A comparison of different analytical techniques (energy dispersive X-ray fluorescent spectrometry, bomb calorimetry combined with ion chromatography and inductively coupled plasma-optical emission spectrometry) for the determination of the bromine and antimony content of samples

In recent years, there has been intensive research into the use of pyrolysis to process toxic plastics from waste electrical and electronic equipment (WEEE). During pyrolysis, the fate of the bromine and antimony content of the plastics is critical therefore, new and improved analytical techniques for analysing these elements in the pyrolysis products are being sought. In this work, the effectiveness of energy dispersive x-ray fluorescent spectrometry (EDXRFS) for the determination of bromine and antimony content of pyrolysis oils from waste electrical and electronic equipment have been tested. Samples were obtained by the pyrolysis of brominated high-impact polystyrene (Br-HIPS) and brominated acrylonitrile-butadiene-styrene (Br-ABS) at temperatures from 360 to 440 °C. The concentration range of both the bromine and antimony in the samples was very broad (0.05-17.94 wt% and 0.03-8.54 wt% respectively). The results from EDXRFS to those of more traditional and time consuming methods; bomb calorimetry combined with ion chromatography (EPA method 5050) for bromine and acid digestion combined with inductively coupled plasma-optical absorption spectrometry for antimony were compared.Based on our measurements, different statistical parameters were calculated for each analytical technique, which demonstrated that EDXRFS had been successfully applied to the determination of bromine and antimony concentration in the pyrolysis oils of Br-HIPS and Br-ABS. Errors resulting from matrix effects did occur, in particular correlations were found between the nitrogen content of the samples and the difference in bromine and antimony measured by EDXRFS and other methods (ion-chromatography and ICP-OES). However, these differences were found to be statistically insignificant, so we could conclude that EDXRFS is a suitable technique for analysing the bromine and antimony content of pyrolysis oils.