A Course at the Master Level Demonstrating Quality Assurance by Spectrophotometric Determination of Iron in two experiments

In two experiments, the first a batch determination of iron, and the second determination of iron by flow injection analysis, the students perform a number of repetitions. The measurements were repeated until it became possible to estimate which one of the two methods exhibited the better performance with respect to figures of merits and with respect to uncertainties. Four lectures were given on basic concepts of quality assurance and two sessions were offered on using the instrumental method. The work was performed in groups of 3-4 students. A standard operating procedure and an uncertainty budget was constructed by the students for the two methods and the performance was estimated by ordinary methods of statistical tests. It was explained to the students that the aim of the work was to determine the concentration of an unkown by two independent protocols. The investigations lead to a comparison of the methods and a best estimate of the concentration of the unknown that was withheld until the last minute before putting the finishing touches to the report. Thus, the competency of the student was monitored only by evaluating the data processing and the conclusions obtained by the results and by the validation of results, and not by the proximity of the result to the expected value. The work provided a set of results that were unbiased and independent, which may be applied to proposing definitions of precision and accuracy of instrumental analysis in general. The competency of the students was evaluated by a written report and the total workload corresponds to 2.5 ECTS points.