ABSTRACT
Lead-based paint is recognized as the principal source of lead in dust and soil. From here it can easily enter a child’s organism, as the result of hand-to-mouth activity typical for young children at play. The preferred method for testing paint for lead is field portable X-ray fluorescence (XRF). A typical portable XRF lead analyzer provides direct readout of lead mass per unit area, and is very easy to operate. The battery-operated analyzer is equipped with a radioactive source to excite lead X-rays, and a gas proportional detector to register the lead radiation intensity. Associated electronics processes a detector signal and converts it into lead mass per unit area. The analyzer described has measurement precision better than 0.05 mg/cm2 of lead at 10 s per sample measuring time. The calibration curve shows very little bias caused by substrate variations. A newly introduced analyzer features a high-resolution semiconductor probe that allows for accurate, substrate-independent lead analysis using K-lines of lead excited with the isotope Cd-109.
