Sensitivity improvement of laser-induced breakdown spectroscopy to detect heavy metals in water by Tesla coil discharge

Abstract

In this paper, Tesla coil discharge (TCD) was combined with laser-induced breakdown spectroscopy (LIBS). The TCD successfully enhanced the emission of Al atomic lines and AlO molecular bands in Al LIBS, and improved the sensitivity of quantitative analysis of Cr and Pb elements detected by LIBS in water. Firstly, the paper explored the effect of the distance from the TCD tip to the sample surface on the emission of Al atomic lines and AlO molecular bands, finding that 5 mm was the optimal distance. Secondly, the paper investigated the effect of laser energy on the emission of Al atomic lines and AlO molecular bands, finding that 25.1 mJ was the optimal laser energy. Finally, the paper constructed the calibration curves of Cr and Pb elements in water and calculated the limit of detection (LoD), finding that compared with surface enhanced LIBS (SELIBS), TCD–SELIBS reduced the LoDs of Cr and Pb elements from 16.7 ng mL⁻¹ and 12.2 ng mL⁻¹ to 7.3 ng mL⁻¹ and 5.5 ng mL⁻¹, respectively. It indicated that the combination of TCD and SELIBS can achieve high-sensitivity detection of Cr and Pb elements in the water. The combination of TCD and LIBS is a simple, low-cost, easy-to-operate, industrialized and commercialized technology, and has a promising application prospect in the high-sensitivity analysis of heavy metals in water.