Rapid screening of illegally added poppy husk in hot pot sauce and soup by thermal desorption electrospray ionization-triple quadruple mass spectrometry

Abstract

A thermal desorption electrospray ionization-triple quadruple mass spectrometry (TD-ESI-MS/MS) method was developed for the rapid screening of poppy husk in hot pot sauce and soup. The solid surface or liquid sample was directly touched by a simple metal probe. The analytes collected on the probe were desorbed and ionized using a TD-ESI source, after which the analyte ions were detected by MS/MS in multiple reaction monitoring (MRM) mode. The results were compared with those of colloidal gold card rapid detection and verified by high performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-MS/MS). The instrument gave the best response with the highest sensitivity under the following conditions: thermal desorption temperature, 260 ℃; injection solvent, 0.1% formic acid aqueous solution containing 10 mmol/L formic ammonium-acetonitrile (1:1, v/v); flow rate, 200 μL/h. The limits of detection (LODs) for papaverine, noscapine, and thebaine in five alkaloids were 2 μg/kg, while those for codeine and morphine were 10 μg/kg in hot pot sauce and 5 μg/kg in soup. The sensitivity of this method was significantly superior to that of the colloidal gold card rapid detection. The method was applied to 50 batches of hot pot sauce and soup. Noscapine, papaverine, thebaine, and morphine were detected in a positive sample of chicken soup, which was consistent with the result of the HPLC-MS/MS method. This method without sample preparation and chromatographic separation is fast, green, and environmentally benign, thus being suitable for the rapid qualitative analysis of poppy husk in food.