50
YEARS ANALYTICAL CHEMISTRY
It is a pleasure to appear at this symposium in honor of Dr. Lawrence T. Hallet, editor emeritus of ANALYTICAL C H E M I S T R Y . The pleasure is somewhat tempered by the difficulty of reviewing the major advances by analytical chemists during the 1960's and especially the influence the JOURNAL ANALYTICAL C H E M I S T R Y had
Analytical Chemistry: the Journal and the science, the 1960's J. D. Winefordner Department of Chemistry University of Florida Gainesville, Fla. 32611
on the directions that research took during the time period 1960-1969.1 am sure any decade is, or would be considered, exciting, but I am especially fond of the 1960's since this is the time period when I personally discarded my scientific crutches and learned to walk on my own, sometimes carefully and sometimes a little recklessly. It should, therefore, be obvious to all that I should feel the 1960's were the years of great strides in atomic spectrometry. Most of these developments were initially, or at least immediately after their inception, published in ANALYTICAL C H E M I S T R Y (Table I). However, the 1960's were years of rapid and extensive analytical developments in several areas besides atomic spectrometry, namely, liquid chromatography, especially the instrumentation; gas chromatography, especially the applications to analytical and physical systems; thermometric methods, especially instrumentation; reaction rate techniques; phosphorescence spectrometry; ion-selective electrodes; modern electrochemical methods; analytical mass spectrometry; activation analysis; and X-ray fluorescence spectrometry. Prior to discussing areas where great activity by analytical chemists took place in the 1960's, I must admit that this review will be quite biased by my interests, my enthusiasms, and my ignorances. However, I have made an attempt to evaluate as fairly as possible the work in analytical chemistry (the area) and in ANALYTICAL C H E M ISTRY (the J O U R N A L ) . T O facilitate this review, I will divide the talk into three parts based upon fundamental areas of analytical chemistry and based upon activity by analytical chemists within the 1960's. The latter subdivision is performed to indicate fundamental areas where analytical chemists (High Activity) performed the major portion of the innovative work on principles, instrumentation, methodologies, and applications during the 1960's; where analytical chemists (Moderate Activity) performed considerable work on methodologies and applications; and where analytical chemists (Low to No Activity) per-
1302 A · ANALYTICAL CHEMISTRY, VOL. 50, NO. 14, DECEMBER 1978
formed very minimal studies. It should be stressed that in most areas of high activity during the 1960's, the 1950's and the 1940's were times of low or no activity by analytical chemists in those areas. However, those earlier years involved active work by physicists and often physical chemists. Generally, although I wish it were different, analytical chemical research follows the work of more fundamental workers. This trend certainly was changing in the 1960's with analytical chemists becoming involved much more with fundamental aspects of measurements. The areas of low or no activity in the 1960's concern those research techniques primarily developed by physicists and/or physical chemists. Such areas were generally characterized by a lack of commercial instrumentation, a necessity of expensive modular components which had to be built into an integral system that might have little analytical use. Because of the expense of the latter systems, oftentimes the lack of any unified theory, and the difficulty of obtaining research funds for such "untested" techniques, few analytical chemists had the opportunity to be involved in the developmental stages. Fortunately, the times were changing (see the 1970's). The major instrumental advances affecting analytical chemistry in the 1960's were concerned with: the introduction of semiconductive devices to replace their transistor and vacuum tube counterparts; the commercial availability of minicomputers (microcomputers and microprocessors came in the 1970's); and the initial commercial availability of CW and pulsed lasers. Semiconductive devices and minicomputers revolutionized electronic measurement systems in all areas of measurement, including signal processing and instrument control. Lasers were just beginning to be utilized in the 1960's for analytical methods and by analytical chemists, e.g., in the areas of conventional Raman spectrometry and the laser microprobe. However, the great influence of lasers in analytical chemistry was not recorded until the 1970's. Certainly, thé greatest single factor influencing the use of measurement systems for analytical chemistry was the development of modular electronic instrumentation by H. V. Malmstadt and C. G. Enke and the commercial production by Heath Co. and the publication of two Electronics for Scientists books (one analog and one digital) by
0003-2700/78/A350-1302S01.00/0 © 1978 American Chemical Society
50
YEARS M a l m s t a d t , Enke, et al., in t h e 1960's. T h e most significant advances by ana lytical chemists in t h e 1960's were a direct result of analytical chemists probing t h e fundamental aspects of analytical measurements rather t h a n awaiting developments by physicists and physical chemists. T h i s approach had been t h e one used by electroanalytical chemists for years b u t did not really " r u b off" onto other types of an alytical chemists until t h e 1960's.
