Abstract

A major goal of green chemistry is to avoid the use of toxic organic solvents. In particular, there are few green methods allowing extraction and quantification of chromium species in environmental samples. Here, we developed home-made, dual-gel electromembrane extraction combined with a microfluidic paper-based analytical device for the simultaneous determination of Cr(III) and Cr(VI) in water, without using any organic solvent. The positively charged Cr(III) and negatively charged Cr(VI) migrated selectively into the cathodic (pH 2.0) and anodic (pH 3.0) aqueous acceptor phases, respectively. After extraction, the anodic acceptor phase containing Cr(VI) was analyzed directly by a microfluidic paper-based analytical device, after the addition of the diphenylcarbazide colorimetric reagent. The cathodic acceptor phase containing Cr(III) was mixed with Ce(IV) to oxidize Cr(III) to Cr(VI), and then, Cr(VI) ions were detected on the microfluidic paper-based analytical device after adding diphenylcarbazide. Under the optimized conditions, limits of detection of 2.0 and 3.0 ng/mL and extraction recoveries of 58.8% and 83.3% were achieved for Cr(VI) and Cr(III), respectively.

中文翻译：

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双凝胶电膜萃取和微流控纸基装置测定水中的Cr（III）和Cr（VI）

摘要

绿色化学的主要目标是避免使用有毒的有机溶剂。特别是，很少有绿色方法可以提取和定量环境样品中的铬。在这里，我们开发了自制的双凝胶电膜萃取结合基于微流控纸的分析设​​备，可同时测定水中的Cr（III）和Cr（VI），而无需使用任何有机溶剂。带正电的Cr（III）和带负电的Cr（VI）分别有选择地迁移到阴极（pH 2.0）和阳极（pH 3.0）水受体相中。萃取后，在添加二苯卡巴肼比色试剂后，通过基于微流纸的分析设​​备直接分析包含Cr（VI）的阳极受体相。将含有Cr（III）的阴极受体相与Ce（IV）混合，将Cr（III）氧化为Cr（VI），然后在加入二苯卡巴肼后在微流纸基分析仪上检测到Cr（VI）离子。在最佳条件下，六价铬和六价铬的检出限分别为2.0和3.0 ng / mL，萃取回收率分别为58.8％和83.3％。