Determination of pKa values of some sulfonamides by LC and LC-PDA methods in acetonitrile-water binary mixtures

The dissociation constants of seven sulfonamide antibiotics, sulfadiazine, sulfathiazole, sulfamerazine, sulfamethazine, sulfamonomethoxine, sulfadoxine and sulfamethoxazole, have been determined in different acetonitrile-water binary mixtures (15, 30, 40, 50% v/v) by means of reversed-phase liquid...

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Bibliographic Details
Published in:Journal of the Brazilian Chemical Society 2010, Vol.21 (10), p.1952-1960
Main Authors: Şanli, Nurullah, Şanli, Senem, Özkan, Güleren, Denizlic, Adil
Format: Article
Language:eng ; por
Subjects:
CHEMISTRY, MULTIDISCIPLINARY
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Summary:The dissociation constants of seven sulfonamide antibiotics, sulfadiazine, sulfathiazole, sulfamerazine, sulfamethazine, sulfamonomethoxine, sulfadoxine and sulfamethoxazole, have been determined in different acetonitrile-water binary mixtures (15, 30, 40, 50% v/v) by means of reversed-phase liquid chromatographic data. Also, a method based on the absorbance spectra at the maximum of chromatographic peaks previously obtained has been applied to determine the pKa values. This method can be applied to data obtained from LC-UV (photodiode array detection (PDA)) instruments and retains all the advantages of LC and spectrophotometric methods. Linear relationships were observed when the calculated pKa values of sulfonamides in different solvent mixtures were plotted against the acetonitrile molar fraction.
ISSN:1678-4790
DOI:10.1590/S0103-50532010001000022