High Activity Areas in the 1960's Atomic S p e c t r o m e t r y . More pa pers were written on atomic absorp tion spectrometry (AAS) t h a n perhaps all other areas of atomic spectrometry combined. However, most of t h e pa pers published were involved in modi fication of methodologies, improved or new applications, a n d to a lesser ex tent, with new a n d novel i n s t r u m e n t a tion. T h e most novel research projects involved t h e use of t h e acetylene-ni trous oxide flame and t h e graphite furnaces. T h e hot, reducing acetylenenitrous oxide flame allowed workers to d e t e r m i n e elements, such as Mo, V, T i , Al, Be, a n d other strong monox ide formers, t h a t were difficult t o de termine in t h e acetylene-air flame. T h e development of t h e a c e t y l e n e nitrous oxide flame as an analytical flame (by J. B. Willis) was certainly the major development in AAS in t h e 1960's. P e r h a p s t h e most active area in AAS involved furnace atomizers for m e a s u r e m e n t of small a m o u n t s of samples. A great flurry of research on furnace atomizer types (B. V. L'vov, H. Massman, R. Woodriff, etc.), ex perimental conditions, a n d uses re sulted especially as commercial instru m e n t a t i o n became available. T h e ini tial flurry waned later, especially dur ing t h e 1970's when investigators found t h a t the excellent analytical fig ures of merit, including great sensitivi ty and low detection limits, were more t h a n compensated for by the complex physical and chemical interferences related t o t h e sample matrix. Although t h e inductively coupled p l a s m a - a t o m i c emission ( I C P - A E ) system did n o t flourish until t h e 1970's with t h e fine work of the Fassel, Greenfield, Robin, and B o u m a n groups, t h e initial articles utilizing t h e I C P for analytical work were p u b lished by Fassel a n d coworkers ( A N A L . C H E M . ) a n d by Greenfield a n d co
workers (Analyst) in t h e 1960's. Atomic fluorescence spectrometry
(AFS) as an analytical m e t h o d was conceived by Winefordner a n d co workers in t h e 1960's (those papers a p p e a r e d in A N A L . C H E M . ) . T . S. W e s t
and coworkers also published exten sively in analytical journals on atomic fluorescence spectrometry. C. T h . J. Alkemade, who mentioned t h e possi bility of analytical A F S in 1963, had several excellent papers a n d talks on the principles of A F S in t h e 1960's. Research on R F - a n d microwave-ex cited electrodeless discharge lamps as excitation sources in A F S flourished in t h e late 1960's a n d early 1970's. Although dc plasma sources were just described for analytical purposes in 1959 by M. Margoshes a n d B. F. Scribner in t h e U.S. a n d by V. V. Korolev a n d Ε. Ε. Vainstain in t h e USSR, these atomic emission sources were not utilized extensively until t h e 1960's when such workers as L. Owens, E. Kranz, J. H. McGinn, M. Yamamoto, W. G. Elliott, and R. E. J a h n gave experimental details (most of these p a p e r s did n o t a p p e a r in A N A L . CHEM.).
T h e Grimm discharge for atomic emission spectrometry, developed by W. Grimm in 1967-68 for t h e analysis of solids, received relatively little at tention by analytical spectroscopists until the 1970's. T h e laser microprobe, concerned in t h e 1960's for spatial profiles of trace elements in solids, seemed to struggle for survival. Image detectors for detecting multispectral components were not used by analytical spectroscopists until t h e 1970's. During t h e 1960's, several excellent reviews on atomic spectrometry, which "led t h e way", were published in ANAL. C H E M . and Appl. Spectrosc, and several new journals a p peared (Spectrochim. Acta split into Sections A a n d B, a n d Appl. Spectrosc. Rev. a n d Spectrosc. Letters a p peared b u t did n o t syphon many pa p e r s away from A N A L . C H E M . ) .
