%ere was a maH who devoted his f#e to worki~g with chemicafs . . . a i s cu6ic style must have 6 e e ~ based OM a kmufedge of crystaffographic systems, a d his use of coforsimpfies a kmwfedye of spectroscopy )’
PICASSO THE CHEMIST
ACS Fisher Award Address Philip W. West Chemistry Department Louisiana State University Baton Rouge, La. 70803
Because I never graduated in chemistry, I hope I can be forgiven for not knowing what chemistry is all about. My undergraduate composite majorminor in chemistry, geology, and engineering was fun, but I did not seem to learn the right things. Then, for my PhD, a degree in microchemistry was invented so I could be dismissed with dignity. Again, bacteriological, medical. and engineering training cut in on a chemical education. Now, after seeing what the freshman course in modern chemistry covers, I doubt I’ll e\ver know enough t o earn a living as a chemist . To make matters worse, I chose t o be identified as an analytical chemist. Then some years ago, I was assured t h a t all analyses could and would be done by X-ray spectrometers, spectro784A
graphs, and countless other tools having buttons, dials, and digital readouts. T h e great universities of this country either had no analytical chemistry courses or realized their folly and declared “analytica non grata,” and turned t h e teaching of analysis over t o the talented members of their faculties. Of course, I now wonder what I’ve been doing all these years and why. I’m not sure I know a good definition of chemistry, nor a m I sure t h a t I know who is a chemist. I’m confused when I hear ads extolling t h e merits of products t h a t contain no chemicals. B u t then I ask myself, “Why not products without chemicals when I see so many chemistry courses t h a t have been purified to the point they too are free from chemical taint?” In my confusion I had once thought t h a t all matter was chemical and t h a t chemistry was a n experimental science based largely on the manipulation of chemicals. In a belated attempt to learn more about chemistry and its significance, I have noted t h e courses in chemistry that are required in different fields. The curricula gave t h e impression t h a t agronomy, nutrition, sanitary engineering, poultry science, medicine, and many, many other fields require a knowledge and practice of chemistry. Needless to say, I was impressed and pleased. T o better understand why these fields need chemistry, I then looked at
A N A L Y T I C A L CHEMISTRY, V O L . 46, NO. 9 , AUGUST 1974
the chemistry department catalogs to see what content was projected for t h e first or basic chemistry courses. Further enlightment came from five or six feet of freshman chemistry texts. Looking a t the freshman texts t h a t had been published since 1972, I was amazed to learn t h a t our farm specialists and engineers were being educated to the high standards of our own chemistry majors. Few, if any, were being pampered with topics t h a t could easily be related to what they had seen, done, or would later use in practicing their professions. T h e whole lot was to be brought u p to proper intellectual levels by putting them a t the top of t h e knowledge ladder where they could understand everything whether they knew anything or not! We have undertaken to give the ag boys and engineers intellectual respectability! I have always had a secret desire to be a physicist or mathematician, free from stinks, mess, and tedious labors. Now I realize I was born too soon. Chemistry students of t h e enlightened present are sheltered from laboratory tedium-they are being educated to be philosophers and theoreticians. Truly, the intellectual elite! Quantum chemistry, kinetics, and thermodynamics. What powerful tools t o p u t in the hands of freshmen! Think of a young Ms., majoring in home economics who knows all about t h e quantum levels of the sodium that’s in the baking soda, NaHC03 (or
Report
Bald painter before his easel; at left, a model in costume. Picasso, 1927 Courtesy of Los Angeles County M u s e u m o f Art
was that Na2C03?). I’ll bet she never bakes a cake that falls flat-she will know too much kinetics to let t h a t happen. Think also of the premedical student who hears about the pills t h a t have two buffers. He’ll understand how di-buffers work; probably some thermodynamic gymnastics are produced to insure two p H levels-if the first p H doesn’t eliminate the gas, the second one surely will. And the ag student will really benefit because he will know all about calcium carbonate-the quantum levels in the calcium and the carbonate (whatever t h a t is) and the crystal structure will be crystal clear to him. T h e nice thing about the presentation, I’ve observed, is t h a t the student doesn’t need to worry about what happens to the crystal structure when the calcium carbonate is heated. Probably something happens, but it can’t be very important because no mention of it is made in the text. Having spent my professional life in the laboratory (driving students but not working myself, admittedly!), it seemed time to talk to some colleagues about chemistry. I, thus, gathered some of the facts of scientific life. It seems that so much is known that no one can know it all. so why try? With theory and a computer, or even a calculator, all sorts of interesting deductions can be made and used to impress students and even colleagues. I did sense a bit of disdain for the experimentalist, but there was a determined
