Voltammetric detection of sulfonamides at a poly(3-methylthiophene) electrode

Detection of sulfonamide compounds in a mixture of standards at a poly(3-methylthiophene) coated on glassy carbon (GC) electrode is reported. The polymer, poly(3-methylthiophene), was electrochemically synthesized at a GC rotating disk-working electrode versus Ag/AgCl using cyclic voltammetry (+0.5 to +2.0 V). Square wave voltammetry (SQWV) with cathodic reduction (0 to -4.0 V) was used for the detection of seven sulfonamide compounds in a mixture. The working concentration ranges (curvilinear) established for different compounds in Britton-Robinson (BR) buffer (pH 6.26), were: 5.0 x 10(-6)-3.2 x 10(-3) M sulfamerazine, 5.0 x 10(-6)-3.2 x 10(-3) M sulfadiazine, 7.5 x 10(-7)-3.2 x 10(-4) M sulfasalazine, 9.0 X 10(-7)-5.0 X 10(-4) M sulfamethazine, 6.5 x 10(-8)-3.5.0 x 10(-5) M sulfamethoxazole, 9.7 x 10(-8)-5.0 x 10(-5) M sulfathiazole, and 9.0 x 10(-8)-3.2 x 10(-5) M 5-sulfaminouracil. Detection limits were calculated as: 3.9 x 10(-6) M for sulfamerazine; 4.0 x 10(-6) M sulfadiazine; 2.5 x 10(-7) M sulfasalazine; 3.7 x 10(-7) M sulfamethazine; 4.0 x 10(-8) M sulfamethoxazole; 6.4 x. 10(-8) M sulfathiazole and 6.0 x 10(-9) M 5-sulfaminouracil. The data suggests a potential application of the poly(3-methylthiophene) (P3MT) electrode for determination of sulfonamides in veterinary and other applications. (C) 2002 Elsevier Science B.V. All rights reserved.