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Page No. : 61-67

ABSTRACT

Low levels of antibiotic residues occur in sediment samples. Detection of such levels in complex matrices will depend on the type of extraction methods used. In the present study modifi ed QuEchERS method was optimized and compared with other conventional and some published QuEchERS extraction methods to determine simultaneous extraction and quantifi cation of commonly used multiple antibiotics of tetracycline, fl uoroquinolone and sulfonamide groups. The mixture of MeOH: ACN: 0.1 M EDTA-McIlvaine buff er (12.5/37.5/50) was selected as an extraction buff er to get maximum recovery from the sediment samples in the study. The performance of analytical methods was validated through an estimation of the specifi city, linearity, trueness, intra-day and inter-day and precision. Antibiotic-free sediment samples were spiked at diff erent concentration levels and analyzed by the optimized HPLC method. The results revealed that the linear regression coeffi cient obtained for the selected antibiotics in analytical method I, II & III were from the ranges 0.986-0.996, 0.994-0.996 & 0.972-0.988, respectively. The recoveries obtained in analytical method II (modifi ed QuEchERS method) ranged from 84 to 95% to the selected antibiotics and LOD, LOQ values were ranged from 5.31-8.0 ng/g and 16.10-24.0 ng/g, respectively, whereas, LOD and LOQ values for analytical method I & III were comparatively high with low recoveries for tetracycline group of antibiotics were observed. The analytical method II also resulted in good precision and relative standard deviation (<10%) for intraday assay and (< 17%) inter-day assay when compared with analytical method I & III. Finally, analytical method II was successfully applied for analyses of antibiotics in sediment samples of aquatic community ponds. The results indicated that a total of seven sediment samples were found positive for all three groups of antibiotic residues and a higher mean concentration of OTC was detected.
Keywords: Antibiotics, HPLC method, QuEchERS, sediment