Scientific Instrumentation in Chemistry, Biology, and Physics An Interdisciplinary Approach Robert A. Izydore, Charles R. Jones, Mary M. Townes, a n d Harriet Ammann North Carolina Central University, Durham. NC 27707 A good background in instrumental methods is necessary to science majors both a t four-year and a t two-year colleges ( I ) . In the scientific job market, employers generally look for such a background no matter what type of position is to be filled (2) and admissions committees a t graduate and professional schools highly recommend a strong exposure to instrumentation for admittance to their programs (3).As the number of instrumental methods increases, and as the cost of continues to escalate. it becomes in.-instrumentation ~-~~ creasingly difficult for teaching institutions to purchase and maintain adequate instrumentation for their undergraduate courses. At most institutions, each science department deals with this problem separately. This often results in duplication of or overlapping of courses which aim to develop similar skills. This oroblem is more serious a t smaller institutions where limited budgets and small class enrollments make the duplication of courses amone the various departments and the corresponding purchasi of duplicate instrumentation imoractical and inefficient ( 4 ) . An auuroach to this problem which has met with some success in&~lvesthe use of a cooperative mobile instrumentation laboratory which circulates among neighboring schools (51. The initial purchase price of the instruments and van, as well as the costs of their yearly upkeep, are equally shared by each of the cooperating schools. Thus, the average cost per year for each school becomes affordable. , thestudents a t each school have the ooportunity to use a wide variety of instruments, many of which would not he available without the cooperative effort. The major drawbacks to this approach are 1)that the mobilelahoratorv can he oresent a t each school onlv one or two times ner \Par and ?)that wch schod must alrcr its rurriculum tu most ~ i f e c t ~ wul vl i l ~ zthe ~ m(hil~ lal~oriltorvwhen it i i availiihlt.. A different strategy is presented here, one that we have been usinr on our camuus for the vast four years. came to realize that many important instrumental techniques are common to a number of scientific disciolines. We identified those techniques that were common t o the disciplines of chemistry, biology, and physics and proceeded to develop an interdisciplinary course in scientific instrumentation. Realizing certain instrumental methods are of more utility to one discipline than the other, we attempted to retain some degree of specialization. The course offers certain advantages. From an economic standpoint, it eliminates duplication of equipment. The interdisciplinary aspect of the course broadens the student's scientific background and gives a greater appreciation of the overlap of the various scientific disciplines. Moreover, it promotes interaction between both students and faculty of the various disciplines. ~~
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Course Description The course was desiened to be taken bv iunior-level students from each of the ihree departments. Kwever, it is also onen to beeinnine M S . graduate students who have deficiencies in their instrumentation backgrounds. Its purposes are 1) to give students majoring in chemistry, biology, and physics a general knowledge of the theory and application of instrumental methods that are widelv used in science., 2 .) to give practical experience in the operation of instruments and ~~
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the interpretation of the data gathered from these instruments, and 3) to show how these instrumental methods can he used to make measurements and solve problems in all three of the scientific areas. The course consists of two basic components, a "common" component and an "optional" component. The common component, whose topics are entirely interdisciplinary, must he completed by all students. The optional component offers the student a choice of studying instrumental methods more specifically related to the individual disciplines. Typically the students attend two 75-min lectures and two 2-hr lahorntorv sessions per week. However, there is some flexibility in this arrangement since some topics differ in the relative amounts of lecture time and laboratory time required. Table 1 lists the prerequisite courses that students majoring in each of the departments would have completed prior to enrolling in the scientific instrumentation course. It can he seen that two semesters of general chemistry are the only common prerequisities. One instructor from each of the three deuartments participates in teaching the course with each topic being assigned to the instructor that has the most exuerience in that ~
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either all three or a t least two of the three scientific areas. For instance, all modern instrumentation employs some electronic subsystem. Therefore, the topic of electronics is a fundamental element of the course and is presented as the first topic. U1traviolet-visible spectrophotometry is an important tool in many areas of physical and biological science. It can he used Table 1. Courses Completed by Students Enrolled In Scientific Instrumentallon cornme
Chemistry 1100 Chemistry 1200 or 1300 Chemistry 2020 Chemistry 3010, 3020 Chemistv 3100,3120 Biology 1300 Biology 2100 Biology 2400 Physics 21 10. 2120
Physics 2310. 2320 Physics 2410, 2420
Title
General Chemistry'."E General C h e m i ~ l r y ~ . " ~ Quantitative Analysis' Organic Chemilrya.a
Organic Chemistry a.a Introduction to Molecular Biologyb General Zoologyb General Botanyb General Physicsb General Physics wlcalculuse~' Physics Laboratoryc
'Taken by all chemistry majors. a Tahen by all biology majors. *Taken by all physics majors. *May bs taken concurrently with Scientific lnrfrurnenlation.
