Sliding spark spectroscopy – rapid survey analysis of flame retardants and other additives in polymers

A sliding spark spectrometer with a new powerful excitation source was used to detect halogens, flame retardants and metals in non-chlorine containing polymers. The sliding spark source generated discharges using up to 2 kJ of stored energy. The new generator results in improved signal-to-background ratios (SBR) by the factor of three. With this source and a newly developed low cost charge-coupled device spectrometer it was possible to detect elements simultaneously in polymer materials within 5 s. Fillers and white pigments containing Pb, Ti, Zn, Si, Mg, Ca and Ba were qualitatively detected in polyethylene and polypropylene. Acrylnitrile-butadiene-styrene copolymer samples containing different types of flame retardants were analysed and Cl, Br, P, Sb, Al, Mg and Zn were detected. Limits of detection of about 0.1% w/w for elements in chlorine-free polymers were obtained. The use of multiple linear regression gave better results than the use of one individual spectral line.