Direct determination of bromine in plastic materials by means of solid sampling high-resolution continuum source graphite furnace molecular absorption spectrometry

Abstract

This work investigates the potential of high-resolution continuum source graphite furnace molecular absorption spectrometry for the direct determination of bromine in polymers, which could be interesting in view of the current regulations restricting the use of organobrominated compounds. The method developed is based on the addition of Ca (300μg) and Pd (30μg) to favor the formation of CaBr, which is monitored at the main molecular “lines” (rotational spectra) found in the vicinity of 625.315nm.It was found that accurate results could be obtained for all the samples investigated (polyethylene, polypropylene and acrylonitrile butadiene styrene certified reference materials) using any of the lines studied and constructing the calibration curve with aqueous standards. Furthermore, the combined use of the main four CaBr lines available in the spectral area simultaneously monitored permits to easily expand the linear range up to 2000ng, provides a limit of detection of 1.8ng (1.8μgg−1 for a mass of 1mg) and further improves precision to values between 3–7% RSD. Overall, the method proposed seems suited for the fast and simple control of these types of samples (approximately 10min for sample are required), circumventing the traditional problems associated with sample digestion (e.g., losses of volatile compounds), and providing sufficient sensitivity to easily comply with regulations.