Speciation and Determination of Low Concentration of Iron in Beer Samples by Cloud Point Extraction
Speciation and Determination of Low Concentration of Iron in Beer Samples by Cloud Point Extraction
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DOI：
10.1021/acs.jchemed.7b00544
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发表时间：
2018-03-01
影响因子：
3
通讯作者：
Wright, John
中科院分区：
文献类型：
--
作者：
Khalafi, Lida;Doolittle, Pamela;Wright, John
本文描述了一个实验室实验，在该实验中，学生使用浊点萃取和吸光光度法测定啤酒样品中铁的浓度和形态。测定的基础是在胶束水溶液中铁与作为比色试剂的2 -（5 - 溴 - 2 - 吡啶偶氮）- 5 - 二乙氨基苯酚（5 - Br - PADAP）之间的络合反应，然后进行浊点萃取预富集。在添加和不添加抗坏血酸作为还原剂的情况下，分别测定了总铁和亚铁（Fe(II)）。使用浊点萃取测定实际啤酒样品中的铁浓度为学生提供了一个熟悉预富集、络合化学、掩蔽剂以及分析物形态的机会。学生还获得了从科学文献中调整方法、使用吸光光度法以及探索质量控制技术（如方法检测限和加标回收率）的实践经验。
A laboratory experiment is described in which students determine the concentration and speciation of iron in beer samples using cloud point extraction and absorbance spectroscopy. The basis of determination is the complexation between iron and 2-(5-bromo-2- pyridylazo)-5-diethylaminophenol (5-Br-PADAP) as a colorimetric reagent in an aqueous micellar solution followed by cloud point extraction for preconcentration. Total iron and Fe(II) were determined with and without addition of ascorbic acid as a reducing agent, respectively. The determination of iron concentration in real beer samples using cloud point extraction provides an opportunity for students to become familiar with preconcentration, complexation chemistry, masking agents, and the speciation of an analyte. Students also gain hands-on experience with adapting methods from scientific literature, using absorbance spectroscopy, and exploring quality control techniques, such as method detection limits and spike recovery.