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LABORATORY EVALUATION OF SIX NEW/MODIFIED PORTABLE X-RAY FLUORESCENCE SPECTROMETERS FOR THE MEASUREMENT OF LEAD IN CHARACTERIZED PAINT FILMS AND RESEARCH MATERIAL BOARDS (TECHNICAL REPORT)
Citation:
Williams, E. E., C. A. Clayton, E. D. Hardison, AND W. F. Gutknecht. LABORATORY EVALUATION OF SIX NEW/MODIFIED PORTABLE X-RAY FLUORESCENCE SPECTROMETERS FOR THE MEASUREMENT OF LEAD IN CHARACTERIZED PAINT FILMS AND RESEARCH MATERIAL BOARDS (TECHNICAL REPORT). U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-97/100a (NTIS PB99-162471), 1999.
Description:
A laboratory study was performed in 1994-1995 to identify and estimate the influence of key characteristics for evaluating the performance of portable X-ray fluorescence (XRF) spectrometers. Six new/modified spectrometers, including HNU SEFA-Pb, Metorex X-MET, Niton X-L, Radiation Monitoring Devices (RMD) LPA-1, TN Technologies Pb Analyzer, and Xsirius (now Advanced Detectors), were used to measure levels of lead in NIST SRM 2579 lead-in-paint films and in thicker Research Triangle Institute (RTI)-prepared lead-in-paint films placed on ten different substrates. These substrates ranged from plywood to carbon plate steel. As a result of this study, it was concluded that film thickness influences the precision of K-shell instruments more strongly than the precision of L-shell instruments. Also, L-shell instruments (except for Niton) have significant bias problems with the thicker paint films. Detection limits for K-shell instruments are mainly influenced by instrument precision whereas detection limits for L-shell instruments are mainly influenced by instrument bias. The 95% confidence range of the value of a single future measurement can be estimated at a given Pb concentration on a specific substrate using the data provided in this report. This 95% confidence range is calculated as the sum of the given or expected Pb concentration value and the value of the estimated bias plus/minus the halfwidth of the 95% confidence interval.