REPORT
The EvolutionofCommercial IR Spectrometers and the People Who Made It Happen Paul A. Wilks, Jr. General Analysis Corporation 140 Water St., Box 528 South Norwalk, CT 06856-0528
After three decades of study in uni versity physics l a b o r a t o r i e s , t h e value of IR spectroscopy to the or ganic chemist began to become ap parent in the late 1930s. Norman Wright a t Dow a n d R. Bowling Barnes, first at Princeton and later at American Cyanamid, built IR spectrometers and d e m o n s t r a t e d their value for quantitative and qual itative chemical analyses. However, it took the impetus of World War II and the synthetic rubber program to bring about the introduction of com mercial IR spectrometers. Among B a r n e s ' e a r l y s t u d e n t s were Van Zandt Williams and Robert Brattain, both of whom later had a profound effect on the commercial ization of IR spectroscopy. Williams followed Barnes to Cyanamid and later moved to Perkin Elmer. Brat tain joined the Shell Development Company and was instrumental in the early stages of the Beckman IR program. Having participated in the early days of Perkin Elmer's IR program, I would like to add to accounts of the development of commercial IR spec troscopy by including personal remi niscences of the people involved and the early problems that had to be solved before this most useful of ana lytical methods could be made gener ally available. I apologize to my friends at Beckman and Baird that this presentation of events from that era is almost totally from the Perkin Elmer perspective, but that is how I lived it. I would refer those inter ested in the parallel development of the IR program at Beckman to "His 0003-2700/92/0364-833A/$03.00/0 © 1992 American Chemical Society
tory of Spectrophotometry at Beck man Instruments, Inc." by Beckman, Gallaway, Kaye, and Ulrich (Anal. Chem. 1977, 49, 280 A).
Early design and development The P e r k i n - E l m e r Corporation, when John U. White and I joined it in the summer of 1944, occupied a small, modern plant in Glenbrook, CT (a suburb of Stamford) and had a p p r o x i m a t e l y 60 employees. I t s principal business was manufactur ing optics for tank sights and aerial cameras for the war effort. Founded by Richard S. Perkin and Charles W. Elmer, who shared a common hobby of amateur astronomy, the company's original purpose was to provide a source for the design and fabrication of large, specialized optics for astron omy, which at the time were avail able only in Europe. It was natural that Barnes and his co-workers at Cyanamid would turn to neighboring Perkin Elmer for the u n u s u a l optical elements they needed for their spectrometers. Not only did Perkin Elmer have two ex ceptionally able optical designers in Lloyd McCarthy and Richard Ken-
aird, but—even more important— Perkin Elmer's chief optician was Halley Mogey, a gifted craftsman who seemed able to devise methods to make any kind of optical element, no matter how complex. (Mogey, who was born in 1910, and whose father was an astronomer, was named for Halley's comet.) At Cyanamid, a large IR spectrom eter had been built before World War II. This instrument was about the size of a desk, and it had a glass cover over which was an aluminum sheet. The laboratory had many visi tors, and Barnes would remove the aluminum sheet to show the optics while the instrument continued to run. Many visitors, used to UV-vis i n s t r u m e n t s , were surprised t h a t this demonstration did not upset the s p e c t r o m e t e r ' s p e r f o r m a n c e . The thick glass plate kept out the IR ra diation. The instrument had a large rock salt prism with 10 χ 15 cm faces. To minimize the chance of fogging when the instrument was not being used, the prism was removed, stored in a desiccator, and replaced with a piece of wood of equal size. One visitor, who should have known better, re marked, "I didn't know t h a t wood transmitted IR [radiation]." Cyanamid developed a prototype single-beam spectrometer (Figure 1) and sent it to Rubber Reserve. Then they built four more. One was kept at Cyanamid, one was sent to Norman Coggeshall at Gulf Research Labora tories in Pittsburgh, and another was sent to Raymond Fuoss at General Electric for studying silicones. The fourth i n s t r u m e n t went to Perkin Elmer to be used as a prototype for future designs. I believe that it now resides in Perkin Elmer's museum of instruments in Germany. The Cyanamid instrument design
ANALYTICAL CHEMISTRY, VOL. 64, NO. 17, SEPTEMBER 1, 1992 · 833 A
REPORT (because of its high aperture) required an off-axis paraboloid as a collimator rather than the usual sphere. Another aspheric mirror (this time an ellipsoid) was required to focus energy on the detector. Mogey fabricated the off-axis paraboloid by polishing a large parabolic surface and then biscuit-cutting from the surface of the paraboloid discs that were the correct number of degrees off-axis. The ellipsoid was roughed out on a curve generator and polished by means of a small button lap. According to Bob McDonald, then an analytical chemist at Cyanamid, the paraboloid so improved the resolution of the small instrument that it out-performed the larger spectrometer. McDonald received the paraboloid on the day before a holiday, installed it on his day off, and had spectra to show his surprised coworkers when they returned after their holiday. The third critical element was the rock salt prism. (Early spectrometer makers had been forced to make their prisms from natural rock salt, but by the time Perkin Elmer started its program, Harshaw Chemicals was growing large sodium chloride crystals.) Water is usually used as a lubricant in optical polishing, but because sodium chloride is soluble, early opticians tried to use alcohol. Because of its volatility, alcohol evaporates rapidly and causes scratching. Mogey quickly realized that water saturated with sodium chloride would dissolve no more salt, so he polished the prism surfaces using salt water as his lubricant. He taught me how to buff the fogged
