Editors'Column Why there's no better acid than a Corco acid. Looking Ahead A N A L Y T I C A L C H E M I S T R Y begins
t h e decade of the 1980's with a new editor and a new look. On the cover is a new logo. T h e contents pages and the beginning pages of major features and sections of t h e magazine have also been redesigned. These changes are only the most visible ones. T h e publication plans to carry forth with renewed vigor its commitment to be t h e leading broad-based publication in its field. See page 1, this issue, for comments from new editor George H. Morrison. T h e aims for t h e magazine section include publishing more articles exemplary of analytical chemistry's role in the real world. T h e publication is geared to serve not only the analytical research community, but also those who most urgently need to know of analytical developments t h a t might be applied to their own particular problems. With the help of workers in t h e field and the newly appointed panel, THE ANALYTICAL A P P R O A C H will be ex-
panded over the year to encompass more articles. In addition, staff-written material of an application nature will comprise an important part of the FOCUS section. A newly enlarged ad hoc committee on Regulations formed under t h e auspices of the ACS Analytical Division will provide information to keep readers informed of aspects of regulations which impact on both the industrial and university analytical communities. T h e publication will also continue its efforts to keep readers up-to-date on the developments in analytical chemistry by publishing state-of-theart reviews of established and emerging techniques in both REPORT and INSTRUMENTATION articles. Toward t h e end of 1979, t h e JOURNAL began t o publish classified ads listing positions open and jobs wanted. This should be a real help to employers who need to expand their analytical capabilities and also to those job seekers who have specific analytical and problem-solving talents to
analytical chemistry offer. Rates and further information are available by writing to ANALYTICAL C H E M I S T R Y , Classified Advertis-
ing Dept., 25 Sylvan Rd. South, Westport, C T 06880 Finally, readers are invited to share their reactions to published magazine material and their thoughts on t h e profession and a t t e n d a n t activities by writing to the editor. Comments likely to be of broad interest will be published in the LETTERS column. Analytical I n s t r u m e n t s Dataquest, a subsidiary of A. C. Nielsen Co., has prepared under contract to Centcom, Ltd., advertising management for American Chemical Society publications, a study entitled " T h e 1980 Market for Analytical Instruments." Historical data for both U.S. and foreign markets for analytical instrumentation are provided along with forecasts for sales to 1983. In the next five years, analytical ins t r u m e n t sales are expected to grow faster in foreign markets (15.4% compound annual growth rate) than in domestic (14.4%) continuing a pattern set a decade earlier, though the difference in growth rates is not now so wide. Growth factors such as the effects of inflation, currency devaluation, and government regulations are taken into account. Data are presented in t h e context of these factors which impact on the market by general product segments, individual products, and market segments. Copies of this study are available for $500 each. Further information can be obtained from J a m e s Byrne, Centcom, Ltd., GSB Bldg., Suite 510, 1 Belmont Ave., Bala Cynwyd, PA 19004. 215-667-9666. Josephine M. Petruzzi
All Corco acids are certified reagent grade acids. We've been specialists in reagent grade acids since 1953. And we've built our reputation on meeting the requirements and specifications of our customers, ACSandASTM. Corco can provide reagent grade hydrochloric, nitric, sulfuric acids and sodium hydroxide—plus acetic, fuming nitric, fuming sulfuric, hydrofluoric, perchloric and phosphoric acids. Also bases, solvents and specialty chemicals. When you require the highest purity, you can rely on Corco to deliver. From pints to tank trucks. Write, call or circle the number for more information.
