饮用水中微量铝的3种检测方法比较

Comparison of three methods for determining trace aluminum in drinking water

目的：对饮用水中的微量铝采用水杨基荧光酮-氯代十六烷基吡啶分光光度法（简称＂SAF法＂）、电感耦合等离子体发射光谱（inductively coupled plasma-atomic emission spectrometry,ICP-AES）法和流动注射分析（flow injection analysis,FIA）法3种方法进行检测。方法 ：SAF法按照GB/T 5750.6—2006中的水杨基荧光酮-氯代十六烷基吡啶分光光度法进行操作;ICP-AES法采用轴向观测方式,同时采用同心雾化器加玻璃旋流雾化室,水样经酸化后直接进样分析,采用外标法定量;FIA法是在六亚甲基四胺缓冲溶液（pH=6.0）中,以邻菲啰啉盐酸盐溶液为掩蔽剂,使铝离子与铬天青S反应生成络合物,在550 nm波长下进行流动注射分析。结果：SAF法的线性范围为0~120μg/L,相关系数为0.999 1,检出限为20μg/L,相对标准偏差为2.8%~8.2%,回收率为91.1%~108%;FIA法的线性范围为10~200μg/L,相关系数为0.999 5,检出限为3.0μg/L,相对标准偏差为2.4%~4.4%,回收率为95.8%~103%;ICP-AES法的线性范围为5~200μg/L,相关系数为0.999 4,检出限为1.0μg/L,相对标准偏差为1.8%~3.6%,回收率为96.5%~101%;SAF法和FIA法测定铝时会受水样中其他阳离子的干扰,而ICP-AES法在水样主要基体元素存在下测定不存在干扰;采用3种方法对不同批号参考样的测定结果一致。结论：SAF法的回收率与精密度均逊于另外2种方法,而ICP-AES法的检出限最低、操作最简便、抗干扰能力最强,用其测定饮用水中的微量铝更好。

Objective To compare three methods for determining trace aluminum in drinking water,including SAF,ICP-AES and FIA.Methods SAF was performed following the national standard method in GB/T 5750.6-2006 for SAF.ICP-AES was carried out with axial observation,concentric nebulizer and glass cyclonic spray chamber,and the water sample was analyzed after acidification with external standard method for quantification.For FIA,in hexamine buffer solution（pH =6.0） with phenanthroline as anti-interference agent,aluminum reacted with chromazurol S solution and a compound,whose maximum absorption was at 550 nm,was formed.Results For SAF,linear range was between 0 and 120 μg/L,the correlation coefficient was 0.999 1,the detection limit was 20 μg/L,the range of relative standard deviations（n=6） was between 2.8% and 8.2%,and the recovery rate was from 91.1%to 108%.For FIA,linear range was between 10 and 200 μg/L,the correlation coefficient was0.999 5,the detection limit was 3.0 μg/L,the range of relative standard deviations（n6） was from 2.4% to 4.4%,and the recovery rate was from 95.8%to 103%.For ICP-AES,the linear range was between 5 and 200 μg/L,the correlation coefficient was 0.999 4,the detection limit was 1.0 μg/L,the range of relative standard deviations（n=6） was between 1.8%and 3.6%,and the recovery rate was from 96.5% to 101%.Conclusion The detection limit of ICP-AES is the lowest,while its operation is the most simple.The recovery rate and precision of SAF are inferior to the other two methods.