Portable X-ray fluorescence analyzer for the first level screening of materials for prohibited substances

Abstract

We introduce a small, lightweight (@ 1.5 kg), ergonomically designed, hand-held XRF analyzer configured for in-situ analysis and screening of plastics for regulated elements. We show that the analyzer can achieve minimum detection limits way below a regulatory threshold level of 100 mg/kg for such elements as lead or cadmium. We also show that the portable XRF analyzer can be used for rapid screening of plastics and resins for presence of brominated flame retardants. While it is true that the XRF method cannot distinguish trivalent from hexavalent chromium, it will nevertheless report the total chromium concentration, which is useful and conclusive information if the reported concentration is below the threshold level. Similarly, XRF can only measure bromine concentration as an element regardless whether from the banned or permitted bromine compound. However, the very fact that the instrument can assert the absence of bromine may be sufficient to avoid more labor intensive and costly tests specific for bromine. The subject instrument can also analyze alloys. We show that its performance in analysis of lead in "lead-free" tin solder allows for effective control and prevention of the problem of "tin whiskering".