Analysis of Tclp Extracts by X-ray Fluorescence

The toxicity characteristic leaching procedure (TCLP) is one test used by the U.S. Environmental Protection Agency (EPA) to determine if a waste material is hazardous; the TCLP test is widely used by the environmental testing community. The elements of concern for toxicity are arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver. As an environmental forensic laboratory, the National Enforcement Investigations Center (NEIC) of EPA often conducts TCLP testing. It is our practice to confirm TCLP test results that may indicate a violation of a regulation with an alternate technique. This project explored the use of X-ray fluorescence (XRF) as a confirmation technique for the determination of inorganic elements in TCLP extracts. The sample preparation approach investigated was the microliter droplet on filter paper technique. The sample carriers were analyzed under vacuum with a conventional wavelength dispersive XRF spectrometer. Results indicated that TCLP extract analysis by XRF using filters compares well to analysis by inductively coupled plasma-optical emission spectroscopy (ICP-OES). In real-world samples, correlations of 0.98 and 0.94 were achieved for lead and cadmium analyses by XRF and ICPOES, supporting our intent to use XRF as a confirmation technique.