resignation to be noted whereby good theory was not to be wasted just because of bad data. For example, cited values for any given equilibrium constant may vary by a factor of 2,5,10, or 1O4-or lo1’ for Al(OH)3. Such discrepancies, however, are easily disregarded and do not preclude the use of activity coefficients. Furthermore, it should be realized t h a t activity coefficients have special value in helping eliminate some of the less active students. In some universities analytical chemistry is still taught and a t times is even identified as such. Quite often, it is upgraded to a more respectable status by sequestering it with more enlightening material and giving it a more dignified name. Because some students succeed in passing the first year course, it seemed logical to look a t some typical courses in analytical chemistry. This was a good idea because it gave a real insight into what chemistry is all about. I understand now what I was told a few years ago. Chemistry is X-ray spectrometers, emission spectrographs, polarographs, electron microprobes, NMR, ESR, EPA, and ESP. A chemist is a man who knows where his electrons are and can pour beer in a boot, first or second hand, without spilling very many drops. From what is taught and said, I am convinced that chemical analysis is now a process of dipping a couple of electrodes into a solution, spraying a
solution into a flame, or pouring a sample into a tube and inserting the tube into a green box (people are sensitive about the term “black box,” and there is a determined swing to green, blue, or tan). How sweet it is! What is really impressive is the fact that one box can turn out hundreds or even thousands of answers in a matter of days or even hours. This takes the guessing out of analysis since the boss might question one or two numbers, but who can dispute 10,000? Certainly, there can be no doubt when the box has a digital readout or even an integrated recorder. Furthermore, because the box is carefully identified as an NO2 monitor, a total sulfur analyzer, or a formaldehyde determinator, there can be no question about what is being measured! The most convincing observation might very well be the fact that no analysis need be done with anything costing less than $5,000 and with reactors, computers, etc., millions can be spent! In spite of the impressive sophistication of our general chemistry courses and the elegance of our analytical devices, I long a t times for the good old days. It is hard for me to believe that everything we used to do was so bad that it all had to be replaced. Some chemical reactions are important to some people, surely, and why shouldn’t students be permitted to see what the colors are of salts of some of the transition metals? If chemistry sets are great Christmas presents, why
A N A L Y T I C A L C H E M I S T R Y , VOL. 46, N O . 9 , AUGUST 1974
785A
Why ut pruducts withuut cheMicafs wheH . . . su MaHy cheMistry cuurses have beetz purqied tu the puht they tuu are free f r u cheMi ~ caf taiW ’’ “
can’t chemistry laboratories be instructive and even fun? Must theory replace experiment, observation, fact, and deduction? I t isn’t analytical chemistry t h a t is being taught now: it is chemical analysis. We are training analytical physicists, and I’m not sure t h a t I like it. I personally am upset when I see the analytical concept limited to the final measurement step. In the days of old fashioned analytical chemists, t h e analytical process was a complete operation of sampling (why, what, and how), sample processing, separations, and finally, the measurement. T h e elegance of the measurement now tends to impart a false security which may be deceitful. For example, one of our clients on some consulting work recently questioned our values for ozone when two independent groups within their own company agreed on values of zero. Both groups were using chemiluminescence-type monitors, so how could they be wrong? After a searching discussion and inquiry, it was found that samples had been pulled through considerable lengths of rubber tubing-a sure way to remove any ozone that might originally have been present. In another instance, a difference in results was resolved when it was found t h a t a beautiful instrument was used without calibration. There is a fascination attached to some of the physical methods of analysis. For example, X-ray fluorescence presents the possibility of determining many metals in a sample without separation or other processing chores. No matter how the metals may be combined: whether they may be as oxides, 786A
