Role-playing analytical chemistry laboratories. Part III: experiment

I

In the same way that a script defines the storyline and the motivation of the characters in a play, Part I (Anal. Chem. 1991, 63,977A) describes the reason for being and outlines the principles behind John P. Walters’ successful role- playing analytical chemistry classes. In Part I1 (Anal. Chem. 1991, 63, 1077A) Walters describes the setup of the lab space and equipment, thereby setting the stage and providing the props against which the play takes shape and the experiments are performed. Just as the actors rehearse before opening night, the students prepare before going into the lab. In Part I11 the lights go down and the curtain rises as the students go through their paces and the experiments unfold.

0003 - 2700/91/0363- 1179A/$02.50/0 0 1991 American Chemical Society

John P. Walters Department of Chemistry

St. Olaf College 1520 St. Olaf Avenue Northfield, MN 55057- 1098

The role-playing labs in the three courses mentioned in Figure 2 of Part I are structured to allow “freedom within a mission,’’ and all are based on the two educational principles of interdependence a m o n g skilled individuals and division of responsibility. The mission of each experiment is explicitly stated as one or more objectives, usually in narrative form. The interdependence among role-players is evident in that a time frame is suggested, and emphasis is placed on getting the work done with good coordination and interaction in even less time than allowed. Minimum responsibilities are suggested for each role-player, with the clear indication that Manager will define

each person’s responsibilities and evaluate how well things are going during the session. The distribution vehicle

The junior Analytical Chemistry course experiments are all in written form and are purchased as part of a lab manual at the start of the semester. During t h e semester, Upper Management distributes free updates as either hard or soft copy. The

written material is dynamically updated by exchange of comments between Managers, verbally or electronically, as the work progresses. In the interim course (Uses of Computers in the Health-Related Professions) the experiments also are written, although much more tutorial work occurs between a small staff of instructors and the students at indi-

ANALYTICAL CHEMISTRY, VOL. 63, NO. 24, DECEMBER 15,1991

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REPOR7 vidual computers. The essence of the work, especially in the liberal arts concepts, is also communicated by films and guest professional speakers. Because space limitations preclude a detailed discussion of these experiments in this article, suffice it to say that they are concerned with the basics of laboratory information management, medical image processing, and data telemetry. In the senior Instrumental Analysis course the experiments are dynamic and are-by intent, design, and definition-methods develop m e n t experiments. They a r e d e signed to produce a product, in addition to a specific result. That product may range from data to an actual write-up. The product will be used in, or as, an experiment in the junior course. This emphasis colors all of the experiments. Methods development experiments originate from problems encountered in t h e written experiments (e.g., elimination of a matrix effect in an atomic absorption spectrometry [AAS]experiment) or from the need to develop new approaches to use in the junior course (e.g., new robotics methods for potential inclusion in future junior course offerings). The written experiments also are purchased for t h e senior course. Those that cover basic instructions in instrumentation and computers usually operate over a three- to fouryear life cycle. Those that concern current methods development and problem solving usually are updated yearly to reflect what was done previously in the junior course or during recent summer research. The key distribution feature of the experiments for the senior course role-players is the weekly staff meeting with Upper Management, when much of the mission, division of responsibility, and specific interdependent work for the coming session are discussed with the whole class. This meeting reflects true cooperative educational decision making (11, because the teacher and the group caucus to decide about the work. Basic design criteria The design of all the experiments is based on adapting parts of the four functions of a professional analytical chemist, listed below, into the roleplaying construct. Chemical analysis. Production quality control, product evaluation, analysis of competitive substances, and environmental control demand a huge number of analyses of complex substances. These analyses have to be 1180 A

done with accuracy, sensitivity, and precision in a timely and cost-efficient manner. Technicians and professional chemists do this work, usually on call. The actual execution of analyses is the mainstay of the professional analytical chemist and cannot be ignored in academic courses. Methods development. All analysis methods are dynamic. Demands are made for methods with better sensitivity, accuracy, and precision that are performed in less time and for less money. Thus, by definition, all existing methods are obsolete as soon as they determine the composition of the substances tested, and every successful s e t of analyses spawns the need for a new method. Professional analytical chemists are continually in search of better, more productive methods that they either develop themselves or import from other contexts. Moreover, it is the unusual analytical chemist who can develop methods without actually doing analyses. This perspective also must be present in the modern analytical chemistry curriculum. Instrument development. Few analytical chemists today operate without being immersed in modest to heavy instrumentation. This is a direct result of the need for faster, more sensitive methods that can be used on complex samples of various and largely unknown matrix composition. Thus there is no way to be an analytical chemist and not be intimately involved with instruments, both from the hardware and software perspectives. Using the instruments usually involves more than just operation; design changes are in order, even for routine instruments, a s samples and matrices change. Many analytical chemists spend much of their time designing and building part or all of a n instrument, and some are better computer programmers and interfacers than their engineering counterparts. It is no longer adequate to relegate this educational aspect to other departments. Basic research. Not all of the physical and chemical principles that constitute an analytical method are so well understood that they can be taken a t face value for a melded set of experiments. Most analytical chemists know, from experience if from nothing else, that the way in which principles are blended may have a s much effect on the final method of analysis as do the actual principles. Principles, like chemicals, interact when they are blended, and often in surprising ways. A professional analytical chemist