E l e c t r o c h e m i c a l M e t h o d s . During the 1960's, ion-selective electrodes were being developed by analytical chemists such as G. G. Guilbault, G. A. Rechnitz, R. G. Bates, J. W. Ross, M. F r a n t , E. Pungor, J . Ruzicka, G. Eisenman, and R. Buck. T h e most sig nificant works were published in ANAL. CHEM. or other general analyt ical journals by analytical chemists. Direct potentiometry, including t h e E D T A electrode of C. N . Reilley, nullpoint potentiometry of H. V. Malm s t a d t a n d J . D. Winefordner, a n d a greater understanding of t h e glass
electrode by G. Eisenman and R. G. Bates, also flourished in t h e l 9 6 0 ' s . C o m p u t e r s a n d A u t o m a t i o n . Ana lytical chemists were quick to utilize minicomputers to process data, con trol instrumentation, a n d a u t o m a t e processes. Such work was conducted by many analytical chemists including C. Enke, H. V. M a l m s t a d t , J . Fraser, R. Dessy, a n d F . McLafferty. Chemi cal uses of machine intelligence were extolled by such analytical chemists as T . L. Isenhour, P . C. J u r s , B. R. Kowalski, a n d C. N . Reilley. Most pa pers in this area were published in A N A L . C H E M . , w i t h a few being placed
in other analytical journals. M o l e c u l a r S p e c t r o s c o p y . Al though most of molecular spectrosco py was considered to be a n area of moderate activity for analytical chem ists (i.e., for analytical chemists to make substantial contributions to t h e instrumentation, t h e methodologies, and the principles), there were several areas of high activity. T h e s e areas in cluded: kinetic m e t h o d s of analysis, a u t o m a t e d clinical m e t h o d s of analy sis, a n d fluorimetric m e t h o d s for inor ganic ions. Research on kinetic a n d a u t o m a t e d m e t h o d s was actively pur sued in t h e 1960's by analytical chem ists such as H. V. M a l m s t a d t , H. L. P a r d u e , D. W. Marjerum, C. N . Reil ley, S. Siggia, H . Mark, and G. G. Guilbault. Research on fluorimetry of inorganic ions was primarily t h e do main of C. E. White a n d coworkers and H. Freiser, Q. F e r n a n d o , etc. Most of the papers on kinetic m e t h o d s , au tomated methods, enzymes, a n d fluo rimetry were published in A N A L . C H E M . , Talanta, or Anal. Chim. Acta. C h r o m a t o g r a p h y . During t h e 1960's, analytical chemists m a d e many contributions t o gas, liquid, thin-layer, and paper chromatography, although biological scientists also continued, as in t h e 1950's, to develop innovative procedures and instrumentation. T h e principles of gas and liquid chroma tography were expanded upon by workers such as J . D. Giddings, R. A. Keller, L. B. Rogers, L. R. Snyder, J. J. Kirkland, J . F . Huber, a n d R.P.W. Scott. Gas a n d liquid chromatographic detectors were being developed a t a frantic rate in t h e 1960's, including those based upon fluorescence, elec trochemical principles, and ionization phenomena. J . E . Lovelock and S. R. Lipsky h a d much to do with t h e devel o p m e n t of ionization detectors during the expansive years of GC. Others who were influential with detector design included C. H . H a r t m a n , S. Brody, L.
ANALYTICAL CHEMISTRY, VOL. 50, NO. 14, DECEMBER 1978 · 1303 A
50
YEARS Guiffrida, A. K a r m a n , M. Beroza, M. Bowman, a n d D. M. Coulson. Many of the most innovative fundamental and instrumental papers and t h e best reviews on gas a n d liquid chromatogr a p h y were p u b l i s h e d in A N A L . C H E M .
