Ebrahimzadeh Homeira, Yamini Yadollah, Kamarei Fahimeh, Shariati Shahab
Department of Chemistry, Shahid Beheshti University, Evin, Tehran, Iran.
Anal Chim Acta. 2007 Jun 26;594(1):93-100. doi: 10.1016/j.aca.2007.05.013. Epub 2007 May 17.
Homogeneous liquid-liquid extraction method was studied based on a phase separation phenomenon in a ternary solvent system. According to this procedure, mononitrotoloenes were extracted by single-phase extraction in a water/methanol/chloroform, homogeneous ternary solvent system. Methanol and chloroform were used as consolute and extraction solvents, respectively. The homogeneous solution was broken by the addition of salt and a cloudy solution was formed. After centrifugation, the fine droplets of the extraction solvent were sedimented in the bottom of the conical test tube. Analysis of the extracts was carried out by gas chromatography. The optimization procedure was performed using Box-Behnken design. The variables involved were: sample and extraction solvent volumes, consolute solvent volume and phase separator reagent concentration. Optimum results were obtained under the following conditions: sample volume of 5 mL, extraction solvent volume of 55 microL, consolute solvent volume of 1 mL and phase separator reagent concentration; 5% (w/v). Under these conditions, the enrichment factors of 354, 311 and 300, dynamic linear ranges of 0.5-500, 1-500 and 1-500 microg L(-1), and limit of detections (LODs) of 0.09, 0.09 and 0.1 microg L(-1) were obtained for o-nitrotoluene, m-nitrotoluene and p-nitrotoluene, respectively. Finally, the method was successfully applied to the extraction and determination of MNTs in the waste water samples in the range of micrograms per liter with R.S.Ds.<13.2%.
基于三元溶剂体系中的相分离现象，研究了均相液-液萃取法。按照该程序，在水/甲醇/氯仿均相三元溶剂体系中通过单相萃取法萃取一硝基甲苯。甲醇和氯仿分别用作共溶剂和萃取溶剂。通过加入盐使均相溶液破乳，形成浑浊溶液。离心后，萃取溶剂的细小液滴沉淀在锥形试管底部。通过气相色谱法对萃取物进行分析。使用Box-Behnken设计进行优化程序。涉及的变量有：样品和萃取溶剂体积、共溶剂体积和相分离试剂浓度。在以下条件下获得了最佳结果：样品体积5 mL、萃取溶剂体积55 μL、共溶剂体积1 mL以及相分离试剂浓度5%（w/v）。在此条件下，邻硝基甲苯、间硝基甲苯和对硝基甲苯的富集因子分别为354、311和300，动态线性范围分别为0.5 - 500、1 - 500和1 - 500 μg L⁻¹，检测限（LOD）分别为0.09、0.09和0.1 μg L⁻¹。最后，该方法成功应用于废水中微克每升范围内一硝基甲苯的萃取和测定，相对标准偏差（R.S.Ds）<13.2%。