Table 2. Topics In the Common Component Electronic Transducers and Components Ultraviolet-Visible Spectrophotametry 31 OH Measurements 1)
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4) Gas Chromatography 5) Zone Electrophoresis
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by the physicist and chemist to detect and study electronic transitions and by chemists and biologists to determine the structures of molecules and for auantitative determinations. The concept of pH is important i; both biological and physical systems. Separation techniques are important in all branches of science. Moreover, they are considered most important to premedical students (3).They can be utilized in compound purifications, separation of colloidal particles from their dispersion medium, separation of radioactive isotopes, and the separation of a large variety of other types of mixtures. Some of the important instrumental methods of separation are chromatography, electrophoresis, and high-speed centrifugation. Of these methods, gas chromatographic and electrophoresis separations were included in the common component. This is due to the relative importance and low cost of gas chromatography in effecting a wide variety of separations and to the importance of electrophoresis for the separation of biological systems. T h e topics included in the optional component are listed in Table 3. These topics are less general than those in the common component, and the costs of the instruments required are generally too high to procure a sufficient numher of them to service an entire class. Three of the topics are offered concurrentlv for a two-week oeriod. and the remainine three topics are taught concnrrenily f o r a second two-we& period. In each two-week period, one topic is offered in each of the three departments. Each student is free to choose the tonic that most interests him or her durine each two-week The two most popular topics thus far have been hieh-nerformance liouid chromatoma~hvand radiochemistrv. thire'fore, the schedhe is arranged so that they are taught k different two-week periods. Table 4 summarizes all of the topics covered in the course dong with the laboratory exercises and gods for each topic. We anticipate that some of the topics will change from year-to-year to reflect the interests of new faculty who are assigned to the course and as new instrumental techniques become-important. The choice of topics to he included in each of the two components was made after a consideration of a numher of factors. It was important that each topic be consistent with the general goals of the course. Each topic should be approved by all three departments. Instrumentation for teaching a topic must already he in place or be available for purchase either through grant funds or through departmental funds. More specialized topics to be included in the optional component could reflect the research interests of the faculty in the individual departments. Adequate time should he available to teach a topic a t a level agreeable to each department. Thus, a number of relevant tooics such as infrared and nuclear maenetic resonance spectroscopy were excluded because they c o i d not he taught in sufficient denth to he included in the course. Thev are. however, taught in othvr t ~ x l i t i n p( . ~ u r > rini t h e departrnent 0 1 chemistrs. Finallv. i t was t l ~ ~ l i r uto l ~rhwse l~ instrumental methods that could-be utilized either in other science courses or in research projects so that the instruments purchased could be used throughout the year and not only for the purDose of teachine the course. The t o ~ i c schosen were then customized to fit the circumstances a t our school. The basic format of our course can be adapted hv most schools, both a t two-year and a t four-year instftution;. The numher of participatina departments can vary as can the topics chosen to be presented: At the beginning of the course, a brief review of such ~~~~~~~
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Table 3. 1) 2) 3) 4) 5)
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subjects as measurement of errors, graphical analysis, and the least square principle of statistical error analysis is presented. Instructions for the operation of a Terak microcomputer are also given, and the students are asked to use the computer to analyze and treat some of their experimental data. No suitable textbook was available to cover the diversity of topics presented in the course. Thus, we prepared a manual to he used in the course which presents the following for each tnoic: 1) a brief summarv of the theoretical hackeround n;eded b y the students t o understand the instrumental method to be used; 2) a block diagram of the basic instrument; 3) sample calculations to illustrate the treatment of data; 4) detailed instructions on the use of the instrument: 5) the experimental procedure; and 6)instructions for preparing the laboratory report. At the end of the course, the students were asked to complete an evaluation form to give us their feedback. The vast majority felt that the course was beneficial in achieving their career objectives. Moreover, they indicated a preference to Table 4.