surface of a salt prism—usually fogged with my own breath as I aligned the optics of a spectrometer—by stretching a polishing cloth over an optical flat, breathing on it to moisten it, rubbing it on the skin of my arm to pick up salt, and then gently rubbing the prism face to return its shine without changing the optical figure. Detectors were another problem component. The most sensitive detector at the time was the vacuum thermocouple. In that early period, we had to follow a rather complex procedure to procure our finished detector units. The best thermocouple units were those made by a small company in Boston, located near Faneuil Hall. Because the thermocouples were too delicate to ship, I drove to Boston each month to pick up our supply. We mounted each thermocouple in a metal holder and sealed on it a salt window t h a t I had laboriously cleaved from a salt block. We then waxed on a glass getter bulb filled with activated carbon. Finally, because Perkin Elmer did not have an evacuation system, we took the assemblies over to Cyanamid for pumping out. We usually started with 30 elements and hoped that we would end up with 10 good ones for our month's production. The three principals of the Boston thermocouple company were Barney O'Keefe, who eventually became head of EG&G; Donald Hornig, who later became president of Brown University; and Walter Hargreaves, founder of the Optovac Company, which grows IR crystals.
My first job at Perkin Elmer was assembling and aligning the Model 12A IR spectrometer. Richard Perkin told me he expected to produce 25 instruments, and then the market would be saturated. By the time I had finished and shipped the twentyfifth instrument, our backlog of orders had reached 65! These early models were dc instruments that would operate only in humidity- and temperature-controlled atmospheres. Because central air conditioning was still a few years away, the first industrial spectroscopists tended to barricade themselves in their specially controlled rooms, letting no one else in lest the spectrum being recorded be ruined. As a result, spectroscopists earned the reputation of being recluses who spoke only to other spectroscopists. The Perkin Elmer optical shop was operated at a constant temperature, so we did our final optical alignment there using a galvanometer with lamp and scale. If we could see the C0 2 doublet when we hand-scanned through it, the optical performance was considered satisfactory. Later, as the quality of the optics improved, we used more closely spaced bands in the water vapor region. One of the first accessories for the Model 12 was a device that attempted to flatten out the 100% transmission line. It consisted of a spiral cam that had been handcarved by John White and was fastened to the wavelength screw (Figure 2). A string was wrapped around the barrel of the slit micrometer and attached to the cam. When the wavelength screw turned, the slits were opened to counteract the fall-off in energy. New developments broaden IR use
Figure 1. The Cyanamid single-beam IR spectrometer prototype. 834 A · ANALYTICAL CHEMISTRY, VOL. 64, NO. 17, SEPTEMBER 1, 1992
Three developments in the late 1940s had a profound effect on Perkin Elmer's IR program and ultimately on IR spectroscopy in general. The first occurred at General Motors Research Laboratories, where Max Liston developed a breaker-type dc amplifier. This amplifier eliminated the galvanometer and made it possible to feed the amplified thermocouple signal directly to a strip chart recorder. Liston, together with Charles Reeder, created a fast thermocouple that permitted the IR signal to be chopped at 13 cycles, a development that freed the IR spectroscopist from having to cope with thermal drift. (The spectroscopist still would not give up his air-conditioned room, however, contending that he needed
it to protect his hygroscopic cell windows.) The third, and probably most important, development came from Norman Wright's group at Dow: the double-beam optical system t h a t made it possible to record IR spectra directly as percent transmission—a process that eliminated the effects of atmospheric absorption and the blackbody emission curve. Richard Perkin had the ability to convince practically anyone he approached to join Perkin Elmer. He brought Van Zandt Williams from Cyanamid to head the IR group, and Max Liston also became part of the team. With this group and one other individual, Williams started the Perkin Elmer double-beam development program. White did the optical design; Liston the electronics; and a young designer from Yale, Vincent Coates, did the mechanical design. The net result was the Model 21 double-beam IR spectrometer. One of the most successful analytical instruments ever introduced, it helped catapult Perkin Elmer from a relatively obscure s m a l l i n s t r u m e n t manufacturer to a major electrooptics corporation and Fortune 500 member. Those who are familiar with the Model 12 and the Model 21 will recall that the energy flows from left to right in the Model 12 and is reversed in the Model 21. The shift in direction came about in this fashion: John White was intrigued by the fact that
S
pectroscopists earned the reputation of being recluses who spoke only to other spectroscopists.
