Determination of Cd, Pb and Zn in Polymers by Laser Ablation Microwave Induced Plasma Optical Emission Spectrometry

The potential of laser ablation microwave induced plasma optical emission spectrometry (LA-MIP OES) for the analysis of plastic materials has been investigated. Inorganic species, e.g., metals may be added to them as additives, anti-oxidising agents, stabilisers, plasticisers, colorants and catalytic residues, contaminants and may be present in a wide range of concentrations. The study revealed elevated content of trace elements (Cd, Pb and Zn) which are components of poly(vinyl chloride) (PVC) and polyethylene (PE). Laser ablation using wavelengths of 266 nm as a sampling method for MIP OES was used. The result achieved using elaborated system were compared with those obtained after polymer samples decomposition in high pressure-temperature focused microwave heating digestion system and standard sample pneumatic nebulisation (PN) to MIP OES spectrometer. The calibration strategy using cellulose pellets as support for qualitative analysis for element determination in polymers by LA-MIP OES was proposed. This analytical performance of the LA-MIP OES system was characterised by a determination of the limits of detection (LODs) and precision (RSDs) for elements tested. The experimental concentration detection limits for simultaneous determination, calculated as the concentration giving a signal equal to three times of the standard deviation of the blank (LOD, 3σblank criterion, peak height) were 2 µg g^–1, 3 µg g^–1 and 5 µg g^–1 for Cd, Pb and Zn, respectively. The method offers relatively good precision (RSD ranged from 3 % to 5 %) for micro sampling analysis.