provoccrtive opinion "We Analytical Chemistry Teachers Don't Get No Respect" Maybe We Would if We Really Taught Analytical Chemistry Roland F. Hirschl Seton Hall University, South Orange, NJ 07079 The first course in analytical chemistry, often called the "quant" course, is the only course in analytical chemistry most students ever see. I maintain that the material taught " in this course has little connection with analytical chemistry. It has no relations hi^ to the vast maioritv . . of analvtical nrocedures used in the chemical industry, in clinical ;hemistry, or in environmental chemistrv, three of the manv areas in which the impact of analyticLl chemistry is en&nous. It does not explain the role of analytical chemistry in thr real world. It does not provide the student even a peek at the exciting and diverje topics of research in analytical chemisrrv thnt we at the cdlcges and universities and our colleagues i n industrial and government labs are pursuing. The bulk of'thequant course, and of the textbuoks used in teaching it2,is devoted to aqueous chemical equilibrium and vdun~etricanalvsis. The tvnical text devotes 40-605 ilf its pages to this uf top,&. Almost invariably this is the f~rst40-6IJoi of the h o k . Since we rnrelv haveenourh time to cwer the entire textbook, this means that our ruurses prohably have an even higher fractiun of rhe lecture time devored to~thesetopics. Now, how much of this relates to analytical chemistry? In fact, the practice of analytical chemistry today almost never involves a titration or an aqueous solution a t equilibrium. Elemental analyses are carried out in the gan phase, generally in a plasma or flame. Clinical analyses are routinely done bv a continuous-flow techniaue. Freauentlv the chemical reactions in such systems are far from equilibrium a t the time the measurement is comnleted. Most other analvses of organic and biological mixtures are done by chromatographic, electrochemical, or spectroscopic techniques or some combination thereof. Most of these techniques likewise do not depend on an aqueous chemical equilibrium heing reached. At best, a steady state exists through which the species of interest pass quickly, making the measurement dependent on the rates of the chemical reactions in the system at least as much as on the positions of the equilibria. The majority of
Based in part on remarks at the Joint Great Lakes and Central Regional ACS Meeting. Kaiamazoo. MI, May 24. 1984, and at the Middle Atlantic Regional Academic Analytical Chemists Conference, South Orange. NJ, November 7, 1986. On Leave at Division of Chemical Sciences. U.S.Department of Energy, Washington. DC 20545. No specifictexts will be referenced as the problem appears to be general.
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the systems do not involve a condensed phase. In those that do, the liquid as often asnot is nonaqueous (as in the stationarv most commonlv used in chromatoaranhv). -nhases . - . . By concentrating on aqueous equilibria and titrations in our basic analvtical chemistrv course we are imoring the chemistry that goes on in thk most used anaGica1 techniques. Our students are ill-prepared to understand the chemistry involved in the spectrometers, chromatographs, and automated analyzers they will be using after graduation. They surely gain no inkling of the concepts and approaches being tried in today's analytical research labs. We should instead be emphasizing the principles of flame and plasma chemistry, the fundamental concepts that explain the chemical processes that occur in the various types of mass spectrometric sources, the basics of the mass transport processes that are a t the heart of electrochemistrv and separations. Note that u,hat I am suggesting is quite difterrnt from the ~rilcticeat some colleges of de-em~hasizinathe"uuant" and ;eplacing it with i n s h m e n t a l analysis topics. w e need to avoid just teaching how an instrument works; our students should understand something of the chemistry that underlies the technique around which the instrument is designed, and, hence, the strengths and weaknesses of the technique. A second shortcoming of the quant course is that too much time is spent dealing with simple samples. Our students must get the impression that sampling and sample treatment is a trivial part of the overall analytical process since they hear very little about this in the lectures and do even less themselves in the labs. The difficulties of dealing with samples that are heterogeneous or unstable, or-as is most commonly the case-both, are ignored or handled in a separate lecture based on a brief separate chapter of the text. Present-day analytical chemistry is, however, routinely concerned with just these aspects. Instrumentation is generally extremely good at qualitative and quantitative determination of a component of a homogeneous sample a t the moment it is introduced into themeasurement device. But what the result tells us about the composition of the original material from which the analytical sample came is often highly uncertain. We need to find ways of incorporating lessons about sampling into every lab exercise and into each lecture topic in our basic analytical course. A third and related difficulty with the typical quant course and text is that the samples used as examples are unrepresentative. They are largely drawn from the same suite of samples that was established decades ago: aqueous solutions, mixtures of inorganic solids, alloys, and ores. Only infrequently do we give our students experience with hiolog-
