¹ H NMR adulteration study of hempseed oil with full chemometric approach on large variable data

Adulteration of hempseed (H) oil, a well known health beneficial nutrient, is studied in this work by means of ¹ H NMR spectroscopy. H oil samples were mixed with cheap and widely used oils such as rapeseed (R) oil and sezame (Se) and sunflower (Su) oil. Many samples of different geographic origins were taken into account. Binary mixture sets of hempseed oil with these three oils (HR, HSe and HSu) were considered. ¹ H NMR spectra of pure oils and their mixtures were recorded and quantitative analyses were performed using Partial Least Squares Regression (PLS), First-Break Forward Interval PLS methods (FB-FiPLS) and Interval Ridge Regression (iRR). The obtained results show that each particular oil can be very successfully quantified (RMSEP 1.4–3.0%), and that NMR coupled with iRR has a great potential in studying signals of low intensity belonging to oil microconstituents. This means that ¹ H NMR spectroscopy coupled with multivariate methods can rapidly and effectively determine both the fatty acid profile and the level of adulteration in the adulterated hempseed oil for these studied and frequently used adulterant oils.