Determination of Six Chemicals Illegally Added in Hot Pot Soup by QuEChERS Combined with UPLC-MS/MS

A method for the determination of six analgesic-antipyretic drugs (paracetamol, chlorpheniramine maleate, diclofenac sodium, aspirin, aminophenazone and antipyrine) illegally added in hot pot soup by QuEChERS combined ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established. The hot pot soup samples were extracted with 0.1% formic acid in acetonitrile followed by a salting-out step with anhydrous MgSO₄ and CH₃COONa. After centrifugation, the supernatant was cleaned up with 100 mg of PSA, 100 mg of C₁₈ and 50 mg of GCB. The separation was performed on a Waters C₁₈ column (50 mm×2.1 mm, 1.7 μm) by gradient elution acetonitrile with and water containing 0.1% formic acid. The electrospray ionization mass spectrometry was operated in the positive and negative mode using multiple reaction monitoring (MRM). The target compounds were quantified by external standard method. Under the optimal conditions, the calibration curves of the six chemicals were linear in the concentration range of 1.0~200 ng/mL (aspirin 10.0~2000 ng/mL) with correlation coefficients larger than 0.99. The limits of detection (LOD) ranged from 0.05~1.0 μg/kg. The average recoveries for hot pot soup at three spiked levels ranged from 72.1%~114.8% with relative standard deviations (RSDs) of 0.81%~14.6%. The method was suitable for the simultaneous detection of 6 illegally added chemicals in hot pot soup with its rapidity, high accuracy and high precision.