Toplcs, Laboratory Exerclses, and Goals ot the Scientific Instrumentation Course
Tooic 1) Electrical Transducers and Components'
2) Ultraviolet-Visible Spectrophotometrya
3) pH Measurementsa
4) Gas Chromatographyd
5) Zone Electrophoresis'
6 ) High Pertmmance Liquid Chromatography
7) High Speed Centrifugationb
8) Poiarimetrya
9) Laser Techniquesb
Toplcs In the Optional Component
High Performance Liquid Chromatography High Speed Centrifugation Poiarimetry Laser Techniques Radiochemistry Gamma-Ray Spectrometry
Journal of Chemical Education
11) Gamma-Ray Spectrometry
Assemble simple D.C.circuits from schematics. measure voltage and current: assemble and calibrate an electronic thermometer to illustrate the basic elements typically found in an instrument system: study A.C. circuits. learn to use an oscilloscope as a measuring tool; assemble an electrocardiograph to further study A.C. circuits. Measure ,A, and molar absorptivity of an organic compound in the UV region: determine the concentration of a p o t a ~ ~ i udichromate m solution in the visible region. Measure pH of common soMions: perlorm acid-base titrations determine buffer effects. Determine relative retention times of a homologous series of alcahais and determine the alcohols present in a mixture: perform a quantitative analysis of a mixture using peak areas and weight response factors. Separation of varieties of the hemoglobin molecule with a semi-micro electrophoresis chamber. Qualitative determination of the components present in a mixture of solid aromatic hydrocarbons; quantitative determination of a mixture of aromatic hydrocarbons using peak areas and relative response factors. Separation and identification of organelles after extraction from rat liver tissue. Measure optical rotations by studying the mutarotation of n-o-giucase and the inversion of sucrose. Measurement of molecular diffusion by light Scattering using a He-Ne laser: Studies of molecular spctroscopy using the apto-acoustic effect with a C 0 2 laser. MBBSU~B. by liquid scintillation counting. the rate of incorporationof radioactively labeled amino acids into proteins. Calibration techniques using standard gamma-ray sources: identificationof gamma-ray emitting nuclei by means of energy and half-life.
'Topic lnclvdsd in the Common Component a TOPCIncluded in the Optional Component.
take an interdisciplinary instrumentation course rather than one in their major, and they rated the opportunity to choose the topics of their interests as one of the strong points of the course. To date, our enrollments have averaged ten students per semester, hut we can accommodate 20 to 25 students per semester based on the number of instruments that are currently available. The course is offered as a five-semester-hour course with approximately 3%semester hours (11 weeks) comprising the common component and 11/2 semester hours (four weeks) comprising the optional component. Conclusion We feel that we have developed a scientific instrumentation course that fulfills all of our original goals. It has been well received by our students and faculty. The interdisciplinary aspect has helped promote a spirit of cooperation among the participating departments and has given each department a better understanding of the needs of the students majoring
in the other de~artments.As the course continues to develo~. and as more faculty memhers become involved in teaching it, these positive aspects will he enhanced. Acknowledgment We wish to thank the Southern Regional Education Board, administrators of the Kenan Trust Fund, and the National Science Foundation Instructional Scientific Improvement Propram for funds to purchase much of the equipment fur the scientific instrumentation course. We are also grateful to Professor Kinney H. Kim of our department of physics for his contributions in developing the gamma ray spectrometry topic. Literature Cited 111 Trujillo. A. P...I. CHEM. Enl!r..SO.ilY 110i:ll. (21 Svnllurd. H.S. and 0verend.l'. Rulic'..SJ.796 I1076l 1x1 Pirkml. I;. ('...I. C H K M R o I I c . . ~ ~IX" . Il!lifi).
J.,.I.?HEM.
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