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ANALYTICAL CHEMISTRY, VOL. 52, NO. 1, JANUARY
1980 · 29 A
Jeanette G. Grasselli The Standard Oil Co. 4440 Warrensville Center Rd. Cleveland, Ohio 44128
Operation Super-SleuthA Mirror onSocietaland | Scientific Progress T h e Chinese have a long and varied history. Over the years they have de veloped an intriguing curse—"May you live in interesting times." I am sure you will agree t h a t the period since World War II has been an "in teresting" time as defined by the Chi nese. It has been an era of enormous change in our country. We have seen great economic growth, accompanied by social upheaval. It has been a time of innovation and tremendous oppor tunity for all of us. Over a part of this post-war period I have been presenting a talk called "Operation Super-Sleuth" to various audiences of scientists and the general public. I chose the theme "Supersleuth" because solving analytical chemistry and spectroscopy problems is very similar to police investigation work. Don't we all love the classic mystery stories—Sherlock Holmes, Agatha Christie, Charlie Chan—but aren't we all also becoming increasing ly concerned about crime and its in sidious growth in our cities? It has been a hobby of mine to follow the ad vance in forensic science, much of it brought about by the parallel growth of sophistication in the fields of ana lytical chemistry and spectroscopy. Almost any good police department today can resolve cases with methods t h a t would amaze even Dr. Watson. T h e forensic scientist knows t h a t the crimincal always leaves his card. Any person entering or leaving the scene of a crime leaves a trace behind and carries something away with him. T h e forensic scientist must discover these traces and assess their signifiKased on 1978 Detroit Anachem Award Address
cance. A very common trace is the h u m a n fingerprint. T h e analytical chemist extends the idea of "finger printing" beyond human beings—to the identification of materials and their physical characteristics in a wide array of problems. T h e analogies are clear, and the approaches are guided by the same principles. In preparing for this Anachem Award Address I reviewed the file of examples t h a t formed the theme for "Super-Sleuth" over the years. In this process, it struck me t h a t as society has changed and as science advanced in even greater measure, our profes sion has adjusted and has made con tinuing contributions to both. As the problems of society and science have become increasingly complex, our methods have necessarily become more sophisticated and more respon sive. As the impact of future shock has accelerated the tempo of our lives, we have had to develop new ways to pro vide better answers more quickly. We can all be truly proud of our contribu tions to both science and society. I would like to review the path our pro fession has followed and the progress we have made in these "interesting times." I hope you will excuse me if most of my examples relate to molecu lar spectroscopy; after all, it is my own field. T h e same picture could be painted in any area of analytical chemistry.
The Post-War Period—Innovation's Heyday As World War II ended, a populace weary after a long depression and a global war, living under a new threat of nuclear holocaust, eagerly yearned
30 A · ANALYTICAL CHEMISTRY, VOL. 52, NO. 1, JANUARY 1980
for innovations in products and pro cesses which would improve their lives. T h e technology on which to base these advances had been generated under wartime pressures. T h e combi nation of eager consumers and avail able science made the 1950's the hey day of innovation in the United States. Yet, in retrospect, by today's standards the advances were relatively primitive. Analytical and spectroscopic meth ods were naive from our present view. Qualitative analysis was the order of the day. Industrial scientists were most frequently asked, " W h a t is i t ? " But a fledgling technique, infrared spectroscopy, was fast developing into a major industrial tool to provide the qualitative answer to just such ques tions. T h e infrared spectrum supplied the classic fingerprint of an unknown substance. Identifications never be fore possible in the same time frame or with the same ease became routine. New methods for obtaining the in frared spectrum of a wide variety of materials in various physical forms were rapidly introduced, including Nujol mulls and the KBr pellet tech nique. I remember very well the detective work required to solve this problem of qualitative analysis. In Figure 1 is shown the spectrum of a gasoline tank deposit obtained from a truck whose filter had been plugged by a solid ma terial. Of course, our fuel was suspect. We prepared the sample as a KBr pel let. T h e spectrum indicated the pres ence of cellulose and also exhibited bands between 7-7.5 μ and two sharp bands in the low frequency region. These bands were identified as being 0003-2700/79/0351-030A$01.00/0 © 1979 American Chemical Society
Report
LIQUID CHROMATOGRAPHY
INFIUREDSPECIHOSCOPY L INFRAREDs PECTROSCQPY Gas ChitHnatography/ Chromatography/ Mass Spectrometry Spectrometr characteristic of strontium nitrate. T h e solution was near at hand. We ex amined the truck to determine possi ble sources of contamination. A quick look showed t h a t the driver carried emergency flares in a sling directly above the tank. We speculated t h a t during a gasoline fill a flare had dropped into the tank. T h e binder containing cellulose from the filler and the paper had been dissolved by the gasoline. Strontium nitrate, the real clue in this case, is what makes flares burn bright red to alert passers-by to danger. We absolved our suspected fuel and pointed out the real villain: a careless fuel fill. In the field of analytical chemistry more complicated structural analyses were undertaken. A 1955 review in Scientific American highlights the structural determination of insulin— the first protein whose complete struc ture had been deduced. T h e task had required 10 years.
