Quaternary ammonium salt substance detection method

The invention provides a quaternary ammonium salt substance detection method, which comprises: 1) sample pretreatment: weighing a sample, placing in a glass colorimetric tube, adding a methanol solution of 0.5% formic acid to achieve a constant volume, carrying out ultrasonic extraction, centrifuging, and filtering to obtain a filtrate as a sample liquid to be detected; 2) preparing a standard solution; (3) detection: injecting the solution to be detected obtained in the step (1) or (2) into a high performance liquid chromatography-tandem mass spectrometry system for analysis by adopting the modes of partial sample injection, gradient elution and multi-reaction monitoring, obtaining parent ions through first-stage mass spectrometry scanning, and selecting target characteristic ion pairs through second-stage mass spectrometry scanning for qualitative and quantitative analysis; 4) establishing a standard curve; and 5) obtaining qualitative and quantitative results of the quaternary ammonium salt in the sample.