Detection of sulphonamide residues by screening test for antibiotic residues (STAR) and utilisation of para-aminobenzoic acid (PABA) for presumptive identification
2007
Janošová, J., University of Veterinary Medicine, Košice (Slovak Republic) | Kožárová, I. | Máté, D. | Kovaliková, M.
The aim of the present work was to determine the sensitivity of the reference STAR method for the residue screening of 10 different standards from the sulphonamide (SA) group and to utilise the inhibitory effect of PABA as a confirmatory solution regarding the SA group for the presumptive identification of these drugs. Phtalylsulphathiazole(PHT),sulphadimidine(SD), sulphaguanidine(SG),sulphachlorpyridazine(SCHP)sulphamerazine(SRZ),sulphamethoxazole(SMX),sulphanilamid (SAM),sulphanilic acid(SAC),sulphaquinoxaline(SQ)and sulphathiazole(STZ) were tested using the concentrations from 0.05 micro g per ml to 1 micro g per ml. The detection sensitivity of STAR method represented by minimum inhibiting concentration(MIC)was 0.05 micro g per ml for SCHP, SMX, SQ and STZ, 0.1 micro g per ml for SRZ,and 0.3 micro g per ml for SD. The MICs represent the detection limit of the method (LOD). No detection sensitivity was observed for PHT, SG, SAM and SAC standards. The inhibitory effect of PABA to the residual concentrations of SA standards was evaluated after the addition of PABA to the agar medium at the concentrations of 1, 3, 10, and 20 micro g per ml. The results of examinations showed that PABA completely inhibited the antibacterial effects of all tested concentrations of SA standards already at the concentration of 1 micro g per ml. In our judgement,the presented concentration of PABA can be recommended for the confirmation of the presence of SA residues even at the concentrations, which present a potential risk to human health.
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