Abstract: A HPLC method with UV detection was proposed to determine the concentration of 3-phenoxybenzoic acid (3-PBA) in microbial degradation systems. The chromatographic separation was performed on a Gemini 100A C18 column (5.0μm, 150 mm × 4.60 mm, i.d.) using a mobile phase made up of acetonitrile and water (70:30, V/V) at a flow rate of 0.7 mL/min, and 3-PBA was detected at 210 nm using a UV detector. The retention time of 3-PBA was 4.268 min. The linear range of the method was 0.5－50.0 mg/L. The average spike recovery for 3-PBA was 98.919%, with a relative standard deviation (RSD) of 2.78%. The residues of 3-PBA in 4 different microbial degradation systems were 24.467, 86.266, 2.633 mg/L and 1.921 mg/L, respectively. The developed method demonstrated the benefits of simplicity, rapidity, high accuracy and good separation.

Key words: HPLC-UV, 3-phenoxybenzoic acid, microbial degradation system, determination