A N A L Y T I C A L C H E M I S T R Y , VOL
silicates, sulfides, chlorides, or whatever, they can still be identified and measured with reasonable accuracy. Although the equipment is still quite expensive and the technical support required is considerable, t h e method would make possible t h e screening of thousands of airborne particulate samples per month. If 10-15 metals were to be determined on each sample, the amount of data collected would boggle the mind. After all, the data would have to be interpreted, and even computers would be unable t o appraise the health hazards indicated by a sample that showed, for example. the presence of chromium and beryllium. Both metals are known to be toxic and carcinogenic. Yet, if they were present in the form of emerald dust, it is doubtful that there would be much to worry about-emeralds present more of a financial hazard than a health risk. There can be no question regarding the value of present analytical tools. Never in the past has it been possible to even come close to the depth and breadth of information t h a t can be obtained now. If this is true, is there a complaint and if there is, what is it and what can be done about it? I personally do think there is a complaint-chemistry, or rather, the lack of chemistry. Of course, not everybody agrees with me, nor d o they accept my concept of chemistry and its importance. I must admit t h a t I do not feel t h a t quantum chemistry, kinetics, and thermodynamics is chemistry. A part, yes, but without some basic background in chemical reactions, properties of chemical substances. and a bit of descriptive chemistry, I feel t h a t the student does not have a proper foundation and his knowledge is quite useless except for certain types of graduate work. Even then, it seems dangerous to do graduate work in chemistry without knowing how to make up standard solutions, do stoichiometric calculations, and sense whether or not certain mixtures are compatible. Why we are doing what we do may be explained in a number of ways. For one thing, intellectual smugness has played a part-to be theoretical 46. NO. 9. AUGUST 1974
implies mental maturity, and those of us in the educational field progress by convincing the administration that we are mental giants. Then, if we can convince ourselves that it’s too expensive, too time-consuming (and too much work) to retain the laboratory approach to teaching chemistry, then we either teach theory or close up shop (and lose our jobs). Then, also, there is the interesting position of analytical chemistry in the education process. I think that an honest evaluation would disclose to most t h a t the major portion of inorganic chemistry and basic chemical principles has been taught in the past in the courses of analytical chemistry. When analytical courses were dropped and analytical professors were run off. the void could not be filled from the more intellectual core of the chemistry departments. Now there is a resurgence of analytical chemistry, There is a realization that analytical chemists are practical people and can take a job outside of the university and come close to earning their pay within a year or so. Unfortunately, the analytical professors now want to teach analysis, not chemistry. And why shouldn’t they? The old laboratories where chemistry was really taught were, and still are, downgraded. Two or three hours of laboratory teaching yields one hour of credit on the teaching load. The raw recruits and low rank faculty do the dirty work ( ? ) of teaching the laboratories. Why, oh why, should a proud analytical man go back to the good old days? If, and I do mean if, t h e people in life sciences, engineering, and agriculture should tell us t h a t the chemistry department is a service department and is important to them and their curricula, and if we in chemistry should decide t h a t our own students might want to work as chemists and not necessarily be prepared to get PhD’s and teach, then how might we put the laboratory back in chemistry and put more practicality into our basic courses? The first change I would recommend is to give proper credit and proper recognition for teaching chemistry laboratories. One hour of teaching credit for one contact hour in the
