Which material is used to conduct XRF calibration?

The choice of NIST Standard Reference Material (SRM) for XRF (X-ray fluorescence) calibration is significant because these materials are rigorously tested and certified to have known concentrations of specific elements. The National Institute of Standards and Technology (NIST) provides these materials to ensure accurate and reliable measurements when conducting XRF analyses, which is particularly important in environmental assessments such as lead risk assessments.

Using NIST SRMs helps to establish the accuracy of the XRF instrument by providing a benchmark against which the instrument's readings can be compared. The NIST materials are specifically designed for various applications, and using them allows assessors to account for any system drift and to confirm that the equipment is operating correctly.

In contrast, while ASTM, ISO, and EPA materials may serve important purposes in other contexts, they are not as widely recognized or employed specifically for the calibration of XRF instruments as NIST SRMs are. Therefore, selecting NIST SRMs ensures a higher level of confidence in the calibration and, consequently, the results obtained from the XRF analysis.