High-sensitive detection of Li and Zn in aqueous solutions using capillary effect-enhanced laser-induced breakdown...

To ensure the safe operation of pressurized water reactors, the real-time and high-sensitive monitoring of Li and Zn in primary cooling water is required. Laser-induced breakdown spectroscopy (LIBS) is a real-time analytical method with great application potential for elemental monitoring in primary cooling water. However, when LIBS directly detects liquids, plasma quenching will reduce the detection sensitivity. In this work, capillary effect-enhanced LIBS (CE-LIBS) was proposed to improve the detection sensitivity of elements in aqueous solutions. Titanium foam substrates were used to enrich the solutes in the solutions. The signal enhancement mechanisms of the method were analyzed. The results showed that the solutes were enriched on the surface of the titanium foam substrate due to the capillary effect. The excitation temperature and electron density of the laser-induced plasma were both increased by the titanium foam substrate, thus increasing the plasma emission intensity. The limits of detection of Li and Zn were 0.41 and 3.83 ng/mL by using CE-LIBS, which can fully meet the requirements of Li and Zn monitoring in primary cooling water. The practicability of the method was demonstrated by analyzing simulated primary cooling water samples, and the recovery values of Li and Zn were in the range of 92-105 % and 96-102 %, respectively. The CE-LIBS does not require additional treatment of the substrate, and the detection process is simple and fast. Results indicated that the CE-LIBS method has broad application prospects in the real-time and high-sensitivity detection of elements in aqueous samples.