laboratory would certainly help! Also, if chemistry is really an experimental science, why not put senior faculty in the laboratory? T o me, a most impressive bit of news was to learn that when the distinguished chemist Norman Hackerman became president of Rice Institute, he elected to teach freshman chemistry. After being in the president’s office for a couple of years, what is Dr. Hackerman doing now? H e is teaching freshman chemistry laboratory! He terms this “eyeball teaching” and feels it offers real rewards. After giving teaching credit and proper recognition, what next should be done? With a new stature for laboratory teaching, why not expect a new, vital set of laboratory courses? Nothing much really new, except some new gadgets in analytical laboratories, has been introduced in teaching basic chemistry in decades. T h e freshman laboratories drag on along the lines of high school experiments. Quantitative experiments, if modernized, are mainly pretty gadgets applied with a minimum of accompanying chemistry. Basically, it’s the same old classic wet chemistry, dull and tedious. Almost any laboratory course now seems unrewarding-a semester of laboratory work is invested in 15 or 20 reactionsnot a very intensive introduction! T h e question then arises: what, if anything, can be done? Within the limits of this address, the only comments that can be made are a suggested approach to the freshman laboratory. This approach has been fun for me and fun for the students. So far, the course is for majors in our College of Chemistry and Physics and consists of six hours of laboratory and one hour of lecture for one semester. I t follows a semester of introductory laboratory and is independent of the regular lecture presentation and the text used for the regular lectures. T h e text used for the laboratory is self-sustaining, and the basic philosophy involved is apparent from the title, “An Experience Approach to Experimental Chemistry.” (Philip W. West and Roberta Bustin, “An Experience Approach to Experimental Chemistry,’’ T h e Macmillan Co., New York, N.Y., in press.) T h e results obtained with the new presentation have been more than gratifying.
The basis of “An Experience Approach to Experimental Chemistry” is presented in a preface to the text: “Chemistry is a n experimental science. Laboratory work is an essential part of applied chemistry and, is therefore, the basis from which most of our modern high standards of living were developed. “There is no quick way to become a chemist. Simply reading books and learning chemical theories can no more produce a true chemist than learning the theory of music can produce a real musician. A true chemist must d o hundreds of experiments and make countless observations in order to gain the experience t h a t will provide him with the necessary experimental background and intuition for him to use chemistry successfully. T h e situation is analogous to t h a t of the professional golfer who must spend countless hours learning how to make different kinds of shots in order to gain the necessary experience for making judgements as to when and where given kinds of shots should be attempted. Similarly, it is only through practice and experience t h a t one can become a concert pianist, a commercial pilot, or a physician. “We have endeavored to make the study of chemical reactions a n enjoyable experience. We have tried to take boredom out of the laboratory by setting a fast pace for the experimental studies. We have also attempted to relate experiments to current problems such as crime detection, studies of medicine, applications of chemistry to industry and the study of environmental problems. It is important to realize that almost without fail, experiment precedes theory. Because of the broad experiences t h a t will be gained from these laboratory studies, the subsequent introduction to chemical theories will be easier and more exciting because the theories can be related to observations and experiences that have already been met. This experience approach to experimental chemistry offers you the challenge of exploring the unknown, the thrill of discovery, and the satisfaction of accomplishment. These experimental studies should stimulate you to make careful observations, critically reflect upon the significance of observed phenome-
na and establish the ability to seek reasons and conclusions. In the laboratory, you should observe many things that cause you to wonder. Although none of us will ever find answers to all of our questions, we all find satisfaction as we grow and learn and finally understand. “As mentioned before, experiment almost always precedes the theory. Theories are developed to explain experimentally observed phenomena. In practice, theory is learned to provide guidance in the solution of problems. Where theory may lead to the solution, it is only after experimental verification that the answer derived can be accepted in good faith.” What makes this a new approach to teaching chemistry? Speed, relevance, and fun! The speed permits a student to see 600-700 reactions, and many of them are repeated a number of times under different circumstances. This large number of observations is made possible by using spot test reactions, ring oven techniques, and other efficient methods for working with reaction chemistry. The relevance is illustrated by a bit of forensic chemistry which is included in the presentation of various reaction types. Under catalyzed reactions the student learns about the special case of enzymatic reactions. Blood is detected by the peroxidase test. Because organic chemistry is included when appropriate, students even hydrolyze an ester.
