Application of ICP sector field MS and principal component analysis for studying interdependences among 23 trace elements in Polish beers

Twenty-three metallic elements, including almost all essential and toxic metals such as lead, cadmium, mercury, arsenic, silver, and thallium, have been quantified in 35 types of bottled and canned Polish beer by using double-focusing sector field inductively coupled plasma mass spectrometry (ICP-MS) with ultrasonic nebulization. The samples were digested using concentrated HNO3 in closed PTFE vessels and applying microwave energy under pressure. The means and medians of the concentrations of Rb, Mn, and Fe were on the order of 200 ng/mL; Cu, Zn, V, Cr, Sn, As, Ph, and Ni were detected at 1-5 ng/mL; Ag, Ga, Cd, Co, Cs, Hg, U, and Sb were found at < 1 ng/mL; and In, Tl, Bi, and Th were present at < 0.1 ng/mL. The concentrations of Hg, Cd, As, Ph, and Zn were 1-3 orders of magnitude lower than proposed tolerance limits. The interdependences among determined trace elements were examined using the principal component analysis (PCA) method. The PCA model explained 74% of the total variance. The metals tend to cluster together (As, Tl, Cs, Sn, Th, Si, and Hg; Cd and Co; Cs and Cr; Fe and Zn; Mn and V).