Determination of Benzoic Acid and Hippuric Acid Residues in Meat and Offal by Ultra-high Performance Liquid Chromatography-Tandem Mass Spectrometry

An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination of benzoic acid and hippuric acid in meat and offal. Through spiked recovery tests, methanol was selected as the extraction solvent. The extract was purified on a PRiME HLB solid phase extraction (SPE) column, detected in the multi-reaction monitoring (MRM) mode, and quantified by an external standard method. The results showed that good linearity was observed for benzoic acid and hippuric acid within the concentration range of 20–1000 and 4–200 ng/mL with correlation coefficients of greater than 0.99, and the detection limits 12.5 and 2.5 μg/kg, respectively. The limits of quantification for benzoic acid and hippuric acid were 50 and 10 μg/kg, respectively; the recoveries at three spiked concentration levels were between 70.5% and 99.7%, and the relative standard deviations (RSDs) of precision were 0.3%–7.1% (n = 6). The proposed method had good repeatability and intra- and inter-day stability, with RSDs equal to or less than 7.2%. Therefore, this method is simple, accurate and sensitive, and has a good recovery rate. It can provide technical support for the supervision of benzoic acid and hippuric acid residues in meat and offal.