S p u t n i k — T h e S p a c e A g e and Miniaturization
T h e 1958 launching of Sputnik gave new impetus to U.S. science and engi neering. Few events in history have captured the public's imagination as did the ensuing space exploration. Much of the computerization and miniaturization we are applying today had its genesis in this program. Analytical and spectroscopic meth ods improved to keep pace with the continuing development of new prod ucts, such as stereospecific polymers and complex organometallic catalysts. No longer were we asked for simple qualitative answers. T h e new ques tions were, "How is it put together?" or " W h a t is its complete s t r u c t u r e ? " A new tool in the analyst's investi gation kit was added in the early 1960's when Block and Purcell won the Nobel prize for the development of nuclear magnetic resonance (NMR)
spectroscopy. T h e synergistic effect of combining IR and N M R added a new dimension to problem-solving. Con sider the example illustrated in Figure 2. We were asked to obtain the com plete composition of a commercial im pact modifier. An IR spectrum indi cated the material was a polymer of styrene and a methacrylate, but an unknown additional component was also present. Proton N M R spectrosco py confirmed this analysis, but the third ingredient was still a mystery. It required l 3 C N M R to identify t h a t both methylmethacrylate and butylmethacrylate were present in the poly mer in addition to the styrene. We could now quantitatively obtain the amounts of each component from the Ή N M R spectrum. All three analyti cal methods assisted in this analysis. Infrared gave the first rapid indication of the general class of polymer. Sol vent systems for N M R were then easi ly assessed. Carbon-13 N M R gave the
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ANALYTICAL CHEMISTRY, VOL. 52, NO. 1, JANUARY 1980 · 31 A
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Figure 2. Spectra of impact modifier, a) IR spectrum, KBr pellet; b) 1H NMR spectrum, indicating 39% styrene, 42% methylmethacrylate, and 18% butylmethacrylate; c) 13C NMR spectrum detailed composition qualitatively, and Ή N M R provided the quantita tive analysis. T h e analogy to law enforcement continued as forensic science made parallel advances. In 1962, J. Edgar Hoover published a case history in A N A L Y T I C A L C H E M I S T R Y (7)
de
scribing the use of various scientific and analytical resources of the FBI laboratories to determine the unusual cause of a plane crash. Instrumental analyses had an especially large im pact in the solution: A homemade bomb had been carried on board by a passenger! A new phenomenon, the Mossbauer effect, was creating excitment among analytical chemists, and the invention of the laser was about to give a rebirth to the field of Raman spectroscopy (2, 3). A review article in Scientific American in the early 1960's stated, " T h e author, an obstinate humanist and classicist, prefers to think that the triumph of physics is just the victory of Athena, the virgin goddess of intel lect, over most of her Olympian com panions. If only we do not throw away other human values, if we can save Aphrodite, the fertile goddess of beau ty and love, all should be well." T h e triumph of physics was also giving new dimensions to analytical chemistry. 32 A ·
T o illustrate the power of Raman spectroscopy in contributing to "real world" problems, Figure 3 shows the infrared and Raman spectra of cobalt molybdate on alumina. This impor t a n t catalyst for hydro-desulfurization is used commercially in supported form, but the usefulness of the in frared spectrum for catalyst structural information is severely limited by the interfering absorptions of the alumina support. On the other hand, the R a m a n spectrum is characteristic of the active catalyst with much struc tural information even to the low fre quency region. T h e striking capability of Raman spectroscopy to supply data on a very difficult sample is shown in Figure 4, the R a m a n spectrum of MoOv, a black powder. The Fall of Camelot—A New Era of Problems T h e election of Jack Kennedy as President of the U.S. and his vow to p u t a man on the moon gave further spirit to society in general and to science in particular. This age of eu phoria crashed to a close with his as sassination. Even in this sad moment of our history, spectroscopy found a role. Neutron activation analysis proved t h a t the controversial "single bullet" had hit both the President and
