Investigating the origin of tomatoes and triple concentrated tomato pastes through multielement determination by inductively coupled plasma mass spectrometry and statistical analysis.

The concentration of 32 elements (Al, As, Ba, Be, Ca, Cd, Ce, Cu, Dy, Fe, K, La, Lu, Mg, Mn, Na, Nd, Pb, Rb, Sm, Sr, Th, U, V, Zn) was determined in tomatoes harvested in different four Italian regions and in triple concentrated tomato paste samples coming from Italy, China, Greece and California. The resulting multielement profiles were processed using three chemometric techniques to evaluate the possibility of discrimination between different cultivation areas. The closed-vessel microwave digested samples were diluted and analyzed by DRC-ICP-MS with CH(4) as reaction gas. The accuracy of the proposed method was considered acceptable (values in the range 75-120%) for 25 out of the 35 elements of the reference material NCS ZC85006 Tomato. The origin of tomato fruits and the areas of production as "Italy" and "non-Italy" of the triple concentrated pastes were evaluated by three supervised pattern recognition procedures, linear discriminant analysis (LDA), soft independent modeling of class analogy (SIMCA) and K-nearest neighbors (KNN).