Focusing a Comprehensive Lab Exercise in Trace Analysis

This paper describes the application of experimental instruction based on the project-oriented work concept, focusing on trace copper determination in cow milks by electrothermal atomic absorption spectrometry as a representative case of trace analysis. The project is suitable for senior students in analytical chemistry/instrumental analysis and is intended to cover relevant issues in trace anlisis: sample pre-treatment (drying, grinding, sieving, mineralization), method development (optimization of thermal programs), calibration, validation, and application to real samples. Experimental work involved in each of those steps serves the purpose of showing error risks inherent in trace analysis, sample dissolution, calibration methods, and validation, and also introduces other important concepts, such as recovery, calibration, procedural blank, and spectral and nonspectral interferences.