Abstract

Systematic errors observed when using inductively coupled plasma atomic emission spectrometry (ICP-AES) and mass spectrometry (ICP-MS) for the multi-element determination in acid digests of environmental samples (tea leaves) were evaluated. Two chemometric approaches, experimental design and principal component analysis, were used in order to establish the errors associated with each stage of the analytical method: sample digestion (effect of the “number of acid digestions”) and measurement step (effect of the “number of replicates” and the “calibration”). The elements under study were Co, Cr, Cs, Cu, Ni, Pb, Rb and Ti by ICP-MS, and Ba, Ca, Fe, Mg, Mn, Sr and Zn by ICP-MS and ICP-AES. Flame atomic absorption spectrometry was used for comparative purposes. A Chinese tea certified reference material with certified concentration for most of the elements was employed as the sample matrix. Variance estimation was made from ANOVA outputs from a full factorial design (FFD) 4¹ × 4¹ × 2¹.