双水相气浮溶剂浮选与火焰原子吸收光谱法联用分析环境中Cd(Ⅱ)

Aqueous two-phase gas solvent sublation and flame atomic absorption spectrometric analysis of trace Cd(Ⅱ) in the Environment

结合气浮溶剂浮选和双水相萃取(ATPE)的优点,建立了一种新的分离/富集的方法,双水相气浮溶剂浮选(ATGS),并用于环境中痕量Cd(Ⅱ)的分离/富集.同时,以火焰原子吸收光谱(FAAS)检测Cd(Ⅱ),考察了浮选时间、N2流速、丙醇的分相条件、pH和配合剂用量等因素对浮选Cd(Ⅱ)的影响.最后优化出最佳浮选条件和测定条件,并探讨了共存离子对Cd(Ⅱ)浮选的干扰情况.结果表明,2mol·L-1的KI9.5mL,1g·L-1的罗丹明B2.5mL,盐体积分数为46%,缔合时间17min,气浮流速20mL.min-1,浮选率可达100%,富集倍数为10,优于单一的双水相萃取.Cd(Ⅱ)含量在0.050～5.000mg·L-1与吸光度呈线性关系,线性方程为F=2.8967C-0.1474,可决系数为0.9996,检出限为0.0113mg·L-1,相对标准偏差RSD为1.8%(n=15).该方法在痕量/超痕量分析的样品前处理中有较好的应用前景.

Combining solvent sublation with aqueous two-phase extraction （ATPE）, a new preconcentration/separation method was established： aqueous two-phase gas solvent sublation （ATGS）. Then ATGS was applied to preconcentrate/separate Cd（Ⅱ） in the environment prior to flame atomic absorption spectrometric determination. The effects of analytical parameters including pH, proper condition of phase separation, volume of complex reagent and flotation time on the recoveries of heavy metals were investigated. The recovery of Cd（Ⅱ） was 100%. Cadmium was concentrated 10 times using this method, which is much better than aqueous two-phase extraction alone. For concentrations of Cd（Ⅱ） from 0. 050 mg·L^-1 to 5. 000 mg·L^-1, the linear equation was F = 2. 8967C - 0. 1474 and the linear correlation coefficient （ R^2 ） was 0. 9996. The detection limit of Cd（Ⅱ） was 0.0113 mg·L^-1. Averaging 15 determinations of 1 mg·L^-1 Cd（Ⅱ） gave a relative standard deviation of 1.8%. The proposed method is shown to be promising for preconcentration/separation before the determination of trace and ultra-trace substances.