以制备的硫代乙酰胺键合硅胶为微柱填充材料,建立酸性条件(pH 1 0)下流动注射微柱选择性预富集,0.6 mol/L硫脲溶液洗脱,火焰原子吸收测定环境样品中痕量铜的方法。流动注射在线固相萃取的最佳采样流速为8.0 mL/min;最佳洗脱流速为5.0 mL/min,时间为60 s。在优化的条件下,采样体积为10和50 mL时,线性范围分别为2.0~100.0μg/L和0.5~30.0μg/L;检出限(3σ)分别为0.36和0.07μg/L;富集倍数分别为80和170;相对标准偏差分别为(n=9)3.5%和2.0%。研究了环境样品中常见阴阳离子对测定的干扰。应用于灌木枝叶样品(GBW07602)、标准模拟水样(GBW08608)样品和环境样品中铜的分离与富集,取得满意结果。
A selective and sensitive on-line preconcentration procedure was developed for the determination of trace levels of copper(Ⅱ) by flame atomic absorption spectrometry(FAAS).A mini-column packed with a silica gel functionalized with thioacetamide was used for the on-line selective enrichment of copper(Ⅱ) at pH 1.0.The copper(Ⅱ) was eluted with 0.6 mol/L thiourea solution and determined by FAAS.Some important flow injection variables affecting preconcentration were optimized(sample flow rate was 8.0 mL/min,eluent flow rate was 5.0 mL/min and elution time was 60 s).Under the optimum conditions,linear calibration graphs over the concentration ranges of 2.0—100.0μg/L and 0.5—30.0μg/L;detection limits of 0.36 and 0.07μg/L;preconcentration factor of 80 and 170 were obtained for the preconcentration volumes of 10.0 and 50.0 mL of copper(Ⅱ) solutions,respectively. The relative standard deviations for 9 replicate determinations of copper(Ⅱ) were 3.5%and 2.0%at same conditions,respectively.The effect of the presence of various species commonly associated with environmental samples was also investigated.The method has been successfully applied to the selective determination of the trace Copper in standard reference materials(GBW07602,GBW08608 with satisfactory results.