Chaos Entropy Index Combined with Desorption Atmospheric Pressure Chemical Ionization Mass Spectrometry for Rapid Analysis of Complex Viscous Sample, Edible Oil

By means of surface desorption atmospheric pressure chemical ionization mass spectrometry (DAPCI-MS), mass-spectra fingerprints of various oil samples were rapidly recorded in the mass range of m/z 50-1000 without any sample pretreatment in negative ion mode. A new spectrogram analysis method (Chaos Entropy Index) for identifying complex mixtures was established and applied to the authentication of expired oil. Multivariate statistics analysis showed that expired edible oils can be successfully separated from fresh edible oils with 100% accuracy on the basis of Global CEIs and the most significant mass ranges presenting major feature peaks of expired oil were determined based on Local CEIs. These experimental findings demonstrate that as a rapid, simple, and accurate analytical method, CEI approach in conjunction with DAPCI-MS has an extensive prospect for differential analysis of complex viscous mixtures.