Objective To build a method to determine tetracyclines in drinking water by ultra high performance liquid chromatography (UPLC) coupled with solid phase extraction.
Methods Water sample (200 mL) was added to Oasis HLB solid phase extraction column at 10-15 mL/min, then eluted by methanol and ethylacetate mixture (v/v, 1:9), dried with nitrogen, and dissolved to the mark of 1.0 mL using 30% methanol solution. Then 10 μL final processed sample was injected in UPLC.
Results The standard curves for the four tetracyclines were linear over the concentration range of 0.05-1.00 mg/L, with correlation coefficients all above 0.998. The limits of detection were 0.063-0.250 μg/L. The average recoveries ranged from 77.2% to 136.0%, and the relative standard deviations were in the range of 0.88% to 5.86%. No selected tetracyclines were detected in 12 samples of treated water and tap water.
Conclusion This method has advantages of simple pre-treatment, rapid UPLC analysis, wide linear range, and low limits of detection, so it can be used to detect tetracyclines in drinking water.
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