A Real-time Metabolomic Profiling Approach to Identify Virgin Olive Oil Adulteration by Rapid Evaporative Ionization Mass Spectrometry

The new trend of adulteration detection of virgin olive oil (VOO) is exploiting a rapid, real-time analytical method to make on-site screening possible. Therefore, the main objective of this work is to develop an analytical method capable of detection and quantifying adulteration of VOO by combining the rapid evaporative ionization mass spectrometry (REIMS) with multivariate statistical analysis. With the sampling by electric soldering iron, this method can effectively distinguish VOO from other plant oils (blended olive oil, sunflower oil, peanut oil, colza oil, corn oil, and soybean oil) with an accuracy of 99.29%. Moreover, principal component analysis-linear discriminate analysis (PCA-LDA) shows that the method is able to identify the adulterated VOO with other oils in different levels. The quantitative prediction models were established using partial least squares (PLS) for the adulteration of VOO with four types of different oils. High correlation coefficients above than 0.97 were achieved in an approximated linear relationship. The result indicates that REIMS combined with appropriate multivariate statistics can be used for VOO adulteration analysis with detection limits as low as 5%.This method could serve as a rapid and real-time approach for authentication and adulteration analysis of VOO. This is also the first application of REIMS coupled with electric soldering iron as sampling tool in the analysis of plant oil samples without the assistance of any additional ionizing medium.