although t h e newly developed specialized journals such as J. Chromatogr. Sci., Sep. Sci., a n d J. Chromatogr. received the major n u m b e r of articles. P a p e r and thin-layer chromatography were used by many analytical chemists, b u t few truly innovative aspects of the fundamental, methodologies, or instrumentation occurred in the 1960's. Gel permeation chromatography was little used by analytical chemists. Moderate Activity Areas in the 1960's M o l e c u l a r S p e c t r o m e t r y . During the 1960's, t h e " h e a r t " of modern analytical chemistry, U V - V I S molecular (electronic) absorption spectrometry, was described in numerous papers published in ANAL. C H E M . , Talanta, and Anal. Chim. Acta a n d other general journals, b u t few really novel analytically important ideas concerning instrumentation or methodologies resulted. T h e same comment could be applied to IR absorption/emission spectrometry, R a m a n spectrometry, and optical rotatory dispersion/circular dichroism (ORD/CD). It was not until t h e 1970's t h a t t h e really innovative papers on semiconductive diode lasers with their small (~10~ 4 c m - 1 ) spectral bandwidths were utilized for IR absorption of gases. Also, it was not until t h e 1970's t h a t analytical spectroscopists began to use R a m a n spectrometry, especially t h e nonlinear effects, extensively, for analysis. Use of the latter effects was limited due to the lack of availability of intense, "inexpensive", and commercially available pulsed and CW tunable dye lasers. In addition, the majority of t h e really innovative studies on O R D / C D , Raman, a n d IR absorption spectrometry (including Fourier a n d H a d a m a r d transform methods) were being performed in t h e 1960's by physicists and physical chemists. This is not to say t h a t good science by analytical chemists was not being carried out, b u t rather t h a t analytical chemists had little to do with the direction of t h e fundamentals, t h e instruments, or much of t h e methodologies of these areas. On the other hand, research efforts on instrumentation and methodologies in molecular (electronic) lumines-
cence spectrometry (fluorimetry a n d phosphorimetry) were d o m i n a t e d by analytical a n d physical chemists during t h e 1960's. M a n y of t h e benchmark papers were published in A N A L . C H E M . , a n d several in Appl. Spectrosc, Anal. Chem. Acta, a n d Talanta by such workers as L. B. Rogers, D. M. Hercules, E. Sawicki, C. A. Parker, C. E. White, P . V. Drushel, B. L. Van Durren, a n d J . D. Winefordner. However, research efforts on microfluorimetry, t h e fundamentals of luminescence including lifetime measurements, t h e use of fluorescence polarization, t h e use of delayed fluorescence, the determination of protein and nucleic acid structures via binding of fluorophors, a n d covalent fluorescent labeling were primarily performed by physical a n d biological chemists. Quantitative microwave absorption spectrometry was being used for small molecule analysis in t h e late 1960's by analytical spectroscopists, e.g., F. T . Funkhouser a n d H . W. Harrington. Unfortunately, instrumental costs limited t h e use of microwave spectrometers to only a select few. Several excellent reviews in A N A L . C H E M .
were not sufficient t o generate great vigor in this area. A n u m b e r of analytical chemists in the 1960's, including H. V. M a l m s t a d t , H. L. P a r d u e , D. W. Margerum, a n d C. N . Reilley, made considerable contributions t o t h e instrumentation a n d methodologies of stopped flow, temperature a n d pressure j u m p , and relaxation methods for reaction rate techniques. Many of t h e best articles on stopped flow, T-jump, P-jump, and relaxation methods appeared in A N A L . CHEM. However, many of the really innovative instrumental a n d fundamental studies were performed by physical chemists. E l e c t r o c h e m i c a l Methods. Although a renaissance, as noted by articles in A N A L . C H E M . a n d t h e special-
