topics in chemical instrumentation strumental methods in our chemistry curriculum. We have decided to reorganize our course and to expand it slightly from a three-credit 1ectureAaboratory course to two individual lecture and laboratory courses, each representing two credits. The lecture course will be a prerequisite for the laboratory. We also plan to improve coordination among our other advanced offerings, to assure that our of instmental are exposed to a wide methods, whether in the instrumental analysis course or in one of our other advanced laboratories.
committee, Professors Joyce Corey and James Cbickos, for their participation in the curriculum evaluation described here. This analysis was presented in part a t the Central1Great Lakes meeting of the American Chemical Society, Indianapolis, Indiana, May 29-30, 1991. Literature Cited 1.RaWiff~.A.;Mottola. H.A. J. Cham. Educ. 1991,68,643. 2. Sherren, A. T.J Chpm Educ. 1881,68,598;Bidl~lnsmyer,B. A ; S~hmitz,S.J Chpm. ~du= 1991.66, ~195:~ i r e hR. , F J c h m . ~ d u c 1987.64.438. . 3. c h ~ ~ i r n ~ ~ ~ d ~ Nn ~g Wi 1990,69 S~ ~ e ~ ( i~np rgi30). l 29. 4. Bra"", T.;Sch"bert,A.ne"d~A".i. Chem 1991.10,l.
Acknowledgment The authors express their appreciation to the other two members of our department's analytical chemistry review
Part II. The Choice and Use of Instrumentation Bradley T. Jones Wake Forest University, WinstonSalem, NC 27109 The proper choice and use of instrumentation in the universitv curriculum is an im~ortautfactor in the education of st;deuts in chemistry because analytical instrumentation has become invaluable to today's chemist ( I ) . To evaluate the current state of equipment in instrumental analysis laboratories around t h e country, a survey was conducted on the status of spectroscopic equipment, a type of instrumentation widely used in such laboratories. A questionnaire was mailed to 200 randomly selected colleges and universities having graduate programs in chemistry. As of the date of submission of this text, 95 responses had been received. Courses in Instrumental Analysis are offered by 93% of the schools responding. The average enrollment for the course is 24 students per year. The table lists t h e spectrochemical analysis techniques most commonly offered in the laboratory, the percentage of schools offering that technique currently and in 1983, and the average age of the commercial instruments currently employed. Perhaps the most enlightening information obtained from the questionnaire comes from the written responses from the participants. Each laboratory director was asked to describe the most difficult challenge to be faced in the immediate future. The resulting list of problems is described below. Problem 1: Acquisition of Modern Equipment (Cited by 79% of those responding). In recent years instrumentation costs have increased, while funding to support the acquisition of new equipment has become more scarce. Because each piece of equipment is designed for only one type of measurement, many types of specialized experiments may never be available to the student because the purchase of an expensive commercial instrument could not be justified. An excellent illustration of this problem is given in the following quote from one of the questionnaire respondents. It is becoming increasingly difficult to present experimental exercises to undermaduates on modern eaui~mentbecause of the high rwt and rapid drvrlopmrnt ofinrtrumentatiun. Weno longcr attempt to pprform walysea in our inatrumrntal lahc-
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Journal of Chemical Education
ratory relevant to the needs of current research laboratories. Neither techniques that employ the most expensive commercial instruments (e.g., Raman spectrometry, atomic fluorescence spectrometry, and atomic emission spectrometry) nor new techniques are often employed in undergraduate laboratories due to the cost restrictions mentioned above. Furthermore, many currently available instruments are woefully out of date (see table). Those instruments typically the most up-to-date are the WNisible absorption spectrometer and the infrared absorption spectrometer, with average instrument ages of 7.2 and 9.1 years, respective13 It is interesting to note that these two Spectrochemical Analysis Techniques Most Commonly Offered Technique
Atomic Absorption Atomic Emission Atomic Fluorescence UVIVisible Absorption Molecular Fluorescence Molecular Phosphorescence Raman Scattering Infrared Absorption
% Schools
% Schools
Using Technique (1991)
Using Technique (1983)'
93
78
10.5
43
44
12.7
3
-
10.3
97
78
7.2
73
36
11.4
6
-
9.4
9
3
9.5
84
62
9.1
1983data taken from Pickral ( I ) .
