OPEN PROBLEM SOLUTION IN ANALYTICAL CHEMISTRY: PROBLEM BASED LEARNING (PBL)
The problem based learning (PBL) is a methodology of teaching-learning that has been becoming important in the college education. Traditionally the process of solving problem starts with the explanation of the information to finish solving a supposed problem that has only one feasible result. In the case of the PBL the context of the problem is exposed firstly, and, after the identification of the requirements of the learning process, the information is found and the analysis and the resolution of the problem are made .
The learning process using open problem has been becoming important in the area of the Analytical Chemistry in the most of the universities of USA [2-6]. The PBL, understanding as orientated investigation, has six steps: i) realization of the qualitative analysis, ii) emission of the supposition, iii) elaboration of the strategies, iv) resolution, v) analysis of the results and vi) formulation of the news perspective.
In the present work the learning using open problems has been tested in three subject of the grade of Chemistry in the University of the Basque Country.
In the first subject, “Introduction to the Instrumental Analysis”, the proposed problem is connected with the validation of an analytical method. The analytical problem is the determination of the volatile compounds that cause the bad smell of the cow slurries using purge and trap preconcentration technique (P&T) coupling to the gas chromatography with flame ionization detector (GC-FID). The students have to propose the calibration methodology to obtain good results in accuracy and precision.
In the second, “Chromatographic Techniques”, the open problem is about one of the laboratory practice that the students make in this subject. The task of the open problem is that the students prepare the laboratory guide before their entrance in the laboratory developing an analytical procedure to the determination of several drugs in urine. Firstly, it is necessary to select the preconcentration technique after a theoretical study. Finally the technique is chosen taking in account this preconcentration technique.
The third example is carried out in the subject called “Experimentation in Analytical Chemistry”. In this case the whole problem is based on the analysis of drinking water. There are at least three open lessons where the lecturers explain: the drinking water supply, the legislation on drinking water and an overview of the analytical techniques. After a short report prepared by the students about those topics, a sampling scheme, sample treatment and analysis method and the discussion about the results are proposed by the students.
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