Simultaneous extraction of antibiotic and estrogen from animal blood serum using aqueous two-phase systems as predictor of environmental impact.

Efficient analytical methods are required for optimizing dosage of veterinary antibiotics and hormones in order to reduce toxicity and antimicrobial resistance in the environment. Thus, the objective of this work was to develop a rapid and low-cost method for determination of hormone estradiol and antibiotic chlortetracycline in bovine and porcine blood serum by aqueous two-phase system (ATPS) extraction and capillary electrophoresis quantification. ATPS based on ionic liquid cholinium alaninate and citrate salt along with mixtures of protic and aprotic polar solvents were evaluated in terms of recovery of extraction (%R). The liquid-liquid equilibrium, phase diagrams, and tie lines are discussed. Antibiotic migrated to solvent-rich phase (R ≈ 89.0%) to all systems. Estradiol migrates to ionic liquid-rich phase; however, addition of 10% methanol changed partition to solvent-rich phase (R ≈ 89.7%). The method has high recovery and cleanliness, is cost-efficient, scalable, and hence is adequate for screening of antibiotics and hormones tested in animal blood serum for dosage optimization and to predict their environment.

Simultaneous quantification of antibiotics in wastewater from pig farms by capillary electrophoresis.

Pig farming is an important activity in the economic development of Mexico with millions of tons of meat produced annually. Antibiotics are used in therapeutic dose to prevent diseases, and sometimes as growth promoters. These compounds are not completely metabolized; they are carried into the environment in its active form at concentrations that could induce antibiotic resistance in bacteria, which could be transferred to human pathogens by horizontal gene transfer. The objective of this work was to develop methods of analysis for simultaneous quantification of the antibiotics Oxytetracycline (OXT), Chlortetracycline (CLT), Enrofloxacin (ENRO) and Ciprofloxacin (CIPRO) by field-amplified sampling injection in capillary zone electrophoresis (FASI-CZE). The method was validated by parameters of (1) linearity, obtaining a lineal range of 0.05 at 1 µg mL-1 for ENRO and CIPRO, and from 0.1 to 1 µg mL-1 for OXT and CLT; (2) precision, obtaining values <5% of standard deviation for CIPRO and ENRO and <10% of standard deviation for OXT and CLT; (3) accuracy, with recovery values from 93 to 115%; (4) selectivity, with values of resolution >2 for the all antibiotics tested. To prove the method, a sample of wastewater from a local pig farm was analyzed, detecting a concentration of 0.140 ±â€¯0.009 for OXT. This concentration was higher than the minimal selective concentration, indicating the point in which resistance to a determined antibiotic could develop. The methods were validated with precision and sensitivity comparable to chromatographic methods, which can be used to analyze wastewater from pig farms directly.