Micelle-Mediated Extraction of Heavy Metals from Environmental Samples: An Environmental Green Chemistry Laboratory Experiment

A new laboratory experiment in which students extract and analyze several metallic contaminants from environmental samples is presented. The experimental procedure employs extraction of the target analytes by using an environmentally-benign preconcentrating technique prior to the identifications, which are carried out with a flame atomic absorption spectrometer. The extraction procedure employs complexation of the metallic species via a chelating agent, entrapment and solubilization via micelle formation, and isolation via phase separation when the solution temperature is raised. The overall process involves preparation of standard solutions and construction of a calibration curve, analysis of water samples, and evaluation of the matrix effect, through the analysis of several spiked samples. As a part of the evaluation protocol, a reference sample is also analyzed. Students become familiar with basic principles of analytical, environmental, and green chemistry through a "real world" application.