•••
I seemed to be the only one who could easily align the slits in the Model 12. While watching me work on an instrument one day, he suddenly exclaimed, "You're left-handed, aren't you?" With that observation, he immediately went back to his drawing board and reversed the direction of the optical design of the Model 21. By the time the Model 21 went into production, I had moved on to other duties, and I did not have to assemble the right-handed instrument. Legend has it that Van Williams and John White personally took the
Model 21 prototype to Grand Central Station in New York City, where they procured a lower berth for the instrument for the overnight trip to Detroit. Williams and White presented the Model 21 at the 1950 Optical Society of America meeting in Detroit. Although Williams passed away at the height of his career, Liston and Coates now manage highly successful companies that they each founded, and John White is a widely known independent consultant most famous for designing the White multipass gas cell. A landmark session at Ohio State In the early days, before the Pittsburgh Conference assumed its dominance, papers on new developments in IR i n s t r u m e n t a t i o n were p r e sented at the Columbus Symposium (more properly known as the Ohio S t a t e S y m p o s i u m on M o l e c u l a r Structure and Spectroscopy). One memorable session was on Friday of the 1949 meeting, over which John Beach presided. R o b e r t B r a t t a i n opened the session with an excellent summary of the requirements of IR i n s t r u m e n t a t i o n from t h e u s e r ' s standpoint. Howard Cary then compared the two newly developed methods of obtaining a flat I0 curve: memory s t a n d a r d i z a t i o n a n d doublebeam operation. These two survey p a p e r s were followed by Roland Hawes' presentation of the Beckman IR-3 memory spectrometer and John White's description of the Model 21. In the afternoon similar introductory papers were presented on Baird's new double-beam instrument, Frank Rugg's homemade instrument, and Marcel Golay's multislit spectrometer. Closing out the session were papers on the new Luft and Baird nondispersive IR (NDIR) gas analyzers. Probably at no other session were so many significant advances in IR i n s t r u m e n t a t i o n i n t r o d u c e d . Although the IR-3 was not a successful i n s t r u m e n t from a c o m m e r c i a l standpoint (mainly because it was far ahead of its time), it did presage the memory system used in present-day FT-IR instruments. Competing for the IR market
Figure 2. This Model 12A spectrometer shows two John White innovations: the spiral cam for the /0 flattener on the wavelength control (right) and the first folded-path "White" gas cell in the sample compartment (left).
