气体浮选预富集与火焰原子吸收光谱法联用测定复杂基体样品中痕量重金属(英文)

Gas flotation preconcentration combined with flame atomic absorption spectrometry for detection of trace heavy metals in complex matrix samples

水溶液中痕量金属离子、碘阴离子和亚甲基蓝(C_(16)H_(18)ClN_3·3H_2O,MB)形成疏水性三元缔合物([MI_(n+1)]^-[MB]^+)。通过气体浮选使得复杂基体样品如高盐度工业废水、海水和工业浓硫酸中痕量金属元素(Ag,Cu,Cd,Pb)分离预富集。三元配合物由高纯氮气带入5 mL甲苯溶剂中,甲苯溶液直接应用于火焰原子吸收光谱(FAAS)测定。研究了溶液pH值、KI和MB体积,以及收集试剂种类对分离预富集的影响,并得到了优化操作参数。对含分析物浓度为200 ng/mL的水溶液,其富集倍数与水和有机试剂的体积比几乎相同。Cu,Pb,Cd和Ag的检出限分别为0.9,0.8,0.5和0.4 ng/mL。研究了共存元素的干扰。该方法应用于模拟海水和工业浓硫酸中痕量Cu,Pb,Cd和Ag的测定,平均回收率分别在90%—93%和80%—92%之间。

A ternary association complex [MIn＋1 ]^-[MB]^＋ formed by metals （M^n＋）, iodine anion （I^-） and basic dye methylene blue （C16H18 ClN3S·3H2O, MB） was applied in the preconcentration of trace heavy metals （Ag, Cu, CA, Pb） in complex matrix samples, such as high salty solution and commercial sulfuric acid, by gas flotation. The ternary association complex was floated and absorbed by 5 mL of toluene, and the toluene phase was directly determined by the flame atomic absorption spectrometry （FAAS）. Several parameters, including flotation pH, volume of KI and methylene blue solution, and selection of organic solvent were studied. Under the optimum conditions, the enrichment factor for the concentration level of analytes 200 ng/mL was almost equal to the ratio of the aqueous solution volume to organic solvent volume. The detection limits for Cu, Pb, CA and Ag were 0. 9, 0. 8, 0. 5 and 0. 4 ng/mL, respectively. The interference of coexistent elements on the determination were also studied. The developed method was applied in the determination of trace Cu, Pb, CA and Pig in artificial seawater and commercial sulfuric acid samples with the average recoveries of about 90%- 93% and 80%- 92%, respectively.