(b. Laibach, Austria [now Ljubljana, Yugoslavia], 3 September 1869; d. Graz, Austria, 13 December 1930)
Pregl’s father, Raimund Pregl, a bank treasurer in Carniola, died when his son was still young. His mother was Friderike Schlacker. In 1887, after graduating from the Gymnasium in Laibach, he entered the University of Graz to study medicine. He spent almost his entire career at this university. His mentor in physiology quickly recognized Pregl’s abilities and made him an assistant in his laboratory before he had completed his studies. Following his graduation, he remained at the laboratory but also practiced medicine, specializing in ophthalmology.
Although Pregl gained a thorough knowledge of physiology, his interest soon turned to physiological chemistry. He became an outstanding experimenter and investigated the reactions of cholic acid and the causes of the high values of the carbon : nitrogen ratio in human urine. The latter research qualified him in 1899 for the post of university lecturer in physiology. To broaden his scientific knowledge, Pregl spent a year (1904) in Germany, where his preference for chemistry became stronger. He studied physiological chemistry with Carl Hüfner at Tübingen, physical chemistry with Wilhelm Ostwald at Leipzig, and organic chemistry with Emil Fischer. At Berlin he also investigated the hydrolysis products of egg albumin with E. Abderhalden, who became a lifelong friend.
After his return to Graz, Pregl became an assistant at the medical-chemical laboratory of the university; he studied bile acids and also conducted research in protein chemistry. From these investigations he repeatedly found that the analytical methods of organic chemistry were too complicated, lengthy, and inexact for the determination of the composition of materials of biochemical origin. Such methods also required large test samples, which were often difficult to obtain with organic substances.
Pregl thus set himself the task of making the classical methods of elementary analysis feasible on a microscale. He approached this problem as a physiological chemist, hoping to create a suitable method for his investigations. The problem, however, proved to be more complicated than expected, and it gradually claimed his full attention. Organic microanalysis increasingly became the focus of his research, and he found that the methods of analytic chemistry were essential.
Pregl’s methods did not deviate in principle from those of Liebig and Dumas; but now only one to three milligrams were sufficient for a determination, which could also be executed much more quickly and exactly. To create the necessary apparatus, this transformation of methods required a great deal of effort and technical skill, and it was of such importance that Pregl was awarded the Nobel Prize in chemistry.
In 1910 Pregl was appointed professor of medical chemistry at the University of Innsbruck, where he was able to realize his plans. His first task was to find a balance more sensitive than that used in analytical chemistry. W. H. Kuhlmann had recently constructed balances for the determination of noble metals that measured with an exactness of 0.01 to 0.02 milligrams. Pregl found that with smaller quantities and under suitable circumstances measurements could be made with an exactness of ± 0.001 milligrams. He soon established methods for the microdetermination of carbon and hydrogen; these methods were followed by others for determining nitrogen, halogen sulfur, carboxyl, and other substances. Pregl extended his research to include a broad range of organic substances; and in 1917 he published Die quantitative organische Mikroanalyse, which was preceded by only a short publication in Abderhalden’s Handbuch der biochemischen Arbeitsmethoden. Pregl’s book underwent numerous and frequently revised editions and was translated into several languages.
Pregl’s development of microanalysis was an immeasurable advance in both science and industry, and much of the groundwork in biochemistry evolved from his developments. In 1923, only six years after the appearance of his book, he was awarded the Nobel Prize—the first to be awarded for accomplishments in the field of analytical chemistry.
In 1913 Pregl had been recalled to Graz; he was named professor of medical chemistry and was active in research until his death. (His laboratory had become a world-renowned center of organic microanalysis.) Pregl was an earnest, energetic man, often given to sarcastic humor. He frequently engaged in mountain climbing and bicycling and was an enthusiastic automobile driver. He never married.
Pregl’s major work is Die quantitative organische Mikroanalyse (Berlin, 1917; 2nd ed., 1923; 3rd ed., 1930), 4th ed., revised with supp., von Hubert Roth, ed. (Berlin, 1935); later eds. were published in Vienna.
On Pregl and his work, see H. Lieb, “Fritz Pregl,” in Berichte der Deutschen chemischen Gesellschaft, 64A (1931), 113, and “Fritz Pregl,” in Mikrochemie, 3 (1931), 105. See also R. Strebinger, “Fritz Pregl,” in Österreichische Chemikerzeitung, 34 (1931), 10; F. Szabadváry, History of Analytical Chemistry (Oxford-New York, 1966), 302-303, and Geschichte der analytischen Chemie (Brunswick, 1966), 304-305.
The Austrian physiologist and medical chemist Fritz Pregl (1869-1930) developed the methods of quantitative organic microanalysis.
Fritz Pregl was born on Sept. 3, 1869, in Laibach, now Ljubljana in Yugoslavia, but then a provincial capital in the Austro-Hungarian Empire. After the death of his father, a bank official, he moved in 1887 with his mother to Graz, the seat of a university. There he studied medicine and obtained his medical degree in 1894.
As a student, Pregl had been interested in physiology and upon graduation became a teaching assistant in the Physiological Institute of the university. He remained in this field as he rose on the academic ladder to attain the rank of associate professor in 1904. However, he had meanwhile also been attracted to, and become quite adept in, organic chemical laboratory research, and indeed his publications from that period reveal a strong predilection for the chemical aspects of physiology as well as for the methodological. This partial switch in his research interests became complete when, after taking a long leave of absence, he transferred his activities to the Institute of Medical Chemistry in Graz. In 1910 Pregl was called to the University of Innsbruck as full professor and head of the Institute of Medical Chemistry, only to return 3 years later in the same capacity to Graz, where he remained until his death on Dec. 13, 1930.
Pregl's great contribution to chemistry and medical science was the creation, in the years 1910-1917, of the methods of quantitative organic microanalysis. This made it possible to determine quantitatively the elements and some functional groups in organic compounds in samples weighing far less (3-5 milligrams) than was required in the procedures previously in use (100-200 milligrams).
Pregl's micromethods quickly became an invaluable tool to the organic chemist and a truly indispensable one to the biochemist. The micromethods greatly aided and accelerated the elucidation of the chemical structure of many biologically active substances of natural origin, such as hormones and vitamins, and were generally instrumental in the solution of a host of important biochemical problems. Of the many scientific honors bestowed on Pregl in recognition of this achievement, the most outstanding was the Nobel Prize for chemistry in 1923.
Pregl was an inspiring teacher who knew how to flavor his lectures with instructive experiments as well as with humor. In the 1920s chemists from all over the world flocked to his laboratory to receive instruction in microanalysis, often by him personally, in courses given practically free of charge.
A good profile of Pregl is in Eduard Farber, ed., Great Chemists (1961). There are also short biographies in Aaron J. Ihde, The Development of Modern Chemistry (1964), and Nobel Foundation, Chemistry: Including Presentation Speeches and Laureates' Biographies, vol. 2 (1966). □