ANALYTICAL CHEMISTRY, VOL. 52, NO. 1, JANUARY
1980
Governor Connally. T h e methods used then were not conclusive, but recent reworking of that data using more ad vanced technology has supported the original efforts. Kennedy's death, followed by the additional assassinations of Robert Kennedy and Martin Luther King, Jr., and the escalation of the war in Viet nam opened an era of cynicism in the U.S. A new generation turned on all parts of the Establishment, including science, questioning the methods and values of the past. Protests were mounted against the war, inaction on civil rights and environmental pollu tion. Rachel Carson's A Silent Spring in 1962 led to Earth Day, 1970, sym bolizing a change in direction. T h e heritage of expansion in the past was a new philosophy for the future—and a new world of analytical problems. We had barely learned to detect parts per million (ppm) when the demand arose for parts per billion (ppb). Electro chemistry, atomic absorption, elegant liquid and gas chromatography sepa rations and classical "wet" chemistry methods were developed and pushed to new levels of sophistication in the intense effort to lower the analytical detection limits and improve sensitiv ities. T h e new and frequently asked questions of the analytical chemist be-
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Figure 3. Spectra of C0M0O4 on alumina, a) IR spectrum, Nujol mull; b) Raman spectrum, A r cm
came "When is zero, zero?" and "How little can you detect reproducibly?" Our "villains" were becoming increasingly more elusive and difficult to apprehend. In our laboratory, methods with detection limits in the ppm range were developed on a routine basis for monitoring hazardous chemicals within plants and in process effluents. In one example, a team of analytical chemists and spectroscopists was involved in obtaining FDA clearance on an acrylonitrile-based resin for food container use. (4) Detection limits of 0.05 ppb on nonvolatile residues from container extractions were achieved using infrared spectroscopy as the analytical tool. We had indeed come a long way. A renaissance in forensic science also occurred as a result of the use of multiple techniques to identify evidential items and the increased capability to analyze smaller samples and lower concentrations. Ray Williams reported in ANALYTICAL CHEMISTRY
in 1973 (5) t h a t the laser microprobe was capable of analyzing 10-250 μπι diameter areas of sample with a sensi tivity of 1 0 _ 1 ϋ to 1 0 - 1 1 gram absolute. This new era of analysis resulted in a major change in emphasis for those involved. As never before, the analyst must see himself or herself as a com plete problem solver using all the skills of a scientist rather than those of a narrow specialist. Complex analy ses of intractable materials at minute levels require the maximum power of combined separation methods with multiple analytical techniques. Gas chromatography combined with mass spectroscopy is an excellent example of the new direction the analytical chemist was taking. T h e determina tion of mechanisms of degradation of a complex chemical or the detection of the intermediate species in a catalytic reaction require a full knowledge of the basic chemistry and kinetics in volved. Today the involvement of ana lytical chemists in problems such as
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Figure 4. Raman spectrum of M o 0 2 , a black powder. 5145 À, 10 MW power, slits ~ 6 c m - 1 , a) Single scan; b) 150 scans, smoothed and baseline corrected 34 A · ANALYTICAL CHEMISTRY, VOL. 52, NO. 1, JANUARY 1980