ANALYTICAL CHEMISTRY, VOL. 63, NO. 24, DECEMBER 15, 1991

will always explore the principles on which the method is based, especially for properties or observations that will affect the interaction between seemingly independent systems. This is basic research in its primal sense, and a t the same time it is uniquely analytical. This flavor must appear “shot through” the entire analytical course offering and be quite obvious in each experiment. The management interview as an experiment component The professional design basis for the experiments is usually not evident to the student who is reading the material or attending a staff meeting for the first time. It becomes apparent, though, when Manager and Upper Management get together for t h e management interview (see Part I, “What about grading?”). It is expected that not only will data be interpreted, work critiqued, and a grade assigned, but also at least one “teaching moment” will occur when Upper Management can comment on how the experiment reflects what a professional analytical chemist does. The management interview is thus a key, unwritten, teaching function of t h e role-playing model, different from lectures or labs. The degree to which the role-playing experiments are time intensive has been questioned, considering the faculty-staffed meetings in the senior course, tutorials in the interim course, and management interviews in the junior and senior courses. If these aspects are eliminated and the role-playing construct is allowed to float throughout the class a s t h e mood of the moment suggests, then what remains is a solid core of conventional analytical wisdom, developed over the past 25 years of my active teaching career. The experiments were not developed to be carried out only in a role-playing mode; they will work in other environments and have been used with the written experiments by other faculty a t St. Olaf. Although time is a factor in the full role-playing model, it is a novel way to credibly extend the teaching component past formal lectures and labs and perceive it as something other than an onerous task needed to make the experiments work. The experiments do, however, have certain requirements for success in the role-playing model. For example, the problem-solving objectives, so central to the role-playing experiments, have to be creative, captivating, and yet manageable in one afternoon lab t o allow for interruptions

such as choir or football practice. They must have enough work to be a real organizational challenge if done by traditional individual effort, yet not so much that they require excessive work to master when performed in the role-playing mode. It is essential that the experiments reflect all role responsibilities in a natural way. For example, if a professional analytical chemist would never consider assembling his or her own connecting cable to link an instrument and a computer, then an experiment in which such a cable is needed must not require Hardware to fabricate one. They must also allow opportunities to make risky decisions and design mistakes (“shooting yourself in the foot”). They must allow Manager to make decisions that will produce local failures (a “bad afternoon”) as well as local successes, but not catastrophic failures (a “bad semester”). Finally, they must address the current state of the art in analytical work.

Experiment specifics The role - playing experiments devel oped thus far in the junior and senior courses begin by emphasizing chemical analysis and methods development as described above. Thus there are quality control experiments at the start of the junior course and methods development experiments at the start of the senior course. These experiments move from basic training (technique oriented) to problem solving (management dilemma). Both courses then conclude with research experiments. The box here and on p. 1182 A show the roles played in each course. They also state the objectives that Manager must implement and show how responsibilities can be divided. The role rotations that occur through the four positions at each company bench (see Figure 1, Part I) are crucial to the whole construct. Junior course basic experiments The first set of experiments in the junior course must teach a t least two things: how to role-play in a technical context (because most students have done this only in a social context) and how to handle division of responsibility for good laboratory practices. These a r e called roledefining experiments. Role-playing is best learned by associating accountability for t h e group’s success during the whole semester with how effectively each group member can teach others the

Manager Chemist Software Hardwar Manager Chemist Software Msrdwar

ivianager Chemist Software Hardwar

good lab practices inherent in his or her role. Unquestionably the most important laboratory practice that has to be taugh! is safety (2).This is a management function, and in the first experiment Manager learns how to teach the other company members

what laboratory safety means, what hazards exist in the lab, and how to interact safely with others. In a similar manner, Chemist begins by learning to teach the group how to read and understand a material safety data sheet (MSDS),han-


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dle nasty chemicals, arrange hood setups, and-especially importantdispose of potentially hazardous wastes. Software learns to teach 0thers how to use the executive terminal and the Xenix microcomputer so that 1182 A

they can dial out to the Mallinckrodt database (Lablink MSDS Data Base, Mallinckrodt Chemical Co., St. Louis, MO, available at 314-895-4870 and 1200 N 8 1) and capture and print a MSDS. (Chemist t h e n u s e s t h e


MSDS to instruct the others in the group.) Hardware learns to teach others how to use insulation displacement techniques, R J - 11 clamping, or even soldering to make a serial cable to connect the analytical balances and the pH meter to the serial port on the lab computer. Hardware also learns how to read the instruments’ factory manuals, how to calibrate the instruments, and how to teach others to do so. The skills are basic, but in combination with the responsibility for teaching others, role-playing is also learned and becomes a positive reinforcement for good interaction. In the second role - defining experi ment, the certification of volumetric glassware (3),the same people keep their initial roles but their account ability increases. For example, in addition to teaching, Manager has to decide which pieces of glassware to certify and how to schedule the certification in the time allowed for the experiment. Chemist has to learn how to properly and safely handle alcoholic KOH as a cleaning solution. Hardware has to learn how to manipulate the glassware (which does in fact require motor skills, as simple as it may seem), and Software has to develop a Lotus - 1 - 2 - 3 -like spread sheet to hold and analyze the data. (AsEasyAs is a Lotus - workalike spreadsheet available from Trius, Inc., 231 Sutton St., Suite 2D-3, P.O. Box 249, North Andover, MA 018451639.) To keep track of how things are going, all players have to interact with Manager and Software at the company computer, providing t h e first instance of group input into Manager’s decisions. The two-period pattern to these rotations continues through the first eight weeks of the junior course (see Figure 1 in Part I), and the experiments involved are structured with that time frame in mind. There are no “make-up” labs. Work unfinished in the allotted time is simply not finished. Manager has all the responsibility for organizational time management for the company. For the first four experiments, the players rotate roles every two weeks. The next experiment is always more challenging. Thus, students selected to be Managers in the first experiments feel the most stress of all the roleplayers because they are new to the experience. However, they also face the least demanding work to do in terms of time management because the succeeding experiments become more difficult. The next set of basic training, or

