ABSTRACT
I. HISTORICAL PERSPECTIVE I received my doctorate in 1973 under Professor Daido Ishii, Department of Applied Chemistry, Nagoya University, a well respected scientist who is considered one of the best Japanese separation scientists. My project was not on separation sciences. My degree was awarded on radioanalytical chemistry; my thesis was entitled "Nondestructive Determination of Various Elements by Neutron Activation Analysis." After receiving the degree, I worked at Toshiba Research and Development Center until 1978, when I moved to an academic position. At Toshiba I was working in lithography for super large-scale integrated circuits, an active and interesting field. In 1977 I met Professor Tsugio Takeuchi, a member of the Department of Applied Chemistry, Nagoya University, at that time, and he asked me about my work at Toshiba. A few months after our meeting I received a letter from the Japanese Ministry of Education and Culture stating that I was selected as one of the committee members to discuss new concepts for a new technical institution that would be built in Toyohashi. Since Professor Takeuchi's name was on the members' list, I phoned him inquiring about this offer. He said that since I had told him that university work would be nicer because we could do what we wanted, he chose me to be a faculty member of a new national technological university. After a long period of discussion between Toshiba and Professors Ishii and Takeuchi, I finally moved to the Toyohashi University of Technology (TUT) as an associate professor in April 1978, when the university has just opened. Professor Takeuchi had expected me to work in radiochemistry using an accelerator to be built on the new campus. Unfortunately, the machine never appeared in our TUT campus because Professor Takeuchi, the chief investigator of this project, died suddenly in the summer of 1979. No one continued this accelerator project, and I had to find a new project for my research at TUT. Professor Takeuchi purchased many chromatographic instruments, and my mentor, Professor Ishii, recommended that I start my research work on microcolumn liquid chromatography (micro-LC), which was his main topic at that time. I accepted his advice and started working on
constant, geometrical descriptors [e.g., van der Waals volume (Vw) and van der Waals surface area (Aw) and shape parameter or length-to-breadth ratio (L/B)], topological descriptors [e.g., connectivity index % and correlation factor (F)], electronic descriptors, Hammett's constant (a, HD, and HA), which are proton-donating and proton-accepting properties. By the multiregression analyses of these retention data with the above-mentioned descriptors, the most dominant properties are found by the regression coefficients. The results we have found show that the most important descriptor in re versed-phase LC separations is hydrophobicity. The next most dominant descriptors are the shape and size of the molecules for nonpolar compounds and electrical descriptors for polar compounds. This means that if one can generate some equations to describe the retention, like Eq. (1) where Pi is defined in terms of log P, n, L/B and a, we can predict retention of other solutes if Pi values for those compounds are known.
