High-resolution continuum source quartz tube/flame atomic absorption spectrometry method with broad applicability for the comprehensive assessment of selected toxic elements content in recyclable (bio)plastic materials

Abstract

A method with broad applicability for evaluating the content of As, Sb Bi, Hg, Cd, Cu, Zn, Sr, Mn, Ni, Cr, Co and Pb was developed for the characterization of recyclable (bio)polymeric materials of various types and origins based on high-resolution continuum source atomic absorption spectrometry after high-pressure microwave-assisted wet digestion in H₂SO₄–HNO₃–H₂O₂ mixture. The limits of detection (LODs) for As, Sb Bi and Hg were in the range 0.005–0.020 mg kg⁻¹ after chemical vapour generation and quartz tube atomization, while for the other elements determined in air-acetylene flame were 0.1–1.5 mg kg⁻¹. The recoveries were in the range 95–105% with extended uncertainty of 9–21% (k = 2). Plastics of polyethylene terephthalate, polypropylene, polyethylene, epoxy resin, polyvinyl chloride and acrylonitrile butadiene styrene showed higher concentrations of the studied elements, but variable depending on the element, nature and origin of the polymeric materials. Biopolymeric or hybrid polymeric materials could represent a risk for at least one of the elements (As, Sb, Bi and Zn). The recycling of plastics from electronic products, medical activity, food and cosmetics packaging, office supplies and toys generate recyclable materials with concentrations of As, Sb, Bi, Cu and Zn higher than agriculture, domestic activities, and constructions, in which As and Sb were below the method LODs. Chromium, Co and Pb were below LOD in all samples. However, in all the (bio)polymeric recyclable materials considered in this study, the concentrations of the elements were below the limits imposed by European regulations, regardless of their origin and use. Tukey's statistical test showed both significant and not significant differences (p > 0.05) among the content of elements in materials with concentration above the LODs of the method.