石墨炉原子吸收光谱法测定锡锭中痕量铝

建立了石墨炉原子吸收光谱法测定锡锭中痕量铝的方法，确定了样品分解方式和石墨炉原子吸收光谱测定铝的最佳条件。以盐酸-过氧化氢（V（盐酸）∶V（过氧化氢）= 2.5∶1.5）分解样品，在16 g/L柠檬酸、0.12 mol/L盐酸介质中，以4 g/L硝酸钙为基体改进剂进行铝的测定。结果表明：在选定的酸度介质中，不需要挥锡，锡不会水解，样品溶液保持清亮时间长；硝酸钙提高了测铝的灵敏度，并增强了抗氯化物干扰的能力；样品中锡及共存元素不干扰测定。该方法的检出限为2.96 μg/L，线性范围为0～100 μg／L，相关系数r≥0.998 0。方法用于锡锭中铝的测定，相对标准偏差为6.6%，回收率在100%～119%之间，样品测定值与标准加入法及ICP-AES法测定值相符。

Determination of trace aluminum in tin ingot by graphite furnace atomic absorption spectrometry

A method for the determination of trace aluminum in tin ingot by graphite furnace atomic absorption spectrometry was established. The sample decomposition ways and the optimal conditions of determining aluminum by graphite furnace atomic absorption spectrometry was confirmed. Sample was dissolved in hydrochloric acid and hydrogen peroxide(V (hydrochloric acid)∶V (hydrogen peroxide) = 2.5∶1.5). Aluminum was determined in 16 g/L citric acid and 0.12 mol/L hydrochloric acid medium with 4 g/L calcium nitrate as matrix modifier. The results showed that in the selected acidity medium, it was not necessary to volatilize tin that will not be hydrolyzed, and the sample solution was kept clear for a long time. Calcium nitrate improved the measurement sensitivity of aluminum and enhanced resistance to chloride interference. Tin and coexisting elements in sample did not interfere in the determination. The detection limit of this method was 2.96 μg/L. The linear range was between 0 μg/L and 100 μg/L. The correlation coefficient r was not less than 0.998 0. The relative standard deviation for the determination of aluminum in tin ingots was 6.6%, recovery rate was between 100 % to 119%, and the measured values of sample were consistent with that of the standard addition method and ICP-AES.