Field Sampling with a FP‐XRF: A Real‐World Lab Experience

Abstract

A field sampling laboratory experiment was developed so students would gain experience sampling on a field site and have an introduction to XRF spectrometry. The experiment used a rented field portable XRF instrument (FP‐XRF) to quantify the lead in soil samples collected adjacent to an urban highway and explored aspects of the USEPA Method 6200. Rainy weather conditions eliminated the possibility to record spectra in the field, so sample preparation procedures were modified to model the typical in situ and intrusive mode of spectral investigations stated in the method. The lead content in the soil samples collected at 15 ft from the highway were determined to be greater than 2000 ppm. The soil lead content decreases as the distance perpendicular to the highway increases. The site background sample collected from 300 ft away is nearly equal to the instrumental lead detection limit of 20 ppm. The experiment demonstrated the need to collect replicate spectral data for in situ sampling and that sample homogenization is a critical step in the intrusive sample analysis mode.