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: 5.0×10−6–3.2×10−3 M sulfamerazine, 5.0×10−6–3.2×10−3 M sulfadiazine, 7.5×10−7–3.2×10−4 M sulfasalazine, 9.0×10−7–5.0×10−4 M sulfamethazine, 6.5×10−8–3.5.0×10−5 M sulfamethoxazole, 9.7×10−8–5.0×10−5 M sulfathiazole, and 9.0×10−8–3.2×10−5 M 5-sulfaminouracil. Detection limits were calculated as: 3.9×10−6 M for sulfamerazine; 4.0×10−6 M sulfadiazine; 2.5×10−7 M sulfasalazine; 3.7×10−7 M sulfamethazine; 4.0×10−8 M sulfamethoxazole; 6.4×10−8 M sulfathiazole and 6.0×10−9 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.