Phenoxyacetic acids, development from

Statistical and computational methods have been used to quantify structure-activi relationships leading to quantitative structure-activity relationships (QSAR). The concqpt of QSAR can be dated back to the work of Crum, Brown and Fraser from 1868 to 1869, and Richardson, also in 1869. Many notable papers were published in the period leading up to the twentieth century by men such as Berthelot and Jungfleisch in 1872, Nemst in 1891, Ov ton in 1897 and Meyer in 1899 (7). Professor Corwin Hansch is now regarded by many as the father of QSAR, because of his work in the development of new and innovative techniques for QSAR. He and his co-woikers produced a paper that was to be known as the birtii of QSAR, and was oititled "Correlation of biological activity of phenoxyacetic acids with Hammett substituent constants and partition coefficients" (2). 

Cserhdti and Forgacs [807] studied the retention of phenoxyacetic acid and a series of 10 mono-, di, and trichlorinated analogs on a porous graphitized carbon (PGC) colunm (2 = 230 run). The capacity factors for these compounds were determined using isocratic mobile phases of dioxane/water ranging from 30% to 85% dioxane (in 5% increments). A linear relationship between log k and percent dioxane in the mobile phase was generated and is useful for potential method development. Peak shapes were improved through the addition of 50 mM acetic acid to the mobile phase (which protonated the acids). The same authors [808] studied the... 

New layers have been studied and introduced for the separation of 30 organic acids. For example, phenoxyacetic acid herbicide was separated from cinnamic, citric, gallic, maleic, oxalic acid, etc., on a calcium sulfate layer containing /r-dimethyl-aminobenzaldehyde and developed with distilled water (87) (Table 7). 

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