Rapid identification of high-viscosity rice soup quality using neutral desorption extractive electrospray ionization mass spectrometry

High-viscosity rice soup is not only a popular food item but also a traditional Chinese medicinal remedy. Herein, we developed a high-throughput characterization platform for high-viscosity rice soup analysis using Neutral Desorption Extractive Electrospray Ionization Mass Spectrometry (ND-EESI-MS) with untargeted metabolomics. The chemical fingerprint of high-viscosity rice soup was directly analyzed by ND-EESI-MS, with exogenous (<i>e.g.</i>, heavy metals and pesticides) and endogenous pollutants detected <i>via</i> qualitative and quantitative tandem mass spectrometry. Multivariate statistical analysis was then applied to distinguish the quality of the high-viscosity rice soup effectively. The concentrations of heavy metals and pesticide residues in high-viscosity rice soup were quantified, demonstrating a strong linear relationship (<i>R</i>² > 0.99) across the 0.05-2000.00 ng mL^-1 concentration range. The limits of detection (LOD) ranged from 0.27 ng mL^-1 to 2.18 ng mL^-1, while the limits of quantification (LOQ) ranged from 0.82 ng mL^-1 to 6.61 ng mL^-1. Furthermore, three specific compounds-3-methyl-2-butenoic acid, salicylic acid, and rhamnose-were quantified. These compounds demonstrated excellent linearity (<i>R</i>² > 0.99) within the linear range of 1.10-1500.00 ng mL^-1. The LOD ranged from 0.56 to 1.30 ng mL^-1, and the LOQ ranged from 1.71 to 3.95 ng mL^-1. Owing to its capability for simultaneous detection of exogenous and endogenous contaminants in complex viscous matrices, this ND-EESI-MS platform demonstrated significant potential to enhance quality control in food safety surveillance and pharmaceutical manufacturing.