Solid Phase Extraction-Hydrophilic Interaction Chromatographic Determination of Tetracycline Antibiotics in Wastewater
A novel method for the determination of tetracycline antibiotics(TCs),i.e.oxytetracycline(OTC),tetracycline(TC),chlortetracycline(CTC) and doxycycline(DC) in wastewater sample by hydrophilic interaction chromatography(HILIC) using amino-silica column with highly polar organic-aqueous buffer as mobile phase has been developed.TCs were collected and purified from wastewater using Oasis HLB cartridges.Separation parameters such as the buffer pH,buffer ionic strength,organic modifier concentration and flow rate have been optimized.The optimal mobile phase was 85%(V/V) acetonitrile in 6.7 mmol/L ammonium citrate buffer(pH 4.0).The developed method had good linearity(r0.999) and reproducibility(RSD1.0% for the peak area).The limits of detection for the TCs tested were between 12-30 μg/L(S/N=3).Recoveries of TCs at the concentration of 0.5-10 μg/L ranged from 90.6% to 106.5% with RSD 2.5%-6.2%.The proposed method is simple,accurate and the mobile phase is compatible for mass spectrometry due to its low ionic strength.It has been applied to the determination of TCs in abattoir wastewater samples with satisfactory results.