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In this work, a new portable device based on a monomode microwave applicator was developed and applied for microwave-assisted solid sampling analysis coupled to flame furnace atomic absorption spectrometry (MW-SS-FF-AAS). As an example of application, Hg was determined in polymer samples in order to demonstrate the feasibility of the proposed system. Polymeric samples were weighed directly on a quartz boat, containing a microcrystalline cellulose pellet wetted with 6 mol L−1 NH 4 NO 3 solution, which was introduced into the microwave system for the combustion step. Oxygen flowed continuously through the quartz tube for sample combustion, as well as to carry the combustion products to the flame furnace (FF) atomizer. Microwave irradiation was kept on up to sample ignition (generally <5 s). After that, microwave was turned off and atomic absorption signals were integrated. The instrument calibration was possible using aqueous reference solutions after optimization of some operational conditions such as mass of combustion aid, volume of igniter, oxygen flow rate, FF tube design, flame stoichiometry, and sample mass. Under optimized conditions, the LOD and LOQ were 0.2 and 0.7 μg g−1, respectively, which were suitable for Hg determination at low concentration in polymers. In addition, no statistical difference was observed between the results obtained by MW-SS-FF-AAS and the certified values of certified reference materials (ERM EC 681k and ERM EC 680k). The proposed microwave-assisted solid sampling system is portable and might be easily adapted to any conventional atomic absorption spectrometer, increasing the range of applications of this well-known technique. Unlabelled Image • A portable microwave-assisted solid sampling system is proposed. • It can be easily adapted to any conventional atomic absorption spectrometer. • The method avoids sample digestion, which requires the use of large volumes of reagents. • Calibration was performed using reference solutions, avoiding the necessity of CRMs for calibration. • The LOQ (0.7 μg g−1) was suitable for Hg determination in polymers at low concentration. [ABSTRACT FROM AUTHOR]

In this work, a method for poly(vinyl chloride) (PVC) analysis by inductively coupled plasma optical emission spectrometry (ICP-OES) was developed. Samples were digested by microwave-induced combustion (MIC) and thirteen elements (Ba, Cd, Co, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sr, V and Zn) were determined by ICP-OES. Operational conditions of MIC were investigated allowing quantitative determination of all the analytes and suitable results were achieved using a 3 mol L −1 HNO 3 solution. Microwave-assisted wet digestion (MAWD) using closed quartz vessels and a single reaction chamber microwave digestion system (MAWD–SRC), were also evaluated for PVC digestion for results comparison. All the evaluated sample preparation methods were considered suitable for PVC digestion but MIC was preferable due to the possibility of using diluted HNO 3 instead of concentrated reagents and due to the better digestion efficiency. The residual carbon content (RCC) in digests obtained by MIC was significantly lower in comparison with the values obtained after MAWD and by MAWD–SRC. Accuracy for the proposed method was better than 94% for all analytes by comparison of results with those obtained by neutron activation analysis (NAA). Using MIC, it was possible to digest a relatively high sample mass (500 mg) and up to 8 samples in less time (25 min) in comparison with MAWD and MAWD–SRC (about 60 min for both methods). The efficiency of digestion by MIC was higher 99% and lower limits of detection (as low as 0.1 µg g −1 ) were obtained avoiding the use of concentrated acids that is of great concern according to the current green chemistry recommendations. [ABSTRACT FROM AUTHOR]