(Potsdam , N Y )
PROF. D R W. K E M U L A -
A CATALYST OF E L E C T R O C H E M IC A L R E S E A R C H A N D A F R IE N D
P rofessor W iktor K em ula influenced profoundly the developm ent o f elec- troanalytical chem istry in the tw entieth century. He w as instrum ental in initia ting research in num erous areas o f electrochem istry, w hich played an im portant role in the later developm ent o f electroanalytical techniques. A n im portant m o m ent in his scientific career w as a visit he paid to the laboratory o f Prof. Jaros- lav H eyrovsky in P rague in the late tw enties. H ere in the D epartm ent o f P hysi cal C hem istry o f the C harles U niversity research w as in progress w hich laid scientific and rigorous foundations to the developm ent o f polarography, using electrolysis w ith the dropping m ercury electrode.
A fter return to Poland, Professor K em ula, in continuation o f his w ork in P ra gue, first observed and reported the dependence o f lim iting currents on the w eight o f m ercury and its surface area12. This observation was one o f the expe rim ental facts, w hich lead later D. Ilkovic to the derivation o f an equation, d e scribing the dependence o f lim iting currents on concentration o f the electro acti ve species, its diffusion coefficient, on the num ber o f transferred electrons, rate o f form ation o f m ercury drops and on the size o f these drops5.
Sim ilarly, Professor K em ula w as the first to indicate the possibility o f follo w ing electrolysis products by follow ing their form ation, after alternatively applying a potential and m easuring currents corresponding to electrolyses o f products form ed4. This principle has been later developed by M. K alousek and * Department o f Chemistry, Clarkson University, Potsdam, NY 13699-5810 USA. Kwartalnik Historii Nauki i Techniki R. 47: 2002 nr 1 s. 83-88
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Fot. 26. Prof. Wiktor Kemula, 1983.
rectangular voltage polarization o f the w orking electrode w as used in his „com m utator m ethod”5. B asically the sam e principle w as used by G. B arker in the pulse and square w ave polarography6' 7> 8, w hich, because o f their high sensitivi ty, form ed the basis o f differential pulse polarography, and the variant o f the square w ave polarography introduced by J. O steryoung9. T hese variants o f po la rography becam e the m ost w idely used in practical analysis and their develop m ent saved the technique from obsolescence.
A nother im portant contribution o f Professor K em ula w as the introduction o f the hanging m ercury drop electrode (H M D E) into electroanalysis in his w ork w ith Z. K ublik10. This type o f electrode, that offers the clean surface o f m ercu ry and at the sam e tim e a constant electrode surface, is now adays probably the m ost frequently used type o f electrode for obtaining voltam m etric current-volta- ge curves. The use o f this electrode enables also accum ulation o f the analyte at the electrode surface. W hen such m aterial is electrochem ically stripped, the re sulting current-voltage curves enable analyses o f nanom olar, som etim es even pi- com olar solutions, w hich bring these electroanalytical m ethods to m ost sensiti ve existing ones. This electrode enables obtaining inform ation bridging those, obtained w ith dropping m ercury electrode (D M E), m ercury pool electrodes, and even solid electrodes. B ut w hereas the potential o f the D M E rem ains during the life o f each single drop practically constant, the potential o f the stationary
Fot. 27. Na przyjęciu z okazji Konferencji Polarograficznej w Warszawie i przyznania prof. Heyrovskiemu doktoratu h.c. Uniw. Warszawskiego, 1956 r. Siedzą przy stole, od prawej: Michał Śmiałowski (Warszawa), Wiktor Kemula, przemawia Jaroslav Heyrovsk(, Maria Kemulowa, Alina Vincenz, Karol Butkiewicz, Stanisław Rubel. electrode is varied as a function o f tim e during the recording o f each current-vol- tage curve. This offers the possibility to use the scan rate as an additional p ara m eter in investigation o f electrode processes, but has the lim itation that products generated at one potential m ay interact w ith species present o r form ed at a d if ferent potential.
W hen a triangular voltage sw eep is used in cyclic voltam m etry, H M D E p ro ved to be very useful in investigation o f reversibility o f electrode processes and in the studies o f chem ical reactions o f products o r interm ediates o f electrode processes. F urtherm ore, H M D E is w ell suited for the use in controlled potential electrolyses (chronoam perom etry), w hich also offers a further insight into m e chanism s o f electrode processes. It is to be regretted that in.the view o f its w ide use, H M D E is not m ore frequently connected w ith nam es o f its originators, Prof. W. K em ula and Z. Kublik.
The last area to be m entioned, in w hich Professor K em ula m ade a sem inal con tribution to the developm ent o f electroanalytical techniques, w as the developm ent o f the first hyphenated m ethod in analytical chemistry. B y using a D M E as a de tector in colum n11 and in paper12 chromatography, by com bining chrom atography and polarography, a new m ethod, „chrom ato-polarography” w as b o m in the fifties, long tim e before o ther techniques w ere used in tand em w ith chrom atography. C om bination o f various form s o f separation techn iq ues w ith electro chem ical
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detection is currently the most frequently used application o f electrochemistry in ana lytical practice. Again, the importance and timeliness o f Prof. K em ula’s contribution to m odem analytical chemistry is not as widely recognized, as would be deserved.