role -practicing, experiments for the junior course is designed to establish how differing degrees of mastery of basic laboratory techniques (e.g., motor skill based) may lead to various degrees of error propagation, which in turn may adversely affect overall method accuracy. I n these experiments statistical treatment of data is emphasized and the management role of round-robin method evaluation taught. Again, the primary management concept is accountability. For example, in the experiment Production Quality Control Lead Analysis, Manager faces the challenge of getting the company’s results into a common database fast enough so that all of the other companies’ data can be used to do roundrobin statistics. The actual objective of the experiment is to determine if there is a measurable difference between homogeneous and heteroge neous methods of precipitation of lead chromates, a s described by Ramette ( 4 ) . But to do this, each Manager needs results from the historical database and from all other work being done in the other companies that semester. Each company must function crisply to do this because there are no make-up labs and, for safety, no chemical work may be done in the lab room during offhours. In each experiment, Software handles the spreadsheets to do the sta-

tistical testing that Manager invariably calls for, and Chemist must provide Hardware with the neces sary reagents and compounds in time to complete the work. Much of the boredom and alienation of traditional analytical laboratory training disappears and is replaced with stimulating compromises and interactions. A detailed look a t one deceptively simple experiment is worthwhile to illustrate this point. The example is the Computer Simulated Weak Acid Titration, done as the third role- practicing experiment in the junior course. In a more conventional form this traditional experiment leaves little room for individual risk and/or stimulation. The focus is either on determining molecular weight, pKs, or acid identity, or on assay. In the role-playing form, the central objective is to do whatever work Manager decides is needed to determine if the solution’s ionic strength is in fact consequential in doing a titration. Manager must decide if the reason for doing the titration is to assay another compound or if it is just another academic hoop through which only the quick-witted may jump. In this context, the work may be similar to work done in the conventional experiment, but the different emphasis-and the division of responsibility i t suggests-can be very stimulating. Consider first t h e assembly of

Figure 1. Instrumentationto be arranged and cabled at the lab bench by Hardware and Manager in the Computer Simulated Weak Acid Titration experiment in the junior course.

parts for the experiment. One possible physical arrangement that Manager could ask Hardware to assemble is diagrammed in Figure 1. Although conventional, if the equipment is assembled this way, Manager must decide how to use it to generate the data and Hardware must arrange it on the bench and cable it to the computers accordingly. But first, Manager and Hardware must decide if Hardware will build a pH meter (see Part 11, Figures 8 and 9) or use the commercial instrument provided. This is not a trivial decision. Manager then has to judge the quality of the base standardization done by Chemist and instruct Software to either buy or build a spreadsheet to graph the titration while data are being collected. When the titration is under way, Manager decides how much data to collect to determine if the ionic strength is of consequence. As the experiment proceeds, Software enters the pH and weight readings into the spreadsheet, either one point after another or under some form of interactive program control, while Hardware and Chemist do the actual titration. If Hardware has constructed a pH meter, then Chemist has to prepare the solutions to calibrate it. Software will usually prepare the macro or the BASIC program needed to gather the pH readings into a serial port. The data,

Figure 2. Student data for the titration of a sample of citric acid as it would be displayed by Software near the end of the titration in the Computer Simulated Weak Acid Titration experiment in the junior course. The upper curve is the pH data, and the lower curve is the first volume derivative.


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REPORT however, must be graphed on the fly. Figure 2 shows part of an example graph near the end of a titration. This type of graph is rapidly redrawn as the titration progresses, often after each few additions of base. Thus Manager and Software can interact immediately with Chemist and Hardware while everyone is in the vicinity of the computer screen. (Figures 2-4 and 7 and 8 are graphed using t h e g r a p h function i n t h e AsEasyAs spreadsheet. Figures 5 and 6 are redrawn from original student data using Quattro Pro 2.0 to improve clarity.) While data a r e being acquired, Manager may decide if the data are correct and, for example, how much more base must be added. As the titration is sequentially portrayed it becomes clear that it is Chemist’s responsibility to get enough data so that Manager can make an intellig e n t decision a b o u t t h e ionic strength when Software finally executes the calculations on the data collected. Of interest is what happens in the second period when Software transfers the data to the central Xenix microcomputer and does the simulation. This simulation indicates what should have been observed in the experimental work, with and without activity corrections, so Manager instantly gets information about the ionic strength. Manager also gets insight into where data points should have been taken a t the highest density (it is not at the endpoint!) and usually calls the group together to repeat parts of the titration and data acquisition. Thus, although the setup and execution details of the experiment are “just those of a pH titration,” the responsibilities assumed by the people acting out the roles while doing the experiment, and Manager’s decisions about them, lead to some stimulating compromises and interactions. The whole lab can become quite lively in this and other experiments. A final role-practicing experiment in the junior course focuses on exploring potential consequences for a stable professional analytical lab when the dual-beam spectrophotometer is automated as a remotely operated instrument. The details of this approach were presented in Figure 5 in Part I1 for the mock robot experiment. Again, the main feature of the exercise is the high degree of interaction t h a t occurs between Software and Hardware in remote instrument operation and automation. Software works the company computer at one 1184 A

end of the bench while Hardware works the company spectrophotometer at the other end. Chemist works the middle of the bench, and Manager circulates. To add process control realism to the “remote” instrument operation, Hardware and Software can only communicate by intercom (not face to face), and Manager must arbitrate such problems as how much data to take, what solutions to prepare, when to store data on disk versus when simply to record it, and what to do with the data after storing. Manager’s chemical objective is simply to record a perfect isosbestic point for an acid-base indicator. Although the mechanics of d a t a gathering a r e eventually understood to be routine, the responsibilities assumed while gathering under these remote conditions require decision making on the fly. Most students conclude that automating a method requires more intellectual effort than doing it manually. Senior course basic experiments In the senior course, the role-emphasizing experiments not only have to include a specific technical function but also must teach how to develop a role emphasis for later when the students do their methods development work to make a product experiment for the junior course. Because most of the class has already done role-playing, the students either know or can quickly learn from others what that involves. The more subtle aspect here is how to establish the emphasis in a methods development project so that it focuses on or favors a particular role that needs maintenance or improvement. The technical function of these first experiments is development of those aspects of computer interfacing associated with data acquisition and instrument operation; almost without exception, senior chemistry students have little practical experience in such work. These two functions of role emphasis and computer interfacing, fortunately, blend together nicely. The first four experiments are executed individually in t h e senior course in the small lab room (see Part 11, Figure 21, and for each one it is clearly stated which role is dominant for successful completion of the experiment. Thus the concept of role emphasis in a product experiment for the junior course has a specific thing or action associated with it. It is not an abstraction. For instance, the experiment on


