Potential of X-Ray Spectrometry and Chemometrics to Discriminate Organic from Conventional Grown Agricultural Products

Summary

This work describes an innovative analytical method based on X-ray spectrometry combined with chemometrics which presents high potential to discriminate conventional from organic grown tomatoes and coffee beans. This novelty is based on the irradiation of samples in a bench-top EDXRF equipment provided with a Rh tube and further treatment of the spectral data using Principal Component Analysis (PCA). Multivariate analysis results showed a tendency in separating the samples according to the production mode (organic or conventional). Regarding the spectra obtained, the K alpha peak of potassium showed to be the most responsible for discriminating different categories of samples. The chlorine K-alpha peak presented high capability in discriminating tomato and coffee samples from different origins. The method can be useful for food quality control to rapidly classify samples since the measurements can be done “in situ” with portable instruments. Nevertheless, it will be necessary to build robust classification models with a larger number of samples.