During an undergraduate research experience in the summer of 2019, a handheld X-ray fluorescence (XRF) instrument was used as a screening technique to determine concentrations of lead in paint in Guyanese schools and playgrounds. The XRF determined that the paint samples contained concentrations of lead that surpassed the 90 ppm limit set by United States’ standards and the 600 ppm Guyanese standard. The paint samples consisted of ten paint samples from newly purchased paint containers and field samples which consisted of paint scraped from the walls, desks, and equipment of the schools and playgrounds. All samples were dried, homogenized via mortar and pestle, digested using microwave assisted acid digestion, and analyzed by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results from the ICP-OES and XRF instrument were compared to determine the limitations of the handheld XRF instrument used. For the ten fresh paint samples, the ICP-OES determined lead concentrations to be 20% higher than that of the XRF results determined in the lab. For the samples collected in the field, the ICP determined concentrations of lead equal to and greater than 50% of those concentrations determined in the lab using the XRF. For concentrations of lead in paint under 100 ppm, comparison of XRF to ICP-OES results showed no clear trend. In our hands the XRF underreported concentrations of lead in paint, which may lead to severe health affects for those exposed.  By comparing the concentrations of lead in paint as determined by the ICP-OES and XRF, the validity of the XRF as a quantitative technique can evaluated. This work is significant to both the field of instrumentation and the people directly exposed to these paint samples in Guyana.

Determination of Pb in guyanese paint samples via ICP-OES in comparison to XRF analysis

ACS Spring Meeting 2021

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