During the 1940s and 1950s, intense competition developed among Baird, Beckman, and Perkin Elmer for dominance in the IR market. As the principal use of IR spectroscopy leaned more and more toward qualitative determinations and structural analysis, resolution became the most imp o r t a n t c r i t e r i o n of i n s t r u m e n t excellence. Baird and Beckman
ANALYTICAL CHEMISTRY, VOL. 64, NO. 17, SEPTEMBER 1, 1992 · 835 A
REPORT / number. Perkin Elmer ultimately prevailed because of the indisputable fact that a lower/number resulted in a higher energy throughput. Because of t h e well-known trade-off rules, t h a t higher energy could be used to increase speed, signal-to-noise ratio, resolution, or a combination of all three. All early instruments were prism models. Sodium chloride (rock salt) was the basic crystal used because it nicely covered the mid-IR fundamen-
achieved higher resolution by means of large-diameter optics and long fo cal lengths, which resulted in rather high / numbers. On the other hand, Perkin Elmer, with its skill at pro ducing aspheric optics, was able to attain high resolution with much shorter focal lengths and hence lower /-number optics. Heated a r g u m e n t s occurred d i rectly and in the literature between Beckman a n d Perkin Elmer engi neers about t h e importance of t h e
Ft Ο D U C T I V Ε ÙK*9 Γ-1R Ι * Λ Ί = Ι · 3 : ? ± % ί · 1 : V « Λ g l : M * i 1 =Ι»3;?Λ% ί Ο : ¥ * * β ( ; « J H > ' < i l « J : T t \ i f l
.0006
J J
.0002
-.0002 -.0006
4000
3400
2800
2200
1600
; V « 3k 0 1 ; a ^ i l = M ; 7 · \ ί Ο : k ' « sk £11 :MM WX --1·1 The MB Series offer you the parameters for productive FT-IR : Performance*: sensitivity to 50μΑ p-p, baseline accuracy of better than 300μΑ and linearity up to 3A. Constant performance results in analytical reliability! Ease-of-use : fast accurate sample placement, permanently aligned optics and easy software. Minimal training and skill are required for basic operation. Versatility : 3 choices of software; Basic, Advanced and Turnkey. Variable resolution up to 1 cm' 1 and choice of detectors including PAS. Reliability : No down time in 18 months of use for over 90% of owners. Consider the Bomem MB Series. Superior FT-IR at slightly higher price. * On open beam spectrum when measured at 4 cm ' resolution over 2,1002,000 cm"' with 20 minutes coadding using the standard DTGS detector.
Models & Spectral
:TL\
1000 400 CO ; V « sk β I :K3
Compare with other models: BOMEM Digilab MB100 FTS-7
Nicole! 205
PerklnElmer 16PC
Permanent alignment . Yes Exchangeable sample compartment Yes 4 port optical design Yes; Operate in any '. orientation T~"TKn Fast detector interchange Yes Small footprint ; Yes PC-AT computer Yes Side port Yes Direct acquisition in LabCalc Yes Microscope interface Yes Wide spectral range beamsplittertechnology Optional Microbeam compartment Optional Sub-second DSP processing Optional
Ranges
MB102:5,000 cm-'to 210 cm-1 MB155:14,000 cm-1 to 450 cm-1 MB100:6,000 cm"1 to 350 cm-' MB160:15,000 cm-1 to 3,700 cm-1
BOMEM Hartmann & Braun
See us at the FACSS Meeting Booth 2 0 2
Bomem loc./Hartmann & Braun 450 Saint- Jean-Baptiste Ave Qoebec. Quebec Canada G2E5S5 Tel·: (418) 877-2944 North America : 1 800 888FTIR
CIRCLE 22 ON READER SERVICE CARD 836 A · ANALYTICAL CHEMISTRY, VOL. 64, NO. 17, SEPTEMBER 1 , 1992
tal region out to 15 μπι (we called it the rock salt region). Lithium fluo ride a n d calcium fluoride p r i s m s were used to enhance resolution in the l - 9 - μ π ι region, a n d potassium bromide (and later cesium bromide) extended the useful range to 25 μπι and 40 μπι, respectively. Walsh's double-pass optical design doubled the resolution of the prism monochromator and was incorporated into the Perkin Elmer Model 112. While t h e variety of prisms a n d optical configurations helped to in crease t h e qualitative power of the early IR instruments, much atten tion was also given to enhancing the quantitative precision. The original thrust for t h e commercial develop m e n t of IR i n s t r u m e n t a t i o n came during World War II as a result of the synthetic rubber program. IR spectroscopy was t h e only method available that could follow quantita tively t h e styrene-butadiene reac tion that produced the natural rub ber substitute. Single-beam instruments had proven to be capable of making pre cise quantitative measurements, but double-beam, optical-null i n s t r u ments were much less accurate be cause of their dependence on the op tical wedge to precisely balance t h e two beams, and the wedge became inaccurate a t t h e upper a n d lower 10% of its range. Beckman instru ments were operable in either singleor double-beam modes to provide both quantitative and qualitative r e sults. Perkin Elmer tinkered with the optical wedge a n d also i n t r o duced Abe Savitzky's ratio-recording instrument, the Model 13, which was aimed a t better quantitative perfor mance. This research w a s all for nought, however, for during the mid1950s GC made its appearance and totally eclipsed IR spectroscopy as a quantitative tool.
