Use of Q-ICP-MS Following Microwave-Assisted Digestion in the Determination of 40 Elements for Seafood Origin Authentication

The simultaneous determination of 40 elements (Ag, As, Ba, Cd, Co, Cr, Cu, Ga, Mn, Mo, Nb, Ni, Pb, Rb, Sb, Se, Sn, Sr, Ta, Te, Th, TI, U, V. Zn, Zr and the lanthanides Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Tm, Y, and Yb) in seafood by quadrupole inductively coupled plasma mass spectrometry (Q4CP-MS) after microwave-assisted digestion is exhaustively studied. The evaluation of different strategies to eliminate or minimize interferences was carried out in order to develop a fast and simple multi-elemental analysis method. Isotope selection, measurement mode (standard or collision cell technology), sample digestion medium (HNO3 alone or HNO3 + H2O2) and the suitability of different internal standards (Ge, Rh, In, Tb, and Re) were considered. External calibration with aqueous standards was feasible for all elements. Accuracy was demonstrated using six certified reference materials (CRMs) and through spike recovery tests. No significant differences at the 95% confidence level were observed. Precision, calculated as relative standard deviation from four independent digestions, was in the 1-11% range for all cases. With this methodology, 158 mussel samples from Galicia (Northwest of Spain) with Protected Designation of Origin (PDO) were analyzed for authentication purposes.