serial A/D conversion and data telemetry is managerially focused because it poses the question of how much data to acquire and how fast to adequately describe a process. The analog data acquisition experiment is software focused because it requires the conversion of 12 bits of binary data carried in two eight-bit bytes into a four-digit decimal number to put data of sufficient numerical precision into a computer database for quality analytical work. The digital data acquisition experiment is hardware focused because it requires physical cross-mapping of multiples of discrete four-bit BCD nibbles into weighted eight-bit bytes in the computer on which the final pH will be displayed. The experiment using digital data generation with D/A converters is chemically focused because it poses the question of how to drive the pump in gradient HPLC or to scan the potential in a voltammetric experiment through a BASIC program t h a t operates the D/A converter on the controlling computer. (The computers used are not the central issue. Early work was done with Commodore VIC-20 computers because of their economy and simplicity. Recently we have used Mac I1 computers that are memory mapped in a manner similar to the VICs. Other work h a s been done with Heath H-100 computers.) When these first experiments are assigned and discussed in the weekly staff meeting, the focus is on the technical skills developed as they relate to the emphasis of a particular role t h a t later will use computerbased instrumentation. In other words, the role metaphor is developed around the individual skills and specific apparatus needed to play a particular role in a product experiment that will eventually be used in the junior course. Interstitial experiments. These experiments are unique to the senior course. To establish the interdependence of roles in the senior course product experiments, and to make methods development clearly the primary focus, there are four interstitial (or role-practicing) experiments that follow the first four role-emphasizing ones. These experiments are designed to allow the four individuals in a lab session to build today’s work on the previous day’s efforts, using observations and developments made by those in the other lab sessions. The emphasis here is the value of information exchange-not only between roles, but also among groups. What

this can accomplish is an advanced awareness of how to design a n experiment so that interdependence can occur between role- players without diminution of the individuality of those who are interacting. The first interstitial experiment involves setting up the laboratory robot (see Part 11, Figure 10) to prepare a sample that will be used to measure the pseudo first-order rate constant of the hydrolysis of aspirin using UV spectrophotometry (5).As the experiment begins, there is little more than literature guidance for which pH to choose, which dilutions to make, when to make the UV measurements, which temperature to use, and how many samples to prepare (6). Hardware videotapes the results of one group, and the next group can base its approach on what the previous group has done. Again, this is practical in a role - playing context because it is Manager who sets the day’s goals and communicates to the next day’s Manager what was observed compared with what was expected. In two weeks of cumulative work, everyone in the class has seen eight to 10 videos, learned a great deal about how to make cumulative progress in a difficult task, and measured at least one rate constant that compares well with the accepted literature values. As pointed out in Part 11, the robot is an ideal vehicle for teaching this kind of group interaction. A previous experiment that

11

worked well with this same goal in mind (but has been discontinued because of time constraints) was building a DME polarograph, using A/D and D/A converters as well as custom-designed OA current followers and then developing a n analytical method. Perhaps one of the most intellectually interesting interstitial experiments will be attempted full scale for the first time this fall. LabView I1 (National Instruments Co., 6504 Bridge Point Parkway, Austin, TX 78730 - 5039) virtual instrumentation software will be used in a Mac I1 environment to cumulatively build a modest workstation for an HPLC detector. The actual LabView icons that form parts of the completed instrument can be exchanged between lab groups using the Appletalk network and a file transfer program such as Timbuktu. (Timbuktu, a Macintosh remote file-sharing program marketed by Farallon Computing, is available through Apple dealers or Macintosh mail order supply houses.) The network is pervasive on campus, and partial instruments can even be mailed and swapped between dorms on a daily basis if desired. I t is expected t h a t individual groups will assemble pieces of the workstation each afternoon, and eventually one group will get them all “wired” together to make a display that works. From then on, the system will be refined to make the product mimic, as closely as possible,

the commercial versions, while remaining usable in the junior course. This methods development experiment has been explored in the senior course over the past two years and has been refined during summer research.

Management dilemmas and problem solving experiments A series of experiments that occurs at the end of the semester in the junior and senior courses provides much excitement in the role - playing con struct. They have no exclusively right answers, and some creative blending of technology and ethics is needed to reach a result. They are called management dilemmas in the junior course and problem solving experiments in the senior course. These final experiments have been identified from graduate research and industrial consulting experience. They are research-like, yet manageable in the undergraduate environment. The eight that will be used this year, four in the junior course and four in the senior, are listed in the boxes on pp. 1181A and 1182 A. Experimental details will not be given here; instead, I will discuss the problem-solving objectives and the way in which the roles operate. In each experiment the objective is stated as a target goal, but the vehicles for achieving it-areleft largely to Manager. In the junior course they are called dilemmas because they all have explicit and significant ethical

-

iible Wib!e EFter-Egg Grass Scw

Figure 3. Student data from the spectra of three dye samples displayed for Manager in the Edible Easter Egg Grass Dilemma in the junior course. Key: A, yellow; +, red; X, blue.

Figure 4. Student data of a commercial spray urethane sample prepared on a cloth gauze and analyzed by Chemist in the Pattern Matching of Spray Lacquer Products by FT-IR Spectrophotometry experiment in the senior course.


