engleski

TLC-efficient screening method for monitoring of veterinary pharmaceuticals waste water

Veterinary drugs are continually being released in the environment mainly as a result of manufacturing processes, disposal of unused or expired products, and excreta. Because of their physical and chemical properties, many of these substances or their bioactive metabolites end up in soils, sediments and water, where they can accumulate and induce adverse effects in terrestrial or aquatic organisms. Antibiotics analysis in water has mainly been carried out by gas (GC) or high-performance liquid chromatography (HPLC), usually in combination with mass spectrometric (MS) detection. In this work thin-layer chromatography (TLC) is presented as simple and efficient screening chromatographic method. A SPE-TLC method for simultaneous identification and quantification of seven pharmaceuticals in spiked water samples was optimized and validated. The studied compounds were enrofloxacine (ENRO), oxytetracycline (OTC), trimethoprim (TMP), sulfadimidine, sulfadiazine, sulfaguanidine and penicillin G/procaine (PGP). The method involves solid phase extraction on HLB cartridges and TLC analysis of extracts on CN modified chromatographic plates. Identification and quantification were based on RF-values and peak area, respectively. Optimization was performed by systematic variation of the mobile phase composition using genetic algorithm approach. 0.05 M H2C2O4:methanol=0.80:0.20 (v/v) was found to be optimum mobile phase composition. The following criteria were used to validate the method: selectivity, linearity, limits of detection and quantification, precision and recovery. Linearity was demonstrated in the ranges from 0.75 ng/spot to 7.5 ng/spot for ENRO, 50-250 ng/spot for OTC, 75-300 ng/spot for TMP, 150-550 ng/spot for sulfaguanidine and 50-200 ng/spot for sulfadimidine, sulfadiazine and PGP with coefficients of determination higher then 0.99. Mean recoveries ranged from 74.6% to 117.1% over the linear range. Only sulfaguanidine showed lower results. Precision was evaluated under repeatability conditions over the linear range at three different concentration levels with relative standard deviations from 0.5% to 13.1%. The results of the validation process demonstrated the method suitability for use in waste water analysis.

veterinary drugs; water; thin-layer chromatography (TLC); solid-phase extraction (SPE); optimization

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