Proposition of electronic waste as a reference material - Part 2: homogeneity, stability, characterization, and uncertainties
In many cases involving the technological materials management, such as electronic waste, a characterization is therefore to determine the precise elemental composition, as well as detect harmful elements and substances. However, its measures are hampered by the lack of suitable reference materials for electronic waste. In the present study is discussed a newly developed reference material of electronic waste according the ISO Guides 30-35 requirements. The evaluation of homogeneity, stability and characterization studies were performed using microwave-assisted acid leaching (aqua regia 50% v/v) and inductively coupled plasma optical emission spectrometry (ICP OES) for determination of Ag, Al, As, Au, Ba, Cr, Cu, Fe, Ni, Pb, Sb, Si, Sn, and Zn. One-way analysis of variance (ANOVA) with 95% confidence level and linear regression were used as statistical parameters to obtain the uncertainty contributions to characterization (uchar), between-bottle homogeneity (ubb), short-term (usts) and long-term (ults) stability tests. The results from the collaborative trial allowed obtain the estimated mass fraction and associated uncertainty (URM) for each element monitored.