I'll describe an undergraduate project-based experiment where students develop a method to measure iron, and determine the speciation of iron in the ppb range, in beer samples.  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, absorbance spectroscopy, and exploring quality control techniques, such as method detection limits and spike recovery.

Determining the concentration and speciation of iron in beer samples using a cloud point extraction technique for sample preparation coupled with absorbance and emission spectroscopy

255th National Meeting (2018)

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