Pulsed electrochemical detection of sulfur-containing antibiotics

Sulfur-containing antibiotics are routinely used in both human and veterinary medicine for the treatment of bacterial infections. These compounds are also used in veterinary medicine for growth promotion, as well as for the prevention and treatment of bacterial bee diseases. If proper withdrawal times are not observed, food derived from these animals may be contaminated with residual amounts of antibiotics. The improper and illegal use of drugs will also often result in antibiotic residues in food. The presence of such residues in food is of toxicological and regulatory concern as these may cause allergic hypersensitivity reactions, and may also pose antibiotic resistance in humans.;This research takes advantage of electrochemical detection (ECD), known for its inherent sensitivity and selectivity for electroactive compounds, for the determination of sulfur-containing antibiotics. Pulsed electrochemical detection (PED) with integrated pulsed amperometric detection (IPAD) waveform will be applied here; PED is sensitive, selective, and direct. Cyclic voltammetry (CV) was utilized to optimize the IPAD waveform parameters and to study the electrochemical properties of sulfur-containing antibiotics, as well as primary aromatic amines (PAAs).;The developed waveform was applied for the quantitative determination of sulfonamides (SAs) in pharmaceutical formulations. Results obtained from the PED method were compared to those obtained using UV detection for the quantitative analysis of sulfa drugs in pharmaceutical formulations. HPLC-PED was found to be a valid method for the determination of sulfa drugs in pharmaceutical formulations. The developed waveform was also applied for the determination of sulfathiazole (STZ) and lincomycin in honey. HPLC-PED was found to be a valid method for sensitive and selective determination of the antibiotics in honey. Sample pretreatment was achieved by solid-phase extraction (SPE) using OASIS HLB cartridges. The method detection limits were determined to be 30 mug˙kg-1 and 160 mug˙kg-1 for STZ and lincomycin, respectively. The high sensitivity and selectivity of PED for sulfa drugs and lincomycin reduces sample preparation and produces simpler chromatograms in complex matrices when compared to UV detection. IPAD provides an alternative means of detection for the determination of sulfur-containing antibiotics, many of which have poor chromophoric properties.