N235萃取火焰原子吸收测定水中微量Cr(Ⅵ)

Determination of trace Cr(Ⅵ) in water by flame atomic absorption spectrometry with N235 extraction.

用N235-甲苯体系,经过两次萃取,对水中的微量六价铬进行了分离富集,并用火焰原子吸收光谱法进行了测定.实验中Cr( )富集倍率为10,特征质量浓度为0.13mg/L,检测限为0.081mg/L.方法简单易行,重现性好.

Trace Cr(Ⅵ) in water was separated and enriched with two-step extraction and determined by flame atomic absorption spectrometry. The Cr(Ⅵ) was extracted in 0.2 mol/L hydrochloric acid with N235-toluene and back-extracted into a 0.2 mol/L sodium hydroxide solution. The preconcentration factor is 10. The extraction conditions such as pH, the concentration of N235 and NaOH were optimized. The effect of coexistent elements on Cr(Ⅵ) extraction and determination were studied. The characteristic concentration and the detection limit are 0.13 mg/L and 0.081 mg/L, respectively. This method is easy to operate and the reproducibility is good.