Chloramphenicol (CAP; C 11 H 12 Cl 2 N 2 O 5 ; Figure 1) is a broadspectrum antibiotic having activity against both gram-positive and gram-negative bacteria and is effective in the treatment of several infectious diseases in animals all over the world, including food-producing animals because of low cost, great pharmacokinetics properties (Zhiming et al., 2015), remarkable penetration into the tissues, and ready availability (Rønning et al., 2006). However, CAP is, in certain susceptible individuals, associated with harmful

not available Dhaka Univ. J. Sci. 65(1): 83-84, 2017 (January)

Antibiotics residue of any drug above the allowable limit in poultry and cattle farms reduces food safety and quality. The main aim of this study was to develop and validate a sensitive and reproducible method to assess the amount of residual limit of antibiotics. Poultry meat and beef samples were analyzed for the presence of six sulfa drugs i.e., sulfathiazole (STZ), sulfadiazine (SDZ), sulfamerazine (SMZ), sulfamethazine (SMT), sulfamethoxypyridazine (SMP) and sulfadimethoxine (SMX) by LC-MS/MS coupled with ESI and QQQ mass analyzer. Identification and quantification of drugs were carried out by SCAN and MRM methods. Matrix matched calibration curves were linear with correlation coefficients (r2) 0.997, 0.998, 0.997, 0.993, 0.996 and 0.998 for six drugs, respectively. The method was validated by recovery experiments at 2 spiking levels (5 & 10 ng/mL). Extraction was done by QuEChERS method, cleaned up was carried out with C-18 powder & PSA followed by analysis using LC-MS/MS. Intra- and inter-day experiments were done with desirable accuracy and precision, and recoveries were in the range of 86-104%. Poultry meat (n=30) and beef samples (n=30) were analyzed from thirty different markets, super shops, and residues of six sulfa drugs were found below the detection limit.