Expanding markets IR applications spread rapidly dur ing the 1950s. One example of how IR spectroscopy penetrated a com pletely new industry resulted from a visit to Perkin Elmer by a salesman for a supplier of essential oils. The salesman brought in a competitor's sample that was being offered a t half his company's price. H a r r y H a u s dorff, Perkin Elmer's IR applications specialist, r a n a spectrum of t h e sample a n d discovered that t h e oil had been cut 3:1 with an odorless sol vent—a deception that was readily detectable with IR spectroscopy but undetectable to t h e h u m a n nose, which is wonderful a t sensing odor
differences but very poor at quantitative analysis. Hausdorff became so intrigued by the power of IR spectroscopy that he made a thorough study of the materials used in the perfume industry. He presented the results at a meeting of the Society of Cosmetic Chemists. Helena Rubenstein remarked after his talk that she hoped that "this instrument would be banned from use by perfumers or all our trade secrets will be exposed." Her views did not prevail, however, for in the next two years Perkin Elmer sold 60 Model 21 spectrometers to the perfume and essential oil industries. Toward the end of the decade, after much experimentation, methods for replicating gratings were finally developed. As a result, resolution increased by an order of magnitude, and the era of prism IR spectrometers rapidly came to a close. In the ensuing 20 years first Baird and then Beckman withdrew from the commercial IR market, and Perkin Elmer was left in almost total domination of the IR field—that is, until the introduction of the Fourier transform interferometers, but that is not my story to tell. When I left
Perkin Elmer in 1957, Van Williams and Abe Savitzsky were investigating the interferometers being developed in Europe, and I recall Williams telling me that he thought this was the future of IR spectroscopy. Why it took Perkin Elmer almost 30 years to join the FT-IR bandwagon remains a mystery to me. In the summer of 1954 I was invited to visit the Du Pont research center in Wilmington, DE, to discuss Du Pont's future requirements for analytical instrumentation. At lunch, I was informed that where I was sitting in the Du Pont Country Clubhouse would be the center of the expanded Experimental Station. "We've already started construction of nine new holes for the golf course to make up for the nine we must take for the expansion program," I was told. I was also informed t h a t the planners of the new Experimental Station were thinking of installing several "analytical alcoves" in each new building. Each alcove would contain, among other things, an IR spectrometer. "But," said my hosts, "the Model 21 is too expensive and the Model 12 is too difficult to use. What we really need is a spectrometer that
the bench chemist can use routinely at a price we can afford." On the train back to Stamford, I mulled over the problem of producing a low-cost i n s t r u m e n t , and it occurred to me that much of the cost of the Model 21 was in its versatility. If the complicated slit program and w a v e l e n g t h speed c o n t r o l s w e r e eliminated, an instrument with fixed parameters could be constructed at a much lower cost. T h e idea of a low-cost "bench chemist's" i n s t r u m e n t took a long time to gain acceptance at Perkin Elmer; there were fears that it would "kill the golden goose" (the Model 21). When our industrial espionage procured information that Beckman h a d hired none other t h a n J o h n White to design a low-cost version of the IR-4 spectrometer, all restraints were eliminated. When our Model 137 was introduced at the 1957 Pittsburgh Conference, it gained immediate acceptance. Sales of the Model 21 continued to grow steadily, and the new low-cost instrument removed IR analysis from the exclusive realm of the specialist and made it available to a completely new m a r k e t . The Model 137 development program was
Put your samples on a salt-free diet Tired of cleaning salt plates? Try quick and easy 3M Disposable IR Cards. These disposable sample cards fit major FTIR spectrometers and reduce time-consuming sample preparation. Samples are applied directly onto the microporous, polyethylene substrate, which quickly absorbs and holds the analyte. Since the cards are disposable, the risk of cross-contamination is eliminated. Likewise, no more sample clean-up translates into savings in both time and supplies. 3M Disposable IR Cards are non-hygroscopic and require no special storage or handling. They work most favorably with organic liquids, samples soluble in organic solvents, and semisolids or pastes. The cards are especially effective with water-containing samples.
To order 3M Disposable IR Cards, contact either Fisher Scientific or VWR Scientific. 3M Disposable Products Division 3M Center St. Paul, MN 55144-1000
3M Disposable IR Cards (25-pack)
CIRCLE 74 ON READER SERVICE CARD
3M
ANALYTICAL CHEMISTRY, VOL. 64, NO. 17, SEPTEMBER 1, 1992 · 837 A
Sample preparation for XRF-AA-ICP-CHEM.