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REPOR7 overtones, as well as the usual technical compromises that accompany practical research and industrial a n alytical tasks, making it difficult to arrive a t a clear-cut optimal solution. In the senior course, the technical aspects are developed according to what were defined in the previous year’s junior course as problem areas worthy of methods development effort. The senior course role-players must ensure that whatever developments are made, the problems will still present the junior course Managers with dilemmas that will constitute their biggest challenges. The experiments are described below, including the ethical dilemma and professional activity that each demonstrates. Edible Easter Egg Grass Dilemma. The purpose of this junior course experiment is to illustrate the problems encountered in advertising ethics. Students are asked to identify and compare, by product dissection, potentially competitive industrial dye products using food coloring (7). The challenge is to determine if one product is composed of the same combination of dyes as the competition’s product. Manager must make a series of decisions about how to do the spectrophotometry to analyze the products. Chemist prepares the proper concentrations of quickly needed standards. Hardware must operate the spectrophotometer. Software, in consultation with Manager, must determine how to analyze the data so that the desired information can be obtained and a decision can be made about whether to challenge the competition’s advertising claims. The experiment has produced some very interesting small-group dynamics and involves solid instrumental chemistry. Technical parts of the solution have ranged from conventional multicomponent to differential and derivative spectrophotometry. Other considerations of risk management and the ethics of competitive maneuvering have produced lively manage ment interviews. Example student data are shown in Figure 3. Here, Software did a particularly nice job of adding a limited number of tick marks to the high-point density spectra so t h a t Manager could easily correlate food colors with spectral profiles. Clear Plastic Spray Coating Problem. This senior course experiment is intended to illustrate the product comparison aspect of advertising ethics. Six to 12 apparently different, clear plastic spray products 1186 A

are evaluated to determine if they really are chemically different or are just marketed with different labeling and pricing. Analysis is done using FT-IR spectroscopy, and the role interaction is delightful. Software uses another computer with a set of simulated spectra to make individual product assignments, and Hardware runs the instrument’s computer to make comparative evaluations by creative baseline subtraction and pattern matching. Manager is given the ethical problem of determining whether the company should market a new spray product under its own brand name, which differs little from those already on the market. The supposition is that it would be too difficult for another company’s legal staff to prove that their own products were being duplicated. Example student data are shown in Figure 4. Here, Software and Manager were able to telemeter the raw ASCII data for evaluation by Manager from a Midac FT-IR spectrometer into the AsEasyAs spreadsheet and make multiple overlays and expansions in a highly interactive manner. Broken Pill Coating Machine Dilemma. This junior course experiment uses Software’s spreadsheet to enable Manager to choose some unique combination of elements and thus select hollow cathode lamps and solution concentrations. These choices allow Manager to determine, by AAS, to which of 14 possible bronze alloys a small (< 0.2 g) sample of yellowish “floor sweepings” may or may not belong. Manager is given the dual problem of minimizing t h e amount of time and laboratory resources needed to make the determination and deciding if the material found is actually a bronze (just a failed bearing) or an adulterant (a possible cause for shutting down the line and laying off workers for a day). Because this decision must be made quickly and it affects the economic welfare of both the company and the workers, this experiment gives students a chance to participate in crisis management. Chemist has the troublesome task of dissolving, with high precision, a small amount of a real sample in various blends of aqua regia while Hardware and Software share the problem of how best to handle the instrument and analyze the working curves so t h a t Manager can determine over what range the system is linear and thereby quickly decide whether the sample is a bronze.


Example student work is shown in Figure 5. The stacked bar graph of test element possibilities is prepared by Software before the lab. Manager uses these data to advise Chemist and Hardware about which elements must be determined to distinguish between possible bronze alloys. Possible Atomic Absorption Matrix Effect Design Problem. This crisis anticipation experiment in the senior course is cast as a design problem for the detection of a possible matrix effect in the analysis of bronze alloys by AAS in the junior course. The experiment consists of a computer - based “pseudo” expert sys tem (a sorting spreadsheet with conditional cells), 13-15 known bronze alloys with up to 15 elements in each at varying concentrations, and an AA spectrometer with a limited supply of hollow cathode lamps, not all of which are in equally good working order. Manager must decide what combination of lamps, elements, and solution conditions should be used to detect what appears to be a n element - specific matrix effect dependent on how much aqua regia is used to dissolve the native bronze standards and unknowns. This is a n excellent problem for Chemist. The dilution factors needed to make the test solutions fall in the linear regions of the AA working curves (while still varying the ionic strength and anion content of the solutions) can become so high t h a t huge error propagation problems occur. Chemist must have very good laboratory technique, and the gravimetric dilutions must be made precisely. The design ideas have to be tested as the experiment progresses, so both Hardware and Software are very interdependent as the spreadsheets evolve experimentally. Mock Robot experiment. This junior course experiment demonstrates the development of an automated method, including the l a n g u a g e needed to a u t o m a t e t h e spectrophotometer. I t also demonstrates the challenge of preparing solutions in which the analytical concentration of an acid-base indicator and the total ionic strength of the solution are both held constant while the pH is varied, so that a perfect isosbestic point can be recorded under mock or simulated robotic conditions. Using an automated scanning spectrophotometer requires preparation of a spreadsheet to record the wavelengths and absorption measurements. Software provides Manager with instantaneous evaluation of graphs in the spreadsheet. Other

--.

Braph of NBS Standard Bronzes Bruce Company May a h , 1990 E P b total ~

37a

62d

157a 162a 63 158a 164 Standard Number

Figure 5. Student data prepared by Software for Manager to differentiate between various bronze alloys in the Broken Pili Coating Machine Dilemma in the junior course.

Figure 6. Student data showing an attempt to record a “perfect” isosbestic point using brom -cresol green indicator solutions in the Mock Robot experiment in the junior course.

Note that NBS is now NIST.

