Research on water heavy metal element detection using surface-enhanced LIBS based on coffee ring enrichment

Abstract

In order to enhance the stability and lower the detection limit of Laser-Induced Breakdown Spectroscopy (LIBS) technology, gelatin was introduced into the test solution in this study to enrich heavy metals using the coffee ring effect. The effects of different gelatin mass fractions on the surface deposition morphology of droplets and the intensity of spectroscopy were analyzed. Explored the spectral enhancement mechanisms of four substrate materials. The results demonstrated that the best coffee ring enrichment was achieved with a gelatin mass fraction of 2.5 %. The signal-to-noise ratios of Cu and Cr were enhanced by 5.5 and 3.6, and the relative standard deviations decreased by 59.5 % and 53.8 %. When Zn plate was used as the substrate material, the detection limits for Cu and Cr were 0.715 mg/L and 3.881 mg/L. The research indicates that surface-enhanced LIBS based on coffee ring enrichment can improve spectral stability and lower the detection limit.