Evaluation of Portable X-ray Fluorescence Spectrometer for Measurement of Lead in Paint, Soil and Dust.

摘要

Three widely used commercially available portable X-ray fluorescence spectrometers were evaluated for precision and accuracy of measurement of lead in paint. Included were two direct reading instruments and one spectrum analyzer. Test materials were prepared by spiking oil-based and latex paint with white lead and casting the paint into films. The films were then placed on various substrates including wood, plasterboard, metal and concrete and the lead measured using the spectrometers that had been precalibrated by the manufacturers. The overall best results were generally attained with the wood and plasterboard substrates. Using the K shell X-rays, a typical linear range of 0.2 to 10.0 mg sq cm was found. Precisions achieved were 0.1-0.3 mg Pb/sq cm with the laboratory standards. At 1.0 mg Pb/sq cm, bias varied from about -0.4 to +0.3 mg Pb/sq cm. The L shell X-rays were shown to be attenuated by multiple layers of paint as is typically found in older dwellings.