Key: A, pH 5.49; B, pH 5.17; C, pH 4.49; D, pH 3.95; E, pH 3.29; F, pH 2.69.

constraints on Software, Chemist, and Hardware require a high degree of understanding and preplanning of the whole experiment. Learned, among other things, is the fact that it requires more knowledge and skill to set up an automated method than it does to do the same work manually. Example data showing one Manager’s perception of a “perfect” isosbestic point for brom cresol green are shown in Figure 6. Aspirin Hydrolysis Kinetics. In this senior course role-practicing experiment, a robot is set up and core programs are edited to weigh, dissolve, filter, and dilute one or more aspirin tablets. The resulting solution is examined for hydrolysis products by remote U V spectrophotometry over a week or more (see Part 11). Example student data are shown in Figure 7. Reduced absorbance variable data (5) were collected for two weeks to prepare the pseudo first-order rate plot shown. Remote Instrument Control experiment. This methods development experiment in the senior course demonstrates process control and monitoring. Serial A/D converters of high accuracy and good speed suggest cheap and easy operation of instruments, such as a chromatograph or a spectrometer, a t a distance for monitoring and controlling a chemical plant process or reactor. Deciding how to test this supposition, and getting a reality check on just how easy it is to do this, is the task that Man-

ager faces here. By using the same chemistry as in the junior course Mock Robot experiment, Manager can ascertain what is required of Software and Hardware to write the programs to make the A/D converter send data for graphing from a remote spectrophotometer t o the process control site computer, and to connect the site to the remote instrument using video and voice monitoring along with the RS-232 data links. The lesson is that fast, accurate, and cheap a r e mutually exclusive concepts when taken more than two at a time. Loyal Employee Productivity Dilemma. This junior course experiment demonstrates structural unem ployment by presenting students with an ethically compromised management decision. A new top -loading, serially interfaced balance alleviates the need for volumetric glassware for preparing dilutions of low ionic strength solutions in a spectrophotometric analysis using bypyridine complexation (8).It is now possible to replace the volumetric standards with a few gravimetric standards. Chemist and Hardware are soon able to tell Manager that, ‘Yes, it is really true that the time to analyze an unknown spectrophotometrically can be reduced from three hours to 20 minutes.,, Manager then is faced with a nasty decision: Should the free time be recaptured into the laboratory economy by firing or laying off the technician who used to handle all of t h e volumetric glassware tasks?

Manager has to support the decision both technically and ethically. Instrument Payment Release Dilemma. This junior course experiment demonstrates liability release. Reversed-phase LC is used to cast the problem as a n exercise in purchasing an instrument. The task is to determine if the instrument purchased is actually performing up to specifications in the analysis of aromatic hydrocarbons with a methanol/ water mobile phase. If it is, the remainder of the money set aside for its purchase can be released and the instrument accepted. Manager must decide whether to release the funds, based on input from others in the group, and only one afternoon is alloted to decide if a particular instrument will suffice for a few years’ subsequent work. Example data for two peaks in a composite chromatogram are shown i n Figure 8. Here, Manager r e quested that Software isolate these peaks in the spreadsheet (by expanding the abscissa) to allow calculation of column resolution and capacity factors. Hardware had linked the serial A/D converter t o the chromatograph through an intermediate OA buffer amplifier to acquire the data directly into the spreadsheet using a macro to drive the serial port. The senior course experiment is similar, except t h a t the choice of compounds used to evaluate the instrument, the mobile - phase composi tion, and the manner in which data


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Figure 7. Student data graphed to determine the pseudo first-order rate constant for the hydrolysis of aspirin in the Real Laboratory Robot experiment using remote UV spectrophotometry in the senior course. The data are plotted as a composite absorbance parameter (5) time. Data result from the cumulative design efforts of 10 people working over a two-week period.

are acquired are left up to Hardware (the choice being between a lab microcomputer fed by a serial A/Dconverter into a spreadsheet for graphing and a manually read strip chart recorder). I n s t e a d of d e c i d i n g whether to release payment for one instrument, Manager must decide whether to buy and locally maintain four instruments for use in an academic research lab or whether to make the necessary political compromises to accomplish the same repeated research objectives on a shared departmental instrument with maintenance done by department a1 technicians. Chemist is seriously challenged by Hardware’s decision, and Manager must decide not only whether the instrument meets specifications but also whether the choice of test mixture really stresses the instrument sufficiently to warrant the decision. Manager also struggles with the dilemma of local versus departmental control. If local control is assumed, it requires local funding. If departmental control is assumed, the instrument’s performance may suffer from use by numerous individuals.

Changes and results The role-playing construct has long since passed the proof of concept stage and is now in the process of professional evaluation in other in1188 A

Figure 8. Student data showing an expanded region of a reversed- phase liquid chromatogram. The data were taken using a serial A/D converter and operational preamplifier wired by Hardware at a data rate set by Software to be approximately 1 point for the Instrument Payment Release Dilemma in the junior course’ every These two peaks correspond to the elution of isopropylbenzeneand tert-butylbenzene using a 75/25% methanollwater mobile phase.

dustrial (9) and academic (IO) contexts. (See box on p. 1190 A for addit i o n a l e x a m p l e s . ) T h e r e is no question that its implementation at St. Olaf has caused changes. Putting together the pieces to determine what h a s changed with the new method of lab structure cannot be totally objective. It certainly has not been that way while dealing with the students! But there are many stories and some broader features that can be related that will at least signal, if not actually document, what has changed in the students’ minds, and what can be expected to accompany the method out of the St. Olaf environment. Student attitudes. From its simple beginnings a t the University of Wisconsin-Madison, student acceptance of the lab approach of interdependence has been spontaneous and positive. Sharing and contributing pieces to a larger solution, cross teaching, and managing and roleplaying are experiential devices that the students value and enjoy. There are negative responses, but they are few. Out of 200-250 students taught over the past 10 years at St. Olaf, only two or three have voiced serious objections to the approach. One student resented having to manage. The person commented, “I didn’t ask for this! I didn’t come to college to learn how to be a manager!


