Determination of trace heavy metal ion Tl(I) in water by energy dispersive X-ray fluorescence spectrometry using prussian blue dispersed on solid sepiolite.

X-ray fluorescence (XRF) offers the advantage of performing measurements without damaging or consuming the sample, enabling rapid and simultaneous multi-element analysis. It has been widely applied in environmental monitoring, materials science, geology, and medicine, but not in water. Here, a novel method is proposed that combines energy-dispersive X-ray fluorescence spectroscopy (EDXRF) with prussian blue dispersed on solid sepiolite nanomaterials (PB/SEP) and an integrated enrichment-separation device to detect trace heavy metal ion Tl(I) in water environments. The water sample passes through the detachable enrichment component, and subsequently, PB/SEP is used as a solid adsorbent for the pre-enrichment of Tl(I) in the water sample. This process eliminates the cumbersome separation steps and saves analysis time. The research elucidates the impact of sample pH, flow rate, volume, and interfering ions on elemental recoveries, demonstrating that the proposed method offers a low detection limit of 0.057 μg/L, but also maintains high precision, with the RSD of less than 4.39 %. Furthermore, the PB/SEP magnetic nanocomposite was successfully applied to the tap water sample and river water sample with recoveries ranging from 93.5 % to 128.3 %, confirming the accuracy and practicality of the analytical method.