Yet in another aspect P rofessor K em ula m ade an im portant contribution to the developm ent o f contem porary electroanalytical chem istry. P rofessor K em u la had the ability to attract good, bright young collaborators. H is enthusiasm and insight into electrochem ical research rubbed o ff on his collaborators and resul ted in a form ation o f a w ell renow ned school. Som e o f his collaborators left the area o f electroanalytical chem istry and becam e prom inent in other areas o f p hy sical, analytical and inorganic chem istry, w hich reflects a healthy interbreeding o f chem ical disciplines. B ut considerable num ber o f his collaborators rem ained true to their electrochem ical credo and contributed to such grow th o f electroana lytical chem istry in Poland that this country becam e an exporter o f electroche m ical talent. W ithout doubt, P olish electrochem ists currently represent the lar gest and strongest group o f those, w ho have no t been b o m W est o f the Atlantic, w ho achieved prom inence in electrochem istry on the N orth A m erican continent. T heir contributions to the developm ent and practical uses o f electroanalytical techniques continue to have a large impact.
Fot. 28. Spotkanie naukowo-towarzyskie w mieszkaniu pp. Kemulów, 1956 r.. prof. Wiktor Kemula, prof. Wojciech Świętosławski, prof. Jaroslav Heyrovskÿ, prof.
P rofessor W. K em ula understood w ell the im portance o f international coo p e ration in science. It w as m y pleasure to consider him an older friend, a re la tionship w hich w as initiated during m y first trip to abroad, w h en in 1953 I could spend 5 w eeks in his laboratories. A fter that w e m et at m eetings in som e p ro b ab le and even less probable com ers o f the w orld. We attended jo in tly the m eetings o f the C om m ission V-5 on E lectroanalytical C hem istry o f the International U nion o f P ure and A pplied Chem istry, w here he contributed considerably to international cooperation. H is contribution w as ackow leged as he becam e the P resident o f the A nalytical D ivision o f IUPAC.
Last but not least, Professor K em ula w as a m an o f culture. It was m y pleasure at num erous dicussions w e had at various localities to observe, how close w ere our opinions not only about science, but also about hum an relationships, history, p oli tics and art. Professor K em ula w as a real gentlem an and it w as o f no surprise that he attracted friendship o f colleagues from all over the world. His too early depar ture from this w orld was m ourned by m any friends in all parts o f the globe.
References
1 W. K e m u 1 a : Les recherches sur les courants de saturation p ar diffusion des ca tions à l ’aide d ’une électrode à gouttes de mercure d ’après Kucera-Heyrovsky. „Trabajos del IX Congresso Intemacional de Quimica Pura y Applicada“, Madrid 1934 Vol. II „Qimica-Fisica“ s. 297-303.
2 W. K e m u l a i B. W e n i g e r ó w n a : Badania polarograficzne. Pomiary prądów granicznych w roztworach czystych soli za pomocą kroplowej elektrody rtęcio
wej Kucery-Heyrovsky’ego. „Roczniki Chemii“ 1934 14 406-413.
3 D. 1 1 k o v i ć : Polarographical studies with the dropping mercury kathode. Part XLIV. The dependence o f limiting currents on the diffusion constant, on the rate o f drop ping and on the size o f drops. „Collection of Czechoslovak Chemical Communications”
1934 6 498-513.
4 W. K e m u l a : Polarographic studies with the dropping mercury cathode. Part XIV. A study o f the discontinuities on curves obtained in solutions o f mercuric cyanide. „Collection of Czechoslovak Chemical Communications“ 1930 2 502-519.
5 M. K a l o u s e k : Processes at the dropping electrode with a discontinuously chan ging potential. „Collection of Czechoslovak Chemical Communications” 194813 105-115.
6 G.C. B a r k e r and I.L. J e n k i n s : Square-Wave Polarography. „Analyst“ 1952 77 685-696.
7 G.C. B a r k e r : Square-Wave Polarography and Some Related Techniques. „Analytica Chimica Acta“ 1958 18 118-131.
8 G.C. B a r k e r and A.W. G a r d n e r : Pulse polarography. „Zeitschrift fiir Ana- lytische Chemie“ 1960 173 79-83.
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9J. O s t e r y o u n g and C. W e c h t e r : Development ofpulse polarography and voltammetry. „Electrochemistry - Past and Present“ (J.T. Stock and M.V. Oma, eds.) „ACS Symposium Series“ 1989 390 380-395.
10 W. K e m u 1 a iZ . K u b l i k : Zastosowanie nieruchomej „wiszącej“ elektrody rtęciowej do badań oscylopolarograficznych . „Roczniki Chemii“ 1956 30 1005-1008.
11 W. K e m u 1 a : Badania chromato-polarograficzne. I. Rozważania ogólne i opis aparatury. „Roczniki Chemii“ 1952 26 281-287.
12 W. K e m u 1 a : Chromato-polarograficzna analiza mieszanin jonów na bibule. I. Analiza mieszanin jonów o jednakowym potencjale pół-fali. „Roczniki Chemii“ 1952 26