I want to go to graduate school-not manage!” The lab session was a disaster for this person’s group. It was only in the management interview that the person saw management as a broad concept and began to rethink this attitude. Another student dropped the junior course lab early in the semester, calling i t “phony.” Some students have sought other approaches to the junior course (required for graduation) because of what they perceive from outside sources to be its workload, and other sections have been offered under conventional constructs. The senior course is required only for the ACScertified major, and it has enjoyed nearly universal acceptance by those who have taken it. Many positive changes have been observed in students’ approaches to the analytical discipline. One has been a new attitude about lab preparation. Students now regularly call “staff meetings’’ before they come to lab. Managers take their responsibilities seriously and have been genuinely distressed when “their people” didn’t take them seriously or didn’t “get their stuff together” before the lab. Reports are usually in before the end of the lab or, at worst, before the next session. The old problem of having a majority of reports appear a t the very end of the semester has all but ended.

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Labs that Upper Management previously found demanding to teach a n d t h a t s t u d e n t s were anxious about taking have now actually become pleasant places in which t o work. Recently the final exam ended the lecture part of the junior course a t 11:OO on a Friday, three days after the lab had been checked out. At 1:30 that afternoon, two Managers were found back in the lab working on the computers! When told t h a t t h e course was over, that there were no more problems to work on, and that the computer was being shut down, discussion followed for most of the afternoon about what a great time was had and how sad it was that “a person couldn’t make their living having this much fun!” Innovation has increased in the lab. Some solutions to the problems are remarkably clever, such as regressing an entire spectrum on another over 500 wavelengths! Some solutions to get people to come to lab on time are also innovative, such as promising food (usually pizza) or a ride. Most such innovations are allowed by Upper Management, except for one case in which a Manager a t tempted t o subcontract the whole problem to another company in return for food. Analytical results are generally good. Productivity has increased, and quality has not particularly suffered. Managers with sloppy or cavalier a t titudes generally get poorer results than those who convey to their people the importance of doing a good job. Experiments that used to take three periods can be done in two and occasionally in one. When planning is done before the lab and roles are und e r s t o o d , good r e s u l t s h a p p e n quickly. There may be needs here that cannot be determined over the short haul. Statistical databases are evolving, and final evaluation of the net analytical quality of the work will take several years. But, for the short term, students teach each other what they are doing, Managers work hard on communication, experiments are read, and results are generally good. There is in this structure a reason for studying the lab that has been previously missing; here, the students are influencing each other and they care about doing well for their buddies. Computer-based attitude changes. The computers in the roleplaying labs perform several functions. One function that is a key to developing good small-group dynamics is information exchange. The need to document and report to oth-

ers the lab results becomes a key social force for doing good work and telling others about it. This is more of an attitude than a skill, although the two are definitely related. The lab microcomputers catalyze good lab practices and have taken on the role of a technical watering hole during each lab period. Safety. Because it is Manager’s responsibility t o i n s t r u c t others about all aspects of lab and chemical safety, the students pay much more attention than they did when safety was just preached from the front of the room. Gathering MSDSs and translating them into the local experimental context has added a new reason for understanding descriptive chemistry, as has the need for Chemist to be responsible for waste disposal. Attitudes about both topics have improved. Reverberations in the lecture halls. Lectures in the junior and senior courses have changed, both in delivery and in sequence, by reverberation from the role-playing laboratory structure. Philosophically, it makes no sense to leave decision making and interaction out of the lecture portions of these courses when they are so thoroughly woven into the lab portions. Similarly, there is a strong need to use lecture time to establish the theoretical bases for the chemistry done in the lab, especially because the problem - solving base in the lab occurs so rapidly a t the end of the sequence. Some course developers have felt that the lab should be correlated to the lecture so that the principles discussed in the lecture can be seen by demonstration in the lab. In these courses, the opposite is the case; the lecture has to correlate to the lab so that there is sufficient theoretical material at hand in the lab to make problem-solving decisions. Similarly, Hardware needs to understand the basis of the instrumentation that will be used in the lab, simply because that information is not usually provided in an understandable format in instruction manuals. Chemist needs descriptive chemistry, simply because Chemist will have to advise Manager what t h e repercussions are, in a oneperiod schedule, if certain kinds of chemistry are or are not attempted. These lecture reverberations have been active for so many years that both junior and senior course lectures are now set up, books are selected, and problems are assigned with three factors in mind. The top priority is the communication of pro-

fessionally accepted conventional wisdom in modern analytical chemistry. This is followed by applicability to and support of the role-playing laboratory. The last priority is the advanced or intricate nature of the material (i.e., the cleverness factor) that often makes for the design of challenging examinations and problem sets. If the role-playing lab experiments are too simplistic or contrived, then the lecture material directed toward their mastery will be too dilute and the students ultimately will suffer professionally. This means that the experiments must have enough honest challenge that classroom study occurs at an appropriate level of complexity. Course textbooks must support such study and communicate (for purposes of future exam performance outside the course) conventional professional wisdom. Performance on exams is a t about the same level it was prior to development of these classes.

Impressions The results to date of the role-based model for teaching analytical laboratories are far better than originally expected. Students have taken hold of the concept and run with it and are now the primary motivators for its continued development. The fact that a complete equipment set has been made available to each company has enhanced the overall effective ness of the approach. Students have reacted enthusiastically to making their own plans and setting their own schedules. The roles themselves have r e vealed interesting perspectives. Surprisingly, the most troublesome role has been Chemist. Many analysis errors are directly traceable to Chemist. At the same time, these errors are often discovered earlier and more learning is taking place as a result. There is room for learning from mistakes and, although they are not acknowledged with enthusiasm, this model allows mistakes to be accepted and owned. Manager can approach errors more objectively than was possible in the previous competitive and isolated lab format. One important concept worth noting is that good results are dependent on more than just good technique and good instruments. If the experiment is sufficiently ambitious, it is best solved with interdependent efforts. Good results come from, and do indeed depend on, good management. Students see and understand this concept.


