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.
Poznanie niejednorodności, składu morfologicznego oraz mineralnego i chemicznego mikrocząstek popiołów lotnych węgli, kamiennego i brunatnego, jest niezbędne do oceny ich potencjalnego zagrożenia dla środowiska naturalnego.
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The performance of electrothermal vaporization (ETV) and laser ablation (LA) of dry aerosols as sample introduction systems for microwave induced plasma optical emission spectrometry (MIP OES) are compared and evaluated in terms of detection limits, precision and accuracy for the determination of trace elements (Ca, Cd, Cu, Fe, Mg, Mn, Sr, Zn) in the same solid micro samples. In MIP OES both radiation sources can be independently adjusted to optimize the sampling process and then its subsequent excitation. A univariate approach and simplex optimization procedure were used to obtain the best signal/noise (S/N) ratio and derive analytical figures of merit. A comparison using a Student’s t-test between the results obtained by both ETV/LA-MIP OES methods for trace elements, and concentrations in standard reference material (SRM) and certified reference materials (CRMs) showed that there was no significant differences on a 95 % confidence level. The detection limits of the tested elements in solid samples by ETV/LA-MIP OES were in the range of 0.1 to 11 µg g−1 for all elements determined, while the corresponding absolute values in the range of ng. The precision of the results for ETV-MIP OES and LA-MIP OES varied between 2 and 4 % and 3 and 7 %, respectively. The linear dynamic ranges in the ETV/LA-MIP OES are extend over three decades of concentration. The methods were validated by the analysis of NIST SRM 2711Montana Soil, NRCC CRM PACS-2 Marine Sediment and NRCC CRM TORT-2 Lobster Hepatopancreas of different matrix composition and by the standard addition technique.
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