Ml
ΪΜΠΗ with
Claisse Fluxes
(Borates and Phosphates) V J e t a new perspective on analysis and better results. The CLAISSE FLUXES have exceptional qualities due to their PURITY and COARSE texture. Claisse Fluxes are Tip-Top.
FEATURES • free-flowing crystals • low surface area • high density • fused, not mixed • popular and special compositions CONSEQUENT ADVANTAGES • no loss from static electricity • no loss by splattering or foaming on heating • very low water absorption I no uncertainty on quantity weighed • no segregation in containers • FREE SAMPLE upon request
REPORT managed by John Atwood, who intro duced new manufacturing methods to Perkin Elmer by replacing costly m a c h i n i n g procedures w i t h toolformed sheet metal parts, a change that reduced the cost for some parts by an order of magnitude. The Model 21 and its succeeding models were manufactured for an other 10 years. The Model 137, how ever, was the genesis of an entire family of IR instruments t h a t still appear in the Perkin Elmer catalog. Two additional anecdotes from my reminiscences will be of interest in light of latter-day developments. As a Perkin Elmer salesman, I recall a sales visit I made to Karl Norris at the U.S. Department of Agriculture laboratory in Beltsville, MD. Norris said to me, "I'd love to have a Model 21 because I think my work on grain analysis would be better carried out in the mid-IR region. But my budget won't allow it, so I m u s t use the near-IR region, which is available in my Cary UV spectrophotometer." If Norris could have afforded a Model 21, the great potential of analyses u s i n g t h e n e a r - I R region m i g h t never have been discovered! The second a n e c d o t e c o n c e r n s Howard Cary. There was a mutual respect between Perkin Elmer and Cary's company, Applied Physics Laboratories. Richard Perkin h a d opened merger talks with Cary, and Cary seemed quite receptive (proba bly, as I was to learn later, because a rapidly growing company cannot generate sufficient cash to sustain its growth.) Perkin asked me to make myself available to Cary to answer his questions about Perkin Elmer, and I made several trips to the west coast to visit him. The negotiations were all for naught, however, be cause of a r a t h e r u n d e r s t a n d a b l e problem: Neither Howard Cary nor Van Williams could see himself re porting to the other.
Van Zandt Williams, with his abiding faith in the future of IR spectroscopy, helped guide Perkin Elmer to its dominant position in the field. the UV wavelength region," he said. He t h e n s p r e a d h i s h a n d s wide apart, saying, "and this is the IR re gion. It is much broader and contains much more useful information." Now that we think in terms of frequency rather than wavelength, Williams' il lustration would have to be some what different. Williams was amazed at the rapid ity of developments in commercial IR instrumentation during the 1950s. He often remarked that someday a sample could be placed in a spec trometer, and the instrument would print out the structural diagram of the molecule and the name of the compound. With the wonderful search programs now available and our increasing knowledge of the rela tionship between molecular structure and absorption frequencies, it would seem t h a t his prediction has j u s t about come to pass.
Van Williams' vision realized
For world-wide sales, address of local agents and service information please call or write to: corporation scientifique claisse inc.
2522. chemin Sainte-Foy Samte-Foy (Québec) Canada G1V 1T5 Tel: 1418) 656-6453 Fax: (418) 656-1169 Telex: 051-31731
The First and Finest in Fusion.
Those were the glory days of disper sive IR spectroscopy. My fondest rec ollections of the early instrument pi oneers are of Van Zandt Williams, for whom I worked for 12 years and who remained a close friend after we both left Perkin Elmer (see photo above). Williams was totally committed to the advancement of IR spectroscopy to the exclusion of other spectral re gions. At a stockholders' meeting, when someone asked him why Per kin Elmer had not brought out a UV spectrophotometer, he held up his hand with his thumb and forefinger spaced about an inch apart. "This is
CIRCLE 20 ON READER SERVICE CARD
838 A · ANALYTICAL CHEMISTRY, VOL. 64, NO. 17, SEPTEMBER 1, 1992
Paul A. Wilks, Jr., president of General Analysis Corporation, received his B.S. degree in engineering from Harvard Col lege. He joined Perkin Elmer in 1944 and continued there until 1957. He formed the Connecticut Instrument Corporation with Charles W. Warren in 1958. In 1962 he founded Wilks Scientific Corporation, which became part of the Foxboro Com pany in 1977. At General Analysis Corpo ration, which he founded in 1979, Wilks has developed IR process analyzers and the Macro Lightpipe gas cell.