ized electrochemistry journals, was beginning in polarographic analysis in the late 1960's, it was n o t clearly evid e n t until t h e early 1970's. Electrochemical methods, t h e mainstay of analytical chemistry during t h e 19401950's, continued to be researched by perhaps more t o p analytical chemists than any other area. Nevertheless, during t h e 1960's, there was a definite trend away from electrochemical m e t h o d s by young analytical chemists. In the late 1960's and 1970's, electrochemical methods were rejuvenated by the introduction of sophisticated
1304 A · ANALYTICAL CHEMISTRY, VOL. 50, NO. 14, DECEMBER 1978
commercial electrochemical instrum e n t a t i o n for differential pulse polarography, ac polarography, fast linear sweep polarography, direct a n d pulsed stripping voltametry, etc. This allowed greater sensitivity and resolution t h a n with dc polarography a n d organic as well as inorganic analysis of many samples. During t h e 1960's, t h e modern m e t h o d s mentioned above were under development by analytical chemists such as I. Shain, P . Delahay, H . A. Laitinen, J. Flato, R. A. Osteryoung, G. C. Barker, S. Bruckenstein, W. Kemula, B. Breyer, a n d F. Anson. Dc polarography, amperometric, electrolytic, and coulometric methods, on t h e other hand, were still in great use by scientists, b u t relatively few i n s t r u m e n t a l and methodological developments a p peared in t h e 1960's. Magnetic Resonance Spectroscopy. Magnetic resonance spectroscopy during t h e 1960's was primarily used by physicists a n d physical chemists who developed much of t h e instrum e n t a t i o n a n d most of t h e fundamental aspects of nuclear magnetic resonance ( N M R ) , electron magnetic (spin) resonance (ESR), nuclear quadrupole resonance (NQR), double resonance techniques, pulsed magnetic resonance, and spin echo techniques. Only in t h e area of N M R were analytical chemists (see Table I) influential in developing innovative methodologies in the 1960's. Innovative works were carried out on t h e quantitative analysis of mixtures, molecular weight determination, polymer analysis, analysis of surfactants, drug analysis, protonation schemes of polyfunctional ligands, protonation schemes of metal complexes, stability of metal complexes, a n d exchange reactions involving metal complexe^. Analytical chemists highly active in these areas included C. N . Reilley, D. T . Sawyer, R. J. Kula, J . L. Sudmeier, D. L. Rabenstein, D. E. Leyden, D. P . Hollis, W. D. Cooke, and J. N. Schoolery. It should also be stressed t h a t T . C. Farrar had considerable input into t h e development of t h e pulsed N M R (Fourier transform). All of these workers published significant papers in ANAL. C H E M . as well as more physically related journals such as J. Am. Chem. Soc. and J. Phys. Chem. T h e r m a l Methods. During t h e 1960's, W. W. W e n d l a n d t , E. M. Barrail, J. J. J o r d a n , and others m a d e significant contributions to the use of thermal methods (thermogravimetry, differential scanning calorimetry, and
IfËÂSS enthalpimetry). Many of these papers were published in ANAL. C H E M . , Anal. Chim. Acta, and other general analytical, inorganic, and physical journals. N u c l e a r / X - r a y Spectroscopy. Research efforts by analytical chemists in neutron activation analysis (NAA), photon activation analysis (PAA), charged particle activation analysis (CPAA), and X-ray fluorescence spectrometry (XRS) and key articles in A N A L . C H E M . and other analytical journals seemed to abound in the 1960's. Specialized journals on nuclear/X-ray spectroscopy appeared in the late 1960's and early 1970's. The
detection and source instrumentation for activation analysis and X-ray fluorescence, namely, solid state detectors (SiLi, GeLi), energy dispersion, prompt radiation techniques, radioisotope sources, high-energy particle sources, and electron sources, developed rapidly. Workers in these areas included G. H. Morrison, R. Jenkins, L. B. Birks, K. Heinrich, V. P. Guinn, J. P. Cali, V. Krivan, E. Ricci, G. F. Lutz, G. Giraldi, W. W. Meinke, 0 . Anders, J. R. DeVoe, P. LaFleur, and J. Ruzicka. Radiometric methods of analysis were refined during the 1960's, including the use of radioactive indicators, radioactive reagents, radio-
