Sampling and Sample Homogeneity as Introductory Topics in Analytical Chemistry Undergraduate Courses

This work deals with the development of an experiment to evaluate the effect of sample characteristics on precision and accuracy of the sampling step. Parameters such as sample homogeneity, particle sizes, and sample mass were evaluated by analyzing the standard deviations (n = 3) obtained for Ca, Fe, Mg, Na, P, S, and Zn determinations in a breakfast cereal sample by inductively coupled plasma optical emission spectrometry. The proposed experiment can improve the assimilation of important concepts such as sampling, sample representativity, precision and accuracy by undergraduate students in analytical chemistry laboratory courses.