介质中与硼氢化钾进行反应，利用原子荧光光谱法测定其中的硒和锗。最佳分析条件：原子化器高度为8 mm；灯电流硒、锗均为80 mA；光电倍增管负高压为270 V；载气流量为300 mL/min；屏蔽气流量为800 mL/min；氢化物发生的还原剂为20 g/L硼氢化钾-5 g/L氢氧化钾的混合液；选用10%的磷酸溶液作为载流液。硒与锗的线性范围分别为0～20，0～100 μg/L，检出限分别为0.010，0.020 mg/kg。对不同硒、锗含量的土壤国家标准物质进行测定，测定值的相对标准偏差分别为0.19%～3.68%，0.64%～2.70%(n=6)，相对误差分别为-5.38%～5.01%，-4.83%～2.43%。该方法线性范围宽，检出限低，准确度高，精密度好，干扰少，适用于大批量土壤样品中硒和锗的同时测定。
Abstract：A method for simultaneous determination of selenium and germanium in soil by mixed acids digestion and hydride generation-atomic fluorescence spectroscopy was developed. After being digested by nitric acid, hydrofluoric acid, perchloric acid, and concentrated sulfuric acid, the sample reacted with potassium borohydride for hydride in phosphoric acid medium, selenium and germanium in which were determined by atomic fluorescence spectroscopy. The determination conditions were optimized as followings: atomizer height was 8 mm, the currents were all 80 mA for selenium and germanium lamp, negative pressure of photomultiplier tube was 270 V, carrier gas flow was 300 mL/min, shielding gas flow was 800 mL/min, 20 g/L potassium borohydride-5 g/L potassium hydroxide solution was selected as reduction agent, and 10% phosphoric acid was used as carrier fluid. The linear ranges of selenium and germanium were 0-20, 0-100 μg/L, and the detection limits were 0.010, 0.020 mg/kg. Simultaneous determination of selenium and germanium was carried out on different levels of soil national standard substance, the relative standard deviations of Se and Ge were 0.19%-3.68%, 0.64%-2.70%(n=6) with the relative errors of -5.38%-5.01%, -4.83%-2.43%. The method has advantages of wide linear range, low detection limit, high accuracy, good precision, and little interference, and it is suitable for the determination of selenium and germanium in large-scale soil samples.
Keywords：mixed acids digestion; atomic fluorescence spectroscopy; selenium; germanium; simultaneous determination