We developed a QuEChERS (quick, easy, cheap, effective, rugged and safe) method for
the high through-put determination of 28 common veterinary antibiotics in swine wastewater
using one-step dispersive solid-phase extraction (d-SPE) for sample cleanup and ultra-performance
liquid chromatography-tandem mass spectrometry for detection. The orthogonal test
method was used to systematically investigate the parameters that might influence
d-SPE efficiency. The optimal d-SPE procedure utilized 40 mg primary secondary amine
sorbent and 3 g L-1 Na2EDTA. The recoveries ranged from 50 to 100% with relative standard
deviations <20% for all target analytes except for enrofloxacin and chlortetracycline.
The limits of detection and limits of quantification for all the analytes ranged from
0.002 to 0.200 ng mL-1 and 0.005-0.500 ng mL-1, respectively. The developed method
was successfully applied to the analysis of 28 antibiotic residues in swine wastewater
from 10 pig farms located in central China. Fourteen antibiotics including 4 sulfonamides
(sulfadiazine, sulfamerazine, sulfamonomethoxine and trimethoprim), 5 fluoroquinolones
(norfloxacin, ciprofloxacin, pefloxacin, enrofloxacin, and ofloxacin), 1 lincosamide
(lincomycin) and 4 tetracyclines (doxycycline, tetracycline, oxytetracycline, and
chlortetracycline) were detected at levels ranging from 0.0560 to 1793 ng mL-1. Our
results demonstrated that the optimized method is a simple but reliable analytical
technique for the routine monitoring of veterinary antibiotics in swine wastewater.
Swine wastewater samples that we analyzed from 10 pig farms in Jiangxi Province, China
were highly contaminated and pose a serious threat to ecosystems and to public health.