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Multi-element analysis of bread, cheese, fruit and vegetables by double-focusing sector-field inductively coupled plasma mass spectrometry

Khouzam, Rola Bou, Lobinski, Ryszard, Pohl, Pawel
Analytical methods 2011 v.3 no.9 pp. 2115-2120
aluminum, antimony, arsenic, atomic absorption spectrometry, breads, cadmium, cheeses, chromium, cobalt, copper, dried milk, fruits, hydrogen peroxide, indium, ions, iron, lead, manganese, mercury, molybdenum, nickel, nitric acid, reference standards, silicon, silver, skim milk, tin, toxic substances, vanadium, vegetables, wheat flour, zinc
An analytical method using double-focusing sector-field ICP MS was developed for the routine simultaneous multi-element analysis for essential and toxic elements (Ag, Al, As, Cd, Co, Cr, Cu, Fe, Hg, In, Li, Ni, Mn, Mo, Pb, Si, Sb, Se, Sn, V and Zn) in different food samples (bread, cheese, fruit and vegetables). Samples were hot-plate digested with a mixture of concentrated HNO₃ and H₂O₂. Interfering ions involving matrix constituents were detected for several elements at the resolution of 300 (typical for a quadrupole analyzer) and could be separated at the 4000 and 10 000 resolution. The method was validated by the analysis of certified reference materials: wheat flour (NIST 1567a), non-fat milk powder (NIST 1549) and brown bread (BCR-IRMM 191). The method used in our laboratory over the period of one year for the analysis of over 300 samples showed a typical interday precision of 3–5% and intraday precision of 5–10% for virtually all the elements and investigated matrices.