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In the more than 100 years since Russian botanist M. S. Tswett pioneered the development of chromatography to separate plant components, the basic nature of chromatography columns has remained unchanged. In all that time, practitioners have been separating chemical mixtures by using columns packed with various types of particulate matter. Nobuo Tanaka, a professor in the department of biomolecular engineering at Kyoto Institute of Technology, took a radically different approach. He developed columns that feature one-piece, porous, solid silica packings known as monoliths.
Tanaka has made several important contributions to various areas of chromatography, says Georges Guiochon, a chemistry professor at the University of Tennessee, Knoxville. However, Tanaka's most important contribution is "the development and reduction to practice of monolithic silica columns for HPLC," Guiochon says. The advent of monolithic packings is the single most important advance in the preparation of chromatography columns since the work of Tswett a century ago, he adds. Because of monolithic columns' major impact on analytical chromatography, this development alone, in Guiochon's view, makes Tanaka an ideal recipient of the award.
Monolithic chromatography columns were the focus of a cover story in Chemical & Engineering News (Dec. 11, 2006, page 14). These nontraditional column materials, which were recently commercialized, have been used in various applications such as separating proteins, peptides, oligonucleotides, and other types of analytes. Manufacturers and users alike report that for various types of separations, monolithic columns offer the possibility of outperforming traditional columns in terms of chromatographic resolution, separation speed, and thoroughness in separating complex mixtures of biological and other types of molecules.
Koji Otsuka, a professor of materials chemistry at Kyoto University, notes that Tanaka's pioneering work has now led to second-generation HPLC silica monoliths that are poised to have a strong impact on high-speed separations. These columns offer some of the separations benefits of modern ultra-HPLC instrumentation, Otsuka says, but without the high price tag of the newer chromatographs.
In addition, modifying silica monoliths via polymerization of various functional groups has enabled these one-piece stationary phases to be used effectively for ion exchange, hydrophilic interaction, size exclusion, and other modes of separations, Otsuka notes. He adds that these polymer-modified monolithic silica columns outperform conventional particle-packed columns in several ways.
In one recent demonstration of the separation power of extremely long monoliths, Tanaka showed that benzene and monodeuterated benzene, which in many ways are nearly identical, can be separated readily on an 8-meter silica monolith (Anal. Chem. 2008, 80, 8741). Superlong monolithic columns aren't yet available commercially, but Tanaka predicts that 5–10-meter columns will be used practically within a few years.
Tanaka, 63, completed his formal education in chemistry at Kyoto University. In 1968, he graduated with a bachelor's degree, and two years later, he completed a master's degree. In 1973, he received a D.Sc. degree in chemistry, also from Kyoto University. He then moved to the U.S. for six years of postdoctoral research, spending two years each at the University of Pennsylvania; the University of Washington, Seattle; and Northeastern University. In 1979, Tanaka returned to Japan to take up a position as instructor at Kyoto Institute of Technology. He was named associate professor there in 1987, and in 1991, he was promoted to professor.
Tanaka has published nearly 200 scholarly papers and book chapters. He has served as editor of the Journal of Chromatography A and the Journal of Separation Science for 10 years and also serves or has served as an editorial board member of those and other journals.
Tanaka will present the award address before the Division of Analytical Chemistry during the fall national meeting in Washington, D.C.