火焰原子吸收光谱法次灵敏线的选择及其在工业硫酸锌溶液中镁测定的应用

Selection of hyposensitive line in flame atomic absorption spectrometry and its application in the determination of magnesium in industrial zinc sulfate solution

以Mg202．6nm次灵敏线为分析线，2％盐酸为酸介质，5mL50mg／mL硝酸镧溶液为释放剂，建立了火焰原子吸收光谱法（FAAS）测定工业硫酸锌溶液中高含量镁的方法。实验表明，镁的质量浓度在1．0～30．0μg／mL范围内呈良好的线性关系，所得校准曲线方程为A=0．028p（μg／mL）＋0．0043，相关系数为R2=0．9998。方法检出限为0．15μg／mL。实验表明，控制样品溶液稀释倍数大于320时，工业硫酸锌溶液中其他元素均不干扰镁的测定。采用实验方法测定实际工业硫酸锌溶液中镁，测定平均值为5．67mg／mL，相对标准偏差（RSD，n=5）为1．7％。采用实验方法与EDTA滴定法对工业硫酸锌溶液进行对照分析，所得结果基本一致，实验方法的加标回收率在96％～104％范围内。

A determination method of high content magnesium in industrial zinc sulfate solution by flame a- tomic absorption spectrometry （FAAS） was established. The hyposensitive line of Mg 202.6 nm was used as analytical line, 2 % hydrochloric acid was used as determination medium, and 5 mL of 50 mg/mL lantha- num nitrate solution was used as releasing agent. The results showed that the linear relationship was good when the mass concentration of magnesium was in range of 1.0-30.0 μg/mL. The calibration curve was A=0. 028 p （μg/mL）＋0. 004 3 with correlation coefficient of R2 =0. 999 8. The detection limit of method was 0.15 μg/mL. The experiments indicated that other elements in industrial zinc sulfate solution did not interfere with the determination of magnesium when the dilution ratio of sample solution was higher than 320. The proposed method was applied to the determination of magnesium in actual industrial zinc sulfate solution. The average value was 5.67 mg/mL, and the relative standard deviation （RSD, n= 5） was 1.7 %. The industrial zinc sulfate solution was determined by the experimental method and EDTA titration method, and the found results were basically consistent. The recoveries of standard addition were between 96% and 104%.