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Me1 Koch is head o f t cal Sciences Division at

1 chemistry aspects of anaemistry. Second, the mc barrier to a new employs is the ability to work as eam. I believe this probbecause our educational

11 be used to char

-ts have been encour

departments to change one two things in their curricuL what would you suggest

lower levels (Quantitative Analysis pany and is currently supervis +heAtomic Spectroscopy Secti 4nalytical Technology Div Q

lack of appreciation for safety, en ronmental concerns, and quali This improves slightly wi vanced degree. Walters’ s are an exception as they se concerns throughout their Allen: Feedback from a h d e n t s suggests t h a t should be able t o solve This means they need to communicate to help others un stand the problem (define it) an

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way that the young chemist sees both t h e aDplications a n d t h e thought processes needed. Eierman: Incorporate tive goal structures, which would require students to work together and communicate in order to SUCceed. Students should be encourintellectual pursuits. Ekimoff: I would that at least one course in classical analytical chemistry 1: ‘,au--’-*


I t remains to be seen if roleplaying as it has been used in our group constitutes “learning together” ( 1I), because interdependent interaction does not require individuals to diminish their unique identities as part of decision-making compromises. In fact, the division of responsibilities suggests that t h e more unique an individual the better, as long as that individual is accountable for his or her role. Diversity of the individuals is valued.

Conclusions A recent US. Department of Labor report (22)from the Secretary’s Commission on Achieving Necessary Skills (SCANS) addresses “the demands of the workplace and whether our young people a r e capable of meeting those demands.” Almost all features of the five competencies listed in the report as necessary for h t u r e success in the workplace are similar to the interdependent skills that form the core of these role-playing laboratories. According to the criteria set forth in this report, the roleplaying labs are meeting the SCANS requirements for the future. Role - playing in small interdependent groups is an improved method for teaching analytical chemistry at many levels; it increases students’ “ownership” of the analytical experience. References (1) Astin, A. W. Liberal Education 1988, 74,6. ( 2 ) Safety in Academic Chemistry Laboratories; American Chemical Society, Committee on Chemical Safety: Washington, DC, 1990. (3) Hughes, J. C. “Testing of Glass Volumetric Apparatus”; NBS Circular 602: U.S. DeDt. of Commerce: Washington. DC, 1956. (4) . , Ramette. R. W. Chemical Eauilibrium and Analysk; Addison-Wesley: New York, 1981; pp. 176-87 and 644-47. (5) Connors, K. A. A Textbook of Pharmaceutical Analysis, 2nd ed.; Wiley I n t e r science: New York, 1967; pp. 187-90. (6) Garrett, E. R. J. Am. Chem. Soc. 1957, 79, 3401. (7) Lavine, R. R., University of WisconsinMadison, personal communication. (8) Sandell, E. B. Colorimetric Determination of Trace MetaZs, 3rd ed.; Wiley Interscience: New York, 1959. (9) Hughes, G., Dow Chemical Co., personal communication. (10) Eierman, R. W. University of Wisconsin-Eau Claire, personal communication. (11) Johnson, D. W.; Johnson, R. T. Learning Together and Alone; PrenticeHall: New Jersey, 1991. (12) “What Work Requires of Schools-A SCANS Report for America 2000”; U.S. Dept. of Labor, secretary’s Commission on Achieving Necessary Skills: Washington, DC, J u n e 1991. V

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There have been a few key players in the development of this approach over the past 20 years. Foremost is Merle Evenson, who supported the philosophy through many years of criticism. Dick Schedtler and the Stephen Ministry taught me role-playing. I’d-also like to thank Robert Lavine, John Wright, John Schrag, Pat Brinkman, and Dave Coleman at the University of Wisconsin-Madison; and Wes Pearson, AI Finholt, Jon Moline, and Scott Narveson at St. Olaf College. Many University of WisconsinMadison research students and teaching assistants played roles ranging from devil’s advocate to champion. Bob Schmelzer, Bob Lang, and Ted Weigt built much equipment for the labs. Maren Bunge, Scott Koehler, John Koch, Marin Amundson, Steve Higgins, Dan Higgins, Bruce Gutzmann, Sandy Schlesinger, Dean Plumb, and Amy Jo Nelson made the difference at St. Olaf College. The Johnson’s Wax Foundation, The Amoco Foundation, The 3M Foundation, The Apple Computer Foundation, The Hughes Foundation, and The Dow Chemical Company Foundation contributed either funds or equipment. Carolyn Carter, Departments of Chemistry and Education at The Ohio State University, a n d S u s a n Olesik, Department of Chemistry a t The Ohio State University, prompted and contributed to this manuscript. Me1 and Joanna Koch contributed perspective. Chuck Huff provided background information on the Hawthorne effect. I especially acknowledge the more than 3000 undergraduate students who thought enough of the idea to “sign up” and play the game with me over the past 25 years. They are the ones who made it work. This information was presented in part at the 10th International Conference on Chemical Education at the University of Waterloo, Waterloo, Ontario, Canada, Aug. 20-25, 1989.

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As a teenager, John P. Walters (standing) was inspired to become an analytical chemist by Lee Dillenbeck, an analytical chemist in the company where Walters’father worked. After graduating from Purdue in 1960, he studied time-resolved emission spectroscopy under the direction of Howard Malmstadt at the University of Illinois. After completing his Ph.D. in 1964 and a teaching post-doc with Malmstadt in 1965, he joined the faculty at the University of Wisconsin-Madison, where he supervised 17 Ph.D. and 17 M.S. students and pursued research in emission spectroscopy. He joined the faculty at St. Olaf College in 1982 and is still teaching f i l l time. Also pictured are students Jeff Bottin and Holly Schroeder.


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Role-playing analytical chemistry laboratories. Part III: experiment

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