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these is common. T h e modern analyti cal chemist no longer just answers questions, but rather solves problems or suggests solutions. Even the most mundane problems require a well-thought-out analytical plan and considerable ingenuity in de veloping a solution. We were asked to analyze a heavy black deposit t h a t was found around the seal of an intake valve removed from an automotive en gine. T h e vehicle was an aviation fueler at the Dayton airport, and it had experienced problems with severe valve sticking. There was the possibili ty t h a t the wrong oil had been added to the crankcase during the last servic ing—or was it sabotage? T h e analyti cal plan is shown in Figure 5. In accor dance with sound chemical principles, the sample was first separated into polar and nonpolar constituents. This simplifies the analysis of an obviously complex material allowing more defin itive conclusions to be reached. T h e separation scheme is a familiar one in
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ever, t h e bands marked with an " X " were t h e real culprit. They were iden tified as talc, ordinary magnesium sul fate. T h e analytical results could now be summarized. T h e used oil showed extensive fuel dilution, not uncommon in engines where excessive valve de posits have formed. Some additive de pletion from the oil was noted, con firming t h a t the additive had migrat ed into the deposit. Inorganic sulfates, carbonates, and phosphates, which are normal components of used oil, were seen. T h e identification of talc, how ever, indicated that there had been sabotage on the engine, accomplished by t h e introduction of talc into the en gine crankcase. T h e talc catalyzed the precipitation of the polymeric detergent-dispersant additive from the oil, forming, under the high temperature operating conditions of the engine, the severe deposit found on the valve. Since the gasoline contained no abnor malities, it was evident that the talc had been introduced through the crankcase rather than in the gasoline tank. Our detective work was over, and t h e true forensic workers took our efforts further. An analytical plan, backed by solid science, had obtained a conviction.
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Today the analyst has a t his or her disposal a vast number of techniques for solving problems and the ability to integrate these methods into a coher ent analytical plan. A popular feature in ANALYTICAL· CHEMISTRY, THE
I Octron Gasoline (IR. 0.1 mm)
Figure 5. Intake valve deposit: analytical flow chart
ANALYTICAL A P P R O A C H , effectively
A S T M methods for handling petrole um samples. T h e nonpolar constitu ents are pentane soluble; the polar materials will dissolve in acetonemethanol. Both the engine oil and the valve deposit were separated in this manner. All soluble and insoluble fractions were examined by IR. T h e gasoline from the fueler tank was also
examined in t h e infrared. T h e engine oil was ashed and a qualitative test for sulfate was made. Figure 6 shows the IR spectrum of the valve deposit with the most signif icant "clues" indicated. T h e circled bands were recognized as the additive from t h e motor oil which had been specified for use in this engine. How
documents examples of this responsi bility and its impact in problem-solv ing. Without a well-conceived plan, the power of the analyst is dissipated by wasteful tests of doubtful value. Where Do We Stand Today? It would be easy for analytical chemists a n d spectroscopists to rest on their laurels and on a brilliant rec-
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Figure 6. Intake valve deposit: IR spectrum 36 A · ANALYTICAL CHEMISTRY, VOL. 52, NO. 1, JANUARY 1980
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How sample injectors affect LC accuracy. Free report tells how to improve precision by choice of injection technique. This 8-page Rheodyne technical note reports the results of experi ments using different sample loading techniques — and discusses the distinctive characteristics of eight popular injectors. Among the questions answered are: • What analytical precision can be expected in H PLC? • Which injection techniques provide the highest reproducibility? • What role is played by varia tions in flow rate, solvent composition and temperature? • How can volumetric errors of injectors be avoided 9 The report covers sample injectors from various manufacturers It contains practical advice on the use of injectors for the novice - as well as forthe experienced chromatographer.
