Rapid Screening Method for Brominated Flame Retardants and Hexavalent Chromium by Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)

By Directive on RoHS, the use of six hazardous substances is restricted to new electrical and electronic equipment put on the market in Europe from 1 July 2006. The estimation of the type and the content of brominated flame retardants is necessary in plastics of the equipment and the parts. The new technique by using time-of-flight secondary ion mass spectrometry (TOF-SIMS) is proposed for rapid screening test of these substances. We named this technique one droplet extraction method. The sampling method of brominated flame retardants in plastic materials with toluene on silver substrate was investigated for analysis of trace organic compounds by TOF-SIMS. High impact polystyrene (PS) and polypropylene (PP) plates were prepared as evaluation samples containing decabromodiphenylether (DeBDE) of 0.01-10 wt%. Evaluation time that includes sample pretreatment time and measurement time was about 1 hour. The positive quasi-molecular ion (DeBDE+Ag)⁺ (DeBDE cationized with Ag) was suitable for estimation of DeBDE. It was proved that content and spectral intensity had the clear magnitude correlation within 0.01-10 wt% content of DeBDE. It was found that the quick decision of whether the brominated flame retardants in the plastics is the substance restricted or not by Directive on RoHS is possible by this method. We can screen the substances in wide range of content of 0.01-10 wt%. Also it was found that the quick decision of whether hexavalent chromium is present in metals is possible by an application of this method. It was confirmed that one droplet extraction method using TOF-SIMS is a very powerful technique for the rapid screening test of brominated flame retardants and Cr (VI). It can be expected that hazardous substance management that concerns Directive on RoHS becomes more reliable