ical materials, real environmental samples, or heterogeneous mixtures. Very rarely do they work with anything simulating an industrial process stream, yet the majority of present day analytical measurements are in fact made on line. By the end of the quant course our students should recognize that our measurements can only be reliable when the sample is the right sample, and the question being answered by the analytical procedure is the right question; that is, the performance characteristics of the selected combination of techniques are appropriate for the given problem (application). The close interconnection between the measurements and their interpretation is not adequately developed in our analytical courses.3 We have much still to learn and much to educate our students ahout these aspects of the analytical chemical task. Let me now state two of the conseauences to the ~ r o f e s sion of our misguided approach to teaEhing the hasiccourse in analvtical chemistrv. First. we ~ r o v i d ea verv poor introduction to real-world analytical chemistry. he students, most of whom will enter other subfields of chemistry or professions such as medicine, are ill-prepared to use-the techniques of analytical chemistry. Those who might consider analytical chemistry as a career do not sense t h e excitement which exists in the practice of our profession. Second, we raise doubts in the minds of chemists in the other academic subdisciplines about the value and the vitalitv of analvtical chemistrv. The teachine" of inoreanic chemis" try, organic chemistry, physical chemistry, and biochemistry has changed greatly over the last 30 years, reflecting corresponding changes in these areas, while our field appears to have stood still. In consequence, many influential chemists see analytical chemistry as a mature field. "Just let us buy the chromatographs, the NMR and mass spectrometers, the FTIR's, etc.," they say, "and we can handle all of our analytical problems." Indeed our instruments are powerful. We can often identify and quantitate substances in simple solutions with great recision and impressive detection limits. Given enoueh talented people, time, and money we can measure just about any substance a t almost any concentration level. This capa-
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This point is developed in Pardue, H. L.: Woo. J. J. Chem. Educ. 1984, 61, 409.
hility does not come close, however, to meeting the demands that today are placed on analytical chemistry. The materials about which people want information often are solids that are altered upon dissolution and usually are materials that are not homogeneous. Techniques for determining the distribution of composition (particularly with regard to oxidation states and species present) in three dimensions are the object of much research a t the leading edge of analytical chemistry. Further, many of the questions posed for analytical chemists require answers that must take into account changes in composition with time. Determination of the ecological fate of a potentially hazardous substance involves measurement of concentration levels and elucidation of pathways and rates of chemical transformations in the actual environment. Identification of the cause of a disease may require knowledge of exposure of an individual months or years before the present. These challenges to the analytical chemist are not coming from other chemists. Rather, they are the result of needs for chemical information felt h s persons outside the field of chemistry. Process engineers, medical practitioners and researchers, lawyers, molecular biologists, and materiala scienproblems and excittists are providing the difficult ing research ideas for analytical chemists (which is really rather similar to the situationin the other chemical suhdisciplines). We must change the content of our basic course in analytical chemistry to reflect the current state of the field. The principles we teach should he those that underlie our science. The attitudes we communicate to our students should be the attitudes of the real analytical chemists of today and not of 40 years of quant courses. General References Bard, A. J. "Analytical Chemistry", CHEMTECH 1985.15,337. Coleman, W. F.: Oma, M. V. "Teaching Analytical Chemistry", a report on seasion8 at tha EighthBiennialConfereneeon ChemicalEducation,Stoms. CT,Auguat 5-10.1984: J. Chem Educ. 1985.62,18. Elving, P. J. "The AnalytiealProeeaa in Chemistry", And. Cham. 1950.22.9B2. Hirsch, R. F.'"SomeIdeas on Analytical Chemidry Courses for Chcmlstry Mejara",Anol. Cham. 1970.42 (14). 42A. Hirsehfeld, T."Limita of Anslyds".Anol. Chem. 1976,48,16A. Laitinen. H. A. "Teaching of Anslytieel Chemistry-The Problem in Pcrspedive", A n d Chem. 1970.42 (14). 37A. Pardue, H. L.;Wm. J. "Unifying Approach to AnalVtical Chemi8trysad Chemical Ansly.is", J. Chem. Educ 1984.81.469 Rogsn, L. B. "The Inexact Science of Trace Analysis': J. Chem. Educ. 1986,6J, 3. Siggia,S."ReaehingStudenurwith AnslytieslChemiritry",Anoi.Chem.1970.42(111,49A. Warner. M. D.."Educatian in Madern Andytiesl Chemistry", Anoi. Chem 1985.57.278A.
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Number 5
May 1987
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