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研究了乙醇-硫酸铵双水相体系对Cr(Ⅵ)的选择性萃取分离效率及其原子吸收光谱法(AAS)分析。配制乙醇-硫酸铵双水相体系,并考察不同种类盐,盐用量,酸度和时间对体系萃取分离效率的影响,用AAS法测定体系对以重铬酸根形式存在的Cr(Ⅵ)的选择性萃取分离效率,通过乙醇和水相的AAS法测定选择了最佳萃取分离条件,在pH为4的酸性介质中把水相中的Cr(Ⅵ)萃取到乙醇相而Cr(Ⅲ)留在水相中,使两种形态的铬彼此分离,通过对醇相Cr(Ⅵ)和水相Cr(Ⅲ)的AAS测定,得到最佳测定条件及体系对Cr(Ⅵ)的萃取率为:双水相体系的体积为10.0mL,V(EtOH)∶V(H2O)=2∶3,(NH4)2SO4的质量为1.7g,pH4,Cr(Ⅵ)萃取率为90%以上,Cr(Ⅲ)回收率为98%～108%。本法可用于铬的形态分析。
The selective extraction and separation efficiency of Cr (Ⅵ) by ethanol-ammonium sulfate aqueous two-phase system and its analysis by AAS were studied. The aqueous two-phase system of ethanol-ammonium sulfate was prepared, and the effect of different kinds of salt, salt dosage, acidity and time on the extraction efficiency of the system was investigated. The AAS method was used to determine the selectivity of Cr (Ⅵ) Extraction and separation efficiency, the optimum extraction and separation conditions were determined by AAS method in ethanol and aqueous phase. Cr (Ⅵ) in the aqueous phase was extracted into ethanol phase and Cr (Ⅲ) was left in water Phase, so that the two forms of chromium separated from each other by the alcoholic phase Cr (Ⅵ) and aqueous phase AAS determination of Cr (Ⅲ), the best determination conditions and the system of Cr (Ⅵ) extraction rate: The volume of the system was 10.0mL, the mass of V (EtOH): V (H2O) = 2: 3, (NH4) 2SO4 was 1.7g, the extraction rate of Cr (¢ ö) was above 90% The rate is 98% ~ 108%. This method can be used for the morphological analysis of chromium.