Highly sensitive analysis of trace elements in aqueous solutions using surface-enhanced and discharge-assisted laser-induced breakdown spectroscopy

Abstract

By combining surface-enhanced and discharge-assisted laser-induced breakdown spectroscopy (LIBS), the study successfully realized the quantitative analysis of trace heavy metals Cr, Cu, and Pb in aqueous solutions. We used an Al metal plate to convert a liquid sample into a solid sample to overcome low sensitivity and accuracy in the direct detection of water samples by LIBS technology. Firstly, the influence of discharge-assisted LIBS on the spectral intensities of trace Cr, Cu, and Pb in the aqueous solutions was discussed. The result showed that compared to the case of surface-enhanced LIBS technology without the discharge, discharge-assisted and surface-enhanced LIBS enhanced the Cr(I), Cu(I), and Pb(I) line intensities. Secondly, the calibration curves of Cr, Cu, and Pb elements were constructed to calculate the limit of detection (LoD). Compared to the case of surface-enhanced LIBS technology without the discharge, the LoDs with discharge-assisted and surface-enhanced LIBS reduced from 3.33 ng mL⁻¹, 5.55 ng mL⁻¹, and 10.07 ng mL⁻¹ to 1.19 ng mL⁻¹, 2.64 ng mL⁻¹, and 3.86 ng mL⁻¹, respectively. The combination of surface-enhanced and discharge-assisted LIBS technology can carry out highly sensitive analysis of trace heavy metal Cr, Cu, and Pb in aqueous solutions.