Structure Analysis of Unknown Compound in Lemon Juice by SPME-GC-TOFMS and msFineAnalysis AI
Introduction
Food flavor components are known to be an important element of good taste. Gas chromatography-mass spectrometry (GC-MS) is often used to analyze food flavor components. This is because food flavors are highly volatile and complex with numerous components. Electron ionization (EI) is one of the most popular ionization methods used in GC-MS. Consequently, compounds are typically identified by a mass spectral database search using EI mass spectra. Because molecular ions are often weak or absent in 70 eV EI mass spectra, identification of unknowns can be difficult by EI alone. In these cases, soft ionization (SI) can be very helpful for producing and identifying molecular ions. We had developed an integrated qualitative analysis workflow that automatically combines and interprets the information from EI and SI data1). And then in 2018, we introduced our integrated qualitative analysis software “msFineAnalysis” which uses both EI and SI data to improve compound identification for GC-MS applications. Despite the fact that msFineAnalysis was automatically able to determine the molecular formula and partial structure information from EI fragment ion formulas, the actual structural formulas still required manual analysis using chemical compositions. To address this, we then developed an automated structure analysis software package named “msFineAnalysis AI” which uses artificial intelligence (AI) to predict EI mass spectra from chemical structures2). We have used our newly-developed AI model to create a database of predicted EI mass spectra for around 100 million compounds.
In this MSTips, we report on an example of structure estimation of an unknown compound in lemon juice using msFineAnalysis AI.