Monitoring the authenticity of organic rice via chemometric analysis of elemental data

• Rice discrimination was based on 20 chemical elements determined via ICP-MS.
• Organic and ordinary rice samples were separated with the aid of exploratory techniques (PCA and HCA).
• Authenticity of organic rice samples was verified with the aid of classification techniques (SIMCA and KNN).

50 rice samples (18 organic and 32 ordinary) from Brazil were analyzed with inductively coupled plasma mass spectrometry (ICP-MS) for 20 elements (As, B, Ba, Ca, Cd, Ce, Co, Cr, Cu, Fe, K, La, Mg, Mn, Mo, P, Pb, Rb, Se and Zn) to identify significant differences between the two types (organic and ordinary) of rice. Concentrations of As, B, Ba, Co, Cr, Cu, Mn, P and Zn were found to be higher in ordinary versus organic rice, while K, Ca, Mo, Rb and Se concentrations were lower in ordinary versus organic samples. The remaining investigated elements (Cd, Ce, Fe, La, Mg and Pb) exhibited statistically equivalent concentration in the two types of rice. Principal Component Analysis (PCA), Soft Independent Modeling of Class Analogy (SIMCA), Hierarchical Cluster Analysis (HCA) and K-nearest neighbors (KNN) statistical techniques of the elemental fingerprints were readily able to discriminate organic from ordinary samples and can be used as alternative methods for adulteration evaluation.