ord of responding to ever-changing and increasingly difficult demands. T h e use of powerful combined-tech nique analyses, well-thought-out ana lytical planning, an emphasis on the use of sound basic chemical principles, and the accepted concept of an analyst as a problem solver have all led us to what seems to be quite a lofty plateau. Certainly we are deluding ourselves if we adopt t h a t attitude. There is still very much to be done. T h e t r u t h was probably best expressed by the anony mous analytical chemist who said, "We have not succeeded in answering all your problems. T h e answers we have found only serve to raise a whole set of new questions. In some ways we feel we are as confused as ever, but we believe t h a t we are confused on a higher level and about more important things." T h e world around us is not getting simpler. Societies are becom ing ever more interdependent. Actions of one group produce effects on others. It will be increasingly important to trace these impacts and to assist in minimizing them. I believe the future will be more demanding, in ways t h a t are difficult to forecast. The Future—Challenge to a Proud Profession T h e problems of society are not dis appearing. T h e contributions of both analytical chemists and forensic scien tists will be required to grow. For ex ample, analytical chemists will be asked to trace the metabolism of toxic materials in humans, and forensic sci entists will use this knowledge to un ravel narcotic and poisoning cases. T h e trend will be toward lower level analyses and the study of reaction mechanisms in their reacting environ ments. T h e ultimate in quantitative detec tion, single atom analysis, is already a reality and will become a more com mon achievement. In situ methods for dynamic studies of systems and molecules will be de manded by our colleagues in the cata lytic, biochemical and organic sci ences. These methods will probe even
To get your free copy promptly, contact Rheodyne. Inc.. 2809 Tenth St., Berkeley. Calif. 94710. Phone (415)548-5374.
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References (1) Hoover, J. E., Anal. Chem., 1962, 34(12), 23A-32A. (2) Grasselli, J. G.; Hazle, Μ. Α.; Wolfram, L. E. In "Molecular Spectroscopy"; West, Α., Ed.; Heyden and Son: New York, 1977. (3) Grasselli, J. G.; Hazle, M. A. S.; Mooney, J. R.; Mehicic, M. Proc. Colloq. Spectrosc, 21st, and Int. Conf. Atomic Spectrosc, Heyden and Son: New York, in press. (4) Gaylor, V. F., Anal. Chem., 1974, 46(11), 897A-900A. (ô) Williams, R. W., Anal, Chem., 1973, 4.5(13), 1076A-1089A.
Jeanette G. Grasselli obtained her B.S. degree in chemistry at Ohio University, an M.S. at Case Western Reserve University, and a Doctor of Science degree from Ohio University. After graduation, she joined the Research Department of The Standard Oil Co. (Ohio) where she is currently Analytical Coordinator and Supervisor of the Molecular Spectroscopy and Laser Research Sections.
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38 A ·
further into structures in the ground and excited states. Multiphoton, pi cosecond and time-resolved spectros copy must be advanced to capture bet ter views of short-lived reaction inter mediates and to understand the reac tion pathways. We have only begun to see the ad vances made possible by automation, computerization and miniaturization. This burgeoning technology will im pact analytical chemistry and society in equal measure. We will be asked to delve ever more deeply into the fundamental structure and understanding of molecules. Laser-enhanced ionization and fluo rescence, E X A F S , electron energy loss spectroscopy, the various surface spec troscopies, and ion cyclotron reso nance (to mention but a few) will see spectacular gains. It will never be possible for us to de tect and "convict" all the chemical or societal "villains," but I am sure t h a t we will continually improve our meth ods and our success ratio. Ours is a proud profession. It has proven its ability to serve society and meet the demands of our fellow scien tists. Yet I must agree with industrial ist Charles Kettering who once ob served that, "My interest is in the fu ture because I am going to spend the rest of my life there." This eager an ticipation of what is to come cannot detract from the satisfaction of having lived also in the "interesting" times of the past. I am very happy to have been a part of these efforts.
1980