Average Age of Instrument (years)
are also the most commonly used instruments in researchoriented courses (1). Given this lack of new instrumentation, the laboratory director is faced with upgrading existing systems in order to offer "semi-modern" experiments to the analytical chemistry student. If the manufacturer discontinues the production of a particular instrument for any reason, parts and service for it become difficult to obtain. The following quotes from three questionnaire respondents help to explain the modernization problem. Our most difficult challenge is designing experiments that are up-to-date (vis-a-visthe real world), given our limitations in terms of equipment and expense. With advances that have been made in digital circuitry in particular during the past decade, there has been amajorrevolution in the types of instrumentation that have been put into use in industry, and academic laboratories need to keep pace. . . . The biggest challenge is modernization. The students especially need mare experience with wmputer-automated instrumentation. With advances in this area, we must be careful to insure that the students understand how these instruments work and that they are not thought of as simply 'black boxes'. Problem 2: The "Black Box" Effect (Cited directly by 12% of those responding). While acquiring new instruments and upgrading existing ones is of great importance to the laboratory director, this must be done with some caution. The design and construction of new analytical instruments have become more complex (2, 3). Signal processing and data manipulations have been revolutionized by the advent of microprocessor-based instrumentation. Manufacturers have begun to emphasize this aspect of their new equipment to the exclusion of any adequate description of the basic design (2). A serious limitation to t h e educational value of spectrochemical instrumentation lies in the design of the instruments themselves. Because the manufacturer usually expects that the instrument will be operated by a technician in a n industrial lab who may need to run hundreds of samples daily, the instrument is designed to simplify his task. The result is a "black box" arrangement. The solution to be analyzed is introduced into a sample chamber, some instrumental parameters are adjusted following a n outlined procedure, and the analytical signal is detected, amplified, processed, and displayed using the microprocessor control that is vital to the system. The actual measurement process is not readily observable from outside of the "box" and a s a result, the student is not able to follow the optical path of the instrument. "There is a real danger that students may become overly impressed, even mesmerized, with the glossy, computer-controlled capabilities of currently available high-tech instrument systems and may be unable to evaluate the total analytical process in t e r n s of its component parts" (4). I n addition to the respondent quoted above, several laboratory directors are concerned about this problem.
The high cost of new equipment, combined with the inability to have the students physically *see"how instruments operate (i.e., they are computerized %lack boxes" that can't be tinkered with, disassembled, or modified by student hands) are the greatest challenges in instrumental analysis. We are training technicians, not scientists. We want students to have contact with modem instruments that at least somewhat resemble what they will see in the real
world. On the other hand, we do not want the instrument reduced to simply a '%lack box" that makes the instrumental course a course in getting out results. We want the students to understand the instrument, and modern instruments are not conducive to being taken apart and examined. We need to emphasize fundamental concepts. We need to avoid the problem associated with highly computerized instruments that allow an unskilled student to push a few buttons and get results without understanding what is happening. We need to teach chemists, not train technicians. Problem 3: Instrument Upkeep and Maintenance (Cited by 22% of those responding). As analytical instrumentation becomes more complex, keeping each instrument in working order becomes a more difficult task, especially when the device is used only one or two days per week during the academic year. I believe we may be doing a disservice to the student when we use such outdated eauioment. More time is svent trouble .. shooting and repairing worn-out instruments than in teaching the concepts of instrumental analysis.
Expensive maintenance contracts can auicklv devour fun& for the much needed acquisition of new equipment. Even with such contracts, unexpected instrument down time may cause some students to miss completely a particular experiment, while leaving the frustrated laboratory directo; trying to improvise quickly a n alternate one Conclusions The Instrumental Analysis laboratory director is faced with some difficult decisions concerning the experiments offered to undergraduate students. One can attempt to secure funding for a new piece of equipment each year, thereby slowly upgrading the laboratory. This would surely be a formidable task, requiring large amounts of time for proposal preparation and funding for upkeep. A second option would involve the use of instrumentation available from individual research emups within the chemistry department. While this type o?inskumentation is normallv in better condition than dedicated "educational" equipment, reserving such equipment for one or two laboratorv periods per week over the course of a semester can become inconvenient to the research director to say the least. Even with good cooperation among the chemistry faculty, some instrumentation may not be available. Lastly, the laboratory director may choose to make the best use of the equipment available to him,regardless of its age. While these instruments may not represent the state of the a r t for a certain technique, the components of the svstem should be basicallv the same a s those of their new& counterparts. The most recent equipment often differs from previous models only in packaging, data processing capabilities, or automation. These advances have little to do with the theory behind the measurement process, and in fact they tend to obscure it a s stated above. The simplest system available may in fact be the best teaching tool, even though such educational equipment may appear to be outdated or archaic. Literature Cited 1. Pichal, G. M. J. Chem. Edue. 1985.60,.4338-A340. 2. Stmbel, H. A. J Chem. Educ 1984,61,A5SA56. 3. Stmbel, H.A. J Ckm. Educ 1984,6I,AS%A94. 4. Pleva, M. A.; Settle, F. A,, Jr J Cham. Educ 1983,62,ABk4SI.
Volume 69 Number 10 October 1992
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