MILK SAMPLES CLASSIFICATION ESTABLISH ON THEIR ELEMENTAL COMPOSITION. DETERMINATION BY INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY AFTER SINGLE-STEP SOLUBILIZATION WITH N,N-DIMETHYLFORMAMIDE.

MARIANELA SAVIO; AZCARATE, S.M.; PATRICIA SMICHOWSKI; JOSÉ M. CAMINA; LUIS D. MARTINEZ; RAUL GIL

Mérida

Simposio; 13th Rio Symposium on Atomic Spectrometry; 2014

A single-step procedure for trace elemental analysis of milk samples is presented. Solubilization with dymethylformamide (DMF) was assayed prior to inductively coupled plasma mass spectrometry (ICPMS) detection with a high efficiency sample introduction system. Small amounts of DMF were used with soft heating and dilution with ultrapure water, resulting in high elemental concentrations due to low dilution factors. All main instrumental conditions were optimized in order to readily introduce the samples without matrix elimination. In order to assess and mitigate matrix effects in the determination of As, Cd, Co, Cu, Eu, Ga, Gd, Ge, Mn, Mo, Nb, Nd, Ni, Pb, Pr, Rb, Sm, S, Sr, Ta, Tb, V, Zn, and Zr, matrix matching calibration with 103Rh+ as internal standard (IS) was performed. The obtained limits of detection were between 0.68 (Tb) and 30 (Zn) g L−1. For accuracy verification, certified Skim milk powder reference material (BCR 063R) was employed. The developed method was applied to trace elemental analysis of milks commercially available. Principal components analysis was used to correlate the content of trace metals with the kind of milk, obtaining a classification according to adults, baby or baby fortified milks. This is a simple and fast approach for quality control, traceability and routine analysis of milks.