硫脲络合–火焰原子吸收光谱法测定低硅铝合金中的银含量

Determination of the Silver Content in Low Silicon Aluminium Alloys with Thiourea by Flame Atomic Absorption Spectrometry

采用硫脲络合-火焰原子吸收光谱法测定低硅铝合金中的银元素含量。实验探讨了酸度及硫脲用量对银测定的影响及铝合金中基体元素与共存元素对银元素分析线的干扰情况。结果表明：选用9%的盐酸和3%的硝酸溶解试样最好，加入5 mL 50 g/L硫脲溶液可消除氯离子对试验结果的影响，基体铝元素和其它共存元素不干扰银的测定。根据低硅铝合金中银元素的含量范围，合成系列标准溶液，建立工作曲线，工作曲线的线性范围为0.05%～0.50%。银元素含量为0.30%的样品测定结果的相对标准偏差为0.15%（n=8），标准加入回收率为96.8%～98.5%。该方法操作简便、重现性好、测量结果准确可靠。

The silver content in the low silicon aluminium alloys was determined by flame atomic absorption spec-trometry with thiourea. The influence of acidity and the dosage of thiourea on the silver determination were discussed through experiments. The interferences from matrix element and coexist elements to the analytical line were discussed. The results showed that the optimal hydrochloric acid and nitric acid volume concentration were confirmed. The effect of chlo-rine was eliminated with 5 mL 50 g/L thiourea solution. There was no influence on the determination of silver either the matrix element aluminium or the coexist elements. The standard curve was established according to the content of silver in the low silicon aluminium alloys, and the linear range of the standard curve was 0.05%-0.50%. For samples contained 0.30%silver, the relative standard deviation was 0.15%（n=8）, and the addition standard recovery was in the range of 96.8%-98.5%. The method is simple to operate, it has good repeatability and accuracy.