metric titrations, and radioisotope dilution by analytical chemists such as W. W. Meinke and W. J. Driscoll. Radiochemical separations also received considerable input by analytical chemists by many of the same workers as listed above. The electron microprobe was refined in the 1960's, with instrumental improvements such as linear spectrometry, the use of multilayer stéarate crystals for light elements, brighter electron sources, and energy dispersion. Quantitative analysis of low concentrations of elements in small areas of solid samples was actively pursued by analytical chemists. Researchers
Table I. Tabulation of 1960-1970 References to the JOURNAL, ANALYTICAL CHEMISTRY, Based on Biennial Reviews in ANALYTICAL CHEMISTRY
Area
Total AC refs
% of refs published In A C »
Atomic spectrometry AAS,bdAES,cdAFSd AES e
820 2863
11.8H 6.2 H
Nuclear/X-ray spectrometry Nucleonics Electron microscopy X-ray diffraction X-ray absorption/fluorescence Mossbauer spectrometry
4675 1754 1394 3056 1997
7.4 1.4 2.4 6.7 0.4
Electrochemistry Electroanalysis, coulometric analysis Electrophoresis Polarography (includes organic) Amperometric titrations Potentiometric titrations (includes nonaqueous titrations) Electrochemical relaxation Molecular spectrometry Fluorimetry, phosphorimetry Light absorption spectrometry UV absorption spectrometry Raman spectrometry Infrared absorption spectrometry Light scattering Chromatography Gas chromatography Ion exchange Chromatography: liquid, paper, thin-layer a
Ν L L H L
1650 7538 7121 1671 4130
12.9 M 0.2 Ν 7.2 M 5.6 M 13.2 H
455
33.8 M
3213 3804 1960 1751 2093 857
6.1 13.6 12.3 0.6 4.5 0.4
H M M M-L M Ν
3451 2428 5870
16.5 Η 10.3 Η 8.1 Η
Rounded to nearest tenth of a percent. H. high activity area; M, moderate activity area; L, low activity area; N, not directly discussed here. b AAS (atomic absorptionflame spectrometry) was reviewed separately in 1962. c AES (atomic emission-flame spectrometry) was reviewed separately in 1962. d Flame and furnace spectrometry (AAS, AES, and AFS-atomic fluorescence spectrometry) was reviewed as an area starting in 1970. e AES (atomic emission-high-energy plasma spectrometry) was re viewed as an area from 1962 to 1970. In 1962 flame emission was removed from this area review. ' NMR (nuclear magnetic resonance) was reviewed in 1964, 1966, 1968, and 1970. flESR (electron spin paramagnetic resonance) was reviewed only in
% of refs published In A C
Area
Total AC refs
Chromatography Ε lectrochromatography Extraction Distillation
184 3894 1126
5.9 Ν 7.5 Ν 2.0 Ν
Magnetic resonance spectrometry NMR f ESR° Magnetic resonance'' Magnetic susceptibility
4198 1300 439 1841
1.7 0.0 1.5 0.6
M M M Ν
Mass spectrometry
6108
2.8 M
Thermal methods
1560
7.6 M
Other areas Enzymes ' Kinetic methods' Enzymes and kinetic methods'' Gas analysis ' Functional group analysis'" Organic elemental analysis " Biochemical analysis 0 Inorganic analysis' 7 Chemical microscopy Inorganic microchemistry 0 Organic microchemistry'' Statistical methods s Volumetric methods '
624 353 555 910 255 260 1977 145 1961 827 1709 808 2125
8.4 H 20.6 H 9.7 H 8.2 Ν 7.0 Ν 10.0 Ν 10.6 Ν 17.2 Ν 1.7 Ν 27.8 Ν 14.3 Ν 5.9 Ν 15.2 Ν
Total references 1960-1970 in AC biennial Reviews = 97 315 References to the JOURNAL A N A L Y T I C A L CHEMISTRY = 6694
Percentage of references in AC = 7.2 1966-1968. h Magnetic resonance was reviewed collectively in 1962, 1964. ' Enzyme analysis reviewed in 1966, 1968. 'Kinetic methods reviewed in 1962, 1964, 1968. k Both kinetic and enzyme methods were reviewed collectively in 1970. ' Gas analysis methods reviewed only through 1966. m Functional group reviewed only in 1970. " Organic elemental analysis reviewed only in 1970. ° Biochemical analysis reviewed in 1962, 1964, 1966, 1968. p Inorganic analysis reviewed only in 1970. ''Inorganic microchemistry reviewed in 1962, 1964, 1966. r Organic microchemistry reviewed in 1962, 1964, 1966, 1968. s Statistical methods reviewed through 1968. 'Volumetric methods reviewed through 1968.
