Analytical chemistry at a community college: A balance of wet chemical methods and instrumental analysis

Abstract

Within the last decade there has been considerable interest within undergraduate chemistry departments in changing from the traditional course-associated laboratories to a separate and integrated lahoratory program, representing all areas of chemistry. The integrated laboratory cuts across the traditional boundaries of the classical subdivisions of chemistry to allow for experimentation which more closely reflects the interdisciplinary nature of current chemical research. Such a program could also eliminate the sometimes trite and selfcontained exneriments often found in the traditional course-associated laboratory, and students could build a more flexible laboratow exnerience bv choosing among advanced . .experiments in several areas.The role of analvtical chemistrv in a totallv integrated lahoratory is illustrated-by the weli-established proeram at the Massachusetts Institute of Technology. chemistry majors complete four semesters of the integrated laboratorv course which begins the first semester of the second year andconsists of five hours a week in the lahoratory. The following three semesters each require ten hours a week. Associated lectures for two hours a week with each lahoratory course cover discussions of general information and explantions of specific points on each experiment. Although a given group of experiments performed in a prescribed order by every student is required in each course, a variety of experiments is offered from which the student can choose several to comnlete the course.Durlng thr four semesters of lahoratory the students perform 3 w~de selection of both class~cal wet anslgirnl methods and modern instrumental methods. In the first semester, for examole. the following experiments are performed: the equivalent weight of an unknown carhoxylic acid is determined by acid-base titration with a visual indicator and its pK, determined by potentiometric titration; the amount of cholesterol in a crude solid is determined by derivatization and quantitative visible spectroscopy; the yields of various products produced during the acetylation of ferrocene under different conditions are analyzed by quantitative high pressure liquid chromatography; and the analysis of student-prepared tris(ethylenediamine)cobalt(III) chloride is made for both cobalt, by cation exchange and subsequent acid-base titration, and chloride. hv the Faians ~recipitation titration method.From the above listing it is apparent that there need be no lack of analytical methodology in an integrated lahoratory sequence. The question, then, concerns the exact nature of the way analytical chemistry is presented within such a framework. Mere use of a wide selection of analytical techniques is not trainine for a orosoective analvtical chemist nor does it -. . accurately represent what practicing analytical chemists do. Analvtical chemistrv is a orohlem solvine nrocess which has ". a definite pattern involving much more than simply pushing a series of buttons in the correct order and copying a number from a digital readout. Importa...