In traditional undergraduate laboratories, students seldom participate in the development of experimental procedures. They follow recipes without making connections, limiting the conceptual gains targeted in the experience. To tackle this problem, a guided inquiry laboratory for the determination of metals in honey was designed for the advanced level analytical chemistry. Guiding material provides 3 types of experimental scenarios (9 metals) that can be implemented after a short planning period. Students choose a metal and design a simple analytical method using an external calibration. This method is validated by comparing results from the external calibration to those obtained with the standard addition method, known to correct for most matrix effects. Difference between the two values implies that the simpler external method is not valid, and the lengthier standard addition method is necessary to obtain accurate analyte concentrations. Inquiry into different experimental possibilities allow students to engage in decision making, generate procedures and study the sample as a whole, experiencing more closely than in traditional laboratories, the real analytical process.
Bernal et al. (Mon,) studied this question.