“CheMistry studeflts of the ethyhtefledpresefit are shefteredfroM faboratory tediiw-they are beiizg educated tu be phifusuphers atzd theureticiam ’’ A N A L Y T I C A L CHEMISTRY
VOL. 46,
NO. 9 ,
AUGUST 1974
787A
‘‘. . . oize 601 caH turiz out huizdreds ur eueiz thousaHds of aizswers iiz a Matter uf days or eueiz hours . . the boss Might questioiz oize or two izu~bers, but who caiz dispute70,000?”
They don’t use two days to reflux t h e ester with caustic; they d o the job in 30 seconds by adding an esterase. Why not? By the end of t h e semester, students can take a sample of airborne particulates collected on filter tape and determine four metals on a spot of dust one-half inch in diameter. T h e four determinations are completed in a three-hour laboratory period with errors no more than 20-30%. The total dust sample probably weighs less than 40 fig. A great deal of fundamental chemistry is covered, together with some important concepts and associated operations. Reagents and their characteristics are studied to establish a realistic understanding of their value and their limitations. T h e study of reagents includes determining sensitivity and selectivity. Techniques for conditioning and eliminating interferences introduce the practical aspect of problem solving and lead the student to the conclusion that even relatively poor reagents may be very useful when properly used. They also learn t h e value of distrust when they are given a nickel reagent, for example, and then find that it also reacts with iron, copper, and cobalt, as well as with other less significant metals. Students truly have fun with the development of reliable spot tests. T h e work involves the study of dithiooxamide as a reagent for copper. They test t h e reagent with about 50 ions and find t h a t it reacts with a number of metals and there are some interferences of critical importance. They learn that, in addition to the adverse effects of reactions with metals other than copper, a second type of interference occurs when certain anions are present. When excess tartrate is present, for example, the test for copper is completely inhibited. 788A
They recognize this as an example of masking and t h a t it is due to complex formation. Having already studied complexation as a reaction type and having also studied the analytical uses of coordination chemistry, students quickly set about solving t h e problem of designing a reliable spot test. By constructing a table of cations t h a t react with the reagent and of anions t h a t inhibit the respective cation reactions, students deduce t h a t a highly selective test for copper is obtained by using malonate as a masking agent. Malonate decolorizes any objectionable iron I11 t h a t might be present and prevents any interfering reactions that would result from the presence of nickel 11, cobalt 11, or manganese 11. U’hen asked if the reagent could be used for nickel, they note t h a t tartrate masks the reactions with copper, which would be an obvious critical interference. Fortunately, most other significant interferences are also masked by tartrate. Iron I11 remains as a nuisance because of its color, but it is soon apparent that fluoride can be added to decolorize the iron without affecting the nickel-dithiooxamide reaction. Space does not permit discussing the course in detail, but the concept of standards and standard solutions should be mentioned to show how it is presented as an experimental operation. As part of an introduction to gravimetry and titrimetry, students determine chloride by the Mohr method. They learn t h a t the silver nitrate used for the titration must be of known strength. They find t h a t such a standard solution requires t h a t two facts must be known-the exact weight of some pure substances and t h e corresponding exact volume related to this weight (titer). Having experimentally established a titer, they see they can then calculate any other desired titer (e.g., C1-titer) or t h e molarity or normality of the solution. Only two experimental approaches are available for obtaining an exact weight-to-volume relationship. T h e first, dissolving a n exact weight of pure chemical and
A N A L Y T I C A L C H E M I S T R Y , VOL. 46. NO. 9 . AUGUST 1974
