可视移动中和反应界面离线富集-毛细管电泳法检测电镀废水中痕量重金属离子

建立了一种可视化的、利用移动中和界面离线富集-毛细管电泳检测电镀水中痕量重金属离子的新方法。在该富集系统中,阳极电解液为2.1 mmol/L HCl-98 mmol/L KCl-痕量重金属离子,阴极电解液为4.0 mmol/L NaOH-96 mmol/L KCl,界面向阴极移动,分离电压为180 V,阴极电解液和阳极电解液的流速均为1 mL/min。富集后凝胶中的金属离子浓度用毛细管电泳检测,标准曲线在实验浓度范围内均有良好的线性关系(r≥0.9985),预富集倍数达80～150倍,Cu(II)、Zn(II)、Ni(II)、Mg(II)、Ca(II)、Cr(III)和Fe(III)的检出限分别为0.163、0.256、0.077、0.153、0.203、0.062和0.142 mg/L,均明显低于国家规定标准;日内和日间精密度均小于7.42%。所建方法已成功用于实际电镀废水样品中痕量重金属离子的富集和检测。

Trace analysis of heavy metal ions in electroplate waste water by capillary electrophoresis with visual offline sample stacking via moving neutralization boundary

A moving neutralization boundary(MNB) was developed as a novel model of visual offline sample stacking for the trace analysis of heavy metal ions(HMIs) by capillary zone electrophoresis(CZE).In the stacking system,the motion direction of MNB to cathode was used with 2.1 mmol/L HCl-98 mmol/L KCl-trace metal ions in the anodic solution and 4.0 mmol/L NaOH-96 mmol/L KCl in the cathodic solution.The voltage was constant at 180 V and the flow rate of the anolyte and catholyte was 1 mL/min.The metal ions in the gel after stacking were detected by capillary electrophoresis.The calibration curves showed good linear relationship(r≥0.9985) in the concentration range used in the experiments.The pre-concentration factors were up to 80-150 and the limits of detection(LODs) were 0.163,0.256,0.077,0.153,0.203,0.062 and 0.142 mg/L for Cu(Ⅱ),Zn(Ⅱ),Ni(Ⅱ),Mg(Ⅱ),Ca(Ⅱ),Cr(Ⅲ) and Fe(Ⅲ),respectively,obviously lower than the national standards.The intra-day and inter-day assay precisions were good(the relative standard deviations(RSDs) less than 7.42%).Finally,the developed method has been successfully used for the stacking and the detection of heavy metal ions in electroplate waste water.