ANALYTICAL CHEMISTRY, VOL. 50, NO. 14, DECEMBER 1978 · 1305 A
included L. S. Birks a n d K. Heinrich. M a s s S p e c t r o m e t r y . Mass spec trometry, which was primarily a tool of physicists a n d physical chemists through t h e 1950's, was actively pur sued by analytical chemists in t h e 1960's. Many of the best articles were published in A N A L . C H K M . , although
many also appeared in specialized journals as well as physical chemistry journals and other general analytical journals. Analytical chemists made significant contributions on t h e use of mass spectrometry for analysis (F. W. McLafferty, K. Biemann, M. M. Bursey, a n d J. H. Beynon). Ion cyclo tron resonance spectrometry was just being used by analytical chemists
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based on t h e A N A L . C H K M . review by
J.M.S. Henis in 1969. Spark source mass spectrometry was being devel oped as an analytical quantitative tool by such workers as G. H. Morrison and R. E. Honig. Chemical ionization mass spectrometry was used little in the 1960's by analytical chemists. Quadrupole mass spectrometers also had not emerged yet as a sensitive an alytical tool. T h e marriage of gas chro matography a n d mass spectrometry became a reality in t h e 1960's, al though much of the work was by nonanalytical chemists. L o w to N o Activity in t h e 1 9 6 0 ' s
Areas
N u c l e a r / X - r a y Spectroscopy. Al though certain nuclear research areas received great input from analytical chemists, several areas received little or no input because of the newness of the methods, t h e lack of commercial equipment, t h e lack of any a p p a r e n t analytical use, and t h e requirement of highly specialized equipment. These areas included electron spec troscopy (ES) (e.g., X-ray excited, UV photon excited, ion scattering, Auger, backscattering, electron diffraction, and electron impact); small angle neu tron scattering (NS); Mossbauer spec troscopy (MS); electron microscopy (EM); ion microprobe analysis (IMA); and X-ray diffraction (XRD). Several areas of ES were t o emerge as exciting methods of analysis in t h e 1970's. Both N S a n d M S were utilized almost exclusively by physicists, physical chemists, a n d solid state chemists a n d physicists in t h e 1960's a n d even in the 1970's. T h e IMA also emerged in the 1970's as a unique technique for ultratrace analysis of elements spatial
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1306 A · ANALYTICAL CHEMISTRY, VOL. 50, NO. 14, DECEMBER 1978
ly present in samples; however, t h e 1960's were t h e years for physicists and physical chemists to develop in s t r u m e n t a t i o n a n d principles. X R D continued to be a service tool for structure analysis primarily by organ ic, inorganic, and biological chemists and was little used by analytical chemists, especially from t h e instru mental, methodological, or fundamen tal sides (Table I). Most specialized journals on nuclear, electron, a n d X-ray spectrometry emerged in t h e 1970's; therefore, most analytical arti cles a p p e a r e d in A N A L . C H K M . ,
Anal.
Chim. Acta, etc., as well as in Appl. Spec t rose. L a s e r s . Except in t h e area of laser microprobes (workers like F. Brech, H. V. Malmstadt, E. Piepmeier, a n d D. Click) and Raman spectrometry, lasers were virtually n o t used by ana lytical chemists. T h e use of tunable dye lasers by analytical chemists for atomic fluorescence spectrometry, mo lecular luminescence spectrometry, and nonlinear R a m a n spectrometry emerged within t h e early to mid1970's. An interesting review on tun able lasers a p p e a r e d in A N A L . C H K M .
in 1969. T h e first analytical papers with lasers in A N A L . C H E M . (other
t h a n t h e laser microprobes) appeared several years later. T a b u l a t i o n of R e f e r e n c e s to ANALYTICAL CHEMISTRY
as
D e t e r m i n e d by Biennial Reviews ( 1 9 6 0 - 1 9 7 0 ) in A N A L Y T I C A L
CHEMISTRY
In Table I t h e reader can refer to such a tabulation and observe t h a t t h e frequency of references is approxi mately in accordance with t h e areas of high, moderate, a n d low activity as designated in t h e present manuscript. This general agreement or ordering of priorities indicates t h a t the -JOUR NAL A N A L Y T I C A L C H E M I S T R Y k e p t
pace with t h e areas of high a n d mod erate activity in t h e area of analytical chemistry, at least in t h e eyes of this reviewer. T h e areas of low activity are generally those t h a t were just being developed by physicists a n d physical chemists as analytical methods (e.g., Mossbauer, electron spectroscopy, light scattering, R a m a n spectrometry, ESR, N M R , a n d certain areas of mass spectrometry) and those t h a t emerged in t h e next decade as bona fide analyt ical methods.