making u p to a known volume, is valid for AgN03 which can be obtained four nines pure. They thus make u p a standard solution with a known AgN03titer, and they then calculate the C1titer and the normality. T o verify their information, they next learn to standardize solutions. For their silver nitrate solution, a number of possibilities are considered. T h e weight of pure substance obtained from a known volume of solution is most obviously either the AgC1-titer or the Ag-titer. The experiment in either case introduces the technique of gravimetry. T h e results obtained are converted to terms of the C1-titer and normality and thus are compared to the prior values. Finally, the weight of pure substance that exactly reacts with a known volume of solution is demonstrated by the titration of primary standard sodium chloride. T h e KaC1titer is converted t o the C1-titer and normality, and if any disagreement is evident between t h e three sources of information, the student is faced with the painful, but typical, problem of resolving the difference. A full schedule of traditional gravimetry and titrimetry admittedly instills laboratory disciplines, but days and even weeks must be invested in familiarization with a relatively few reactions. Unfortunately, we have been guilty of making this a frustrating and boring experience. We have thus embittered many students and contributed to a general distaste for experimental chemistry. A practical supplement to classical analytical methods is the ring oven technique (H. Weisz, “Microanalysis by t h e Ring Oven Technique,” 2nd ed., Pergamon Press. London, England, 1970). This microchemical method utilizes chemistry for both qualitative and quantitative analyses. I t is remarkably fast and fun and is ideally suited for general chemistry laboratories. T h e simple technique is learned in minutes, and even quantitative applications are quickly mastered. Sorry, almost forgot about Picasso! Here was a man who devoted his life
to working with chemicals. So far as I know, he never studied chemistry, b u t since he applied chemicals in his work, I suppose he could have been identified as a chemist. After all, he probably knew as much chemistry as many of our recent chemistry graduates. His cubic style must have been based on a knowledge of crystallographic systems, and his use of colors implies a knowledge of spectroscopy. I wonder how much better he would have been if he’d have had a modern chemistry course with its quantum chemistry, kinetics, and thermodynamics! Presented a t the Division of Analytical Chemistrx. 167th Sleeting. ACS, Los Angeles, Calif., April 2 , 1974.
Philip W. West is Boyd Professor of Chemistry and Director of t h e Institute for Environmental Sciences a t Louisiana State University in Baton Rouge, La. Professor West was awarded the 1974 American Chemical Society Award in Analytical Chemistry (sponsored by Fisher Scientific Co.) and specifically cited for his contributions to analytical chemistry in the areas of education, forensic chemistry, environmental pollution, highfrequency oscillometry, spectrophotometry, microanalysis, a n d spot tests. Much of his background is mentioned in his Award Address. In addition to his teaching and research activities, Professor West is editor of Analytica Chimica A c t a and is a member of the editorial staffs of C‘omprehensiue Anal.vticai Chemistr?, and Mikrochimica A c t a . H e has served on the Advisory Board of ANALYTICAL CHEMISTRY and was author of the biennial review o n inorganic analysis for many years.
You can watch the noise disappear from around weak signals in this dramatic signal-averaging demonstration in your own lab.
Sig nal-averag ing eq u i pment doesn’t have to cost $1 0,000 to $15,000 anymore. If you’re doing analyses requiring the extraction of relatively weak signals from a sea of noise, you’ll be interested in our new modular signal averager. Priced at only US$2915”, the Ortec 4620/23 offers you a lot more than low cost. On any scope you have available, it displays a constantly calibrated true arithmetic average, so you don’t have to count the sweeps and calculate the average, or use an approximation. Now about the demonstration. We’ll be glad to bring a 4620123 system to your lab, complete with a signal/noise generator, and let you watch the noise melt away before your eyes. Or you can hook it in to your experiment in NMR, molecularbeam time-of-flight analysis, phosphorescence decay, pulsed
E ORTEC
ultrasonics, or many other applications in which you’ve previously had to resort to large signal-averaging computers. To make an appointment for this demonstration, call Jim Mougianis at (61 5 ) 482-4411 . Ortec Incorporated, 110 Midland Road, Oak Ridge, Tenn. 37830.In Europe: Ortec Ltd., Dallow Road, Luton, Bedfordshire, England; or Ortec GmbH, Herkomerplatz 2, 8000 Munchen 86,W. Germany. *U S and Canadian price. 1.0 b Oak Ridge, Tenn.
AN&&EB~B COMPANY
5927
CIRCLE 181 ON READER SERVICE CARD
A V A L Y T I C A L CHEMISTRY VOL 4 6
NO 9 AUGUST 1974
789A
