Thin-layer Chromatographic Method for Quantification of Sulfonamides in Chicken Meat

The sulfonamides are a widely used group of antimicrobials in veterinary practice especially in developing countries due to their broad spectrum of activity, availability, and low cost. The objective of this study was to establish a thin-layer chromatographic (TLC) method to detect residues of commonly used sulfonamides in Sri Lanka in chicken. The TLC method separated sulfadiazine (SDZ), sulfadoxine (SD), sulfamethazine (SMZ), sulfathiazole (STZ), and sulfaquinoxaline (SQ) on silica gel plates using chloroform: n_butanol (90:10). Sulfonamides densitometric measurements were conducted by derivatising with fluorescamine and scanning the separated bands at 366 nm. The quantity of the sulfonamide in samples was calculated using a standard calibration curve obtained by plotting values of peak area against sulfonamide concentrations at 200, 150, 100, 50, 30, and 25 ng/g. The mean percentage recoveries were 80–120% while the intra-day and inter-day precision was 3–22% and 6–42% respectively. The SD had the highest limit of detection (LOD) and limit of quantification (LOQ) values of 60 and 100 ng/g respectively. The LOD of all the other analytes were 40 ng/g, and STZ had the lowest LOQ values of 50 ng/g. A reliable, inexpensive, simple, liquid-liquid extraction method for the rapid analysis of five sulfonamides at maximum residue limit (MRL) in chicken using TLC was developed.