巯基棉富集-石墨炉原子吸收测定生活饮用水中痕量铊

Determination of trace thallium in drinking water samples by GFAAS with sulfhydryl cotton concentration

目的改进国家标准检验法水样前处理方法,建立巯基棉富集-石墨炉原子吸收测定生活饮用水中痕量铊的分析方法。方法水样用氨水(1+9)调节其pH值至9,以5 ml/min流速使水样通过巯基棉,巯基棉用(1+5)硝酸小火加热微沸解吸,上清液用石墨炉原子吸收分析。结果在优化的条件下,方法的线性范围为0μg/L^50μg/L,线性相关系数0.9992,最低检测质量浓度为0.01μg/L,回收率为91.5%~97.6%,RSD为4.3%~8.3%。结论方法操作简便,减少了污染,富集时间大为缩短;灵敏度高,满足国家卫生标准规定的饮用水中铊限量值(为0.1μg/L)需要。适合于没有电感耦合等离子体质谱分析仪的基层实验室开展饮用水中铊元素的定量分析。

Objective To improve the water sample pretreatment method of national standard examination methods,and establish a method for determination of trace thallium in drinking water by graphite furnace atomic absorption spectrometry（GFAAS）with sulfhydryl cotton concentration.Methods The water sample was adjusted pH to 9 with ammonia water（1 ＋ 9）,then passed though sulfhydryl cotton tube at a flow rate of 5 ml /min.Thallium in water sample was desorbed using（1 ＋ 5） nitric acid as an eluent.After pretreatment,the sample was analyzed by GFAAS.Results Under the optimized operation conditions,the method has a good linearity in the range of 0 μg /L - 50 μg /L with a correlation coefficient（r） of 0.9992.The minimum detection concentration of the method was 0.01 μg /L,and the recoveries were from 91.5% to 97.6%,with relative standard deviations（RSD） from 4.3% to 8.3%.Conclusion The proposed method can greatly shorten the time of concentration and reduce pollution in the procedure of sample pretreatment.It is easy to operate and has high sensitivity,which can meet the limiting value of thallium（0.1 μg /L） set by the national standards for drinking water quality.The method is suitable for determination of trace thallium in drinking water in basic laboratories without ICP equipment.