The method of spatially selective laser-stimulated absorption (SS-LSA) was proposed to reduce self-absorption in laser-induced breakdown spectroscopy (LIBS). Through scanning intensity maps of analytes, it was discovered that elemental distribution was inhomogeneous in the formed plasma. Taking copper (Cu) and chromium (Cr) elements in steel as examples, the distribution of Cu and Cr has its own characteristics. By focusing the laser beam on the optimal locations of the plasma with an optical parametric oscillator (OPO) wavelength-tunable laser, the linear determination coefficient (R² factor) for Cu and Cr elements can reach 0.993 and 0.999, respectively. For Cu determination, compared with LIBS and LSA-LIBS, the root-mean-square error of cross-validation (RMSECV) of SS-LSA-LIBS decreased by 81 and 52%, respectively. The analytical accuracy of the quantitative analysis was much higher than those of conventional LIBS and LSA-LIBS, which indicates that the proposed method can effectively reduce self-absorption and improve LIBS analytical performance.

A simple and ultrasensitive method for detecting Pb ²⁺ using resin-enrichment combined with laser-induced breakdown spectroscopy assisted by laser-induced fluorescence.

Excessive emissions of heavy metals not only cause environmental pollution but also pose a direct threat to human health. Therefore, rapid and accurate detection of heavy metals in the environment is of great significance. Herein, we propose a method based on laser-induced breakdown spectroscopy (LIBS) combined with filter paper modified with bovine serum albumin-protected gold nanoclusters (LIBS-FP-AuNCs) for the rapid and sensitive detection of Cr³⁺ and Mn²⁺. The filter paper modified with AuNCs was used to selectively enrich Cr³⁺ and Mn²⁺. Combined with the multi-element detection capability of LIBS, this method achieved the simultaneous rapid detection of Cr³⁺ and Mn²⁺. Both elements showed linear ranges for concentrations of 10–1000 μg L⁻¹, with limits of detection of 7.5 and 9.0 μg L⁻¹ for Cr³⁺ and Mn²⁺, respectively. This method was successfully applied to the determination of Cr³⁺ and Mn²⁺ in real water samples, with satisfactory recoveries ranging from 94.6% to 105.1%. This method has potential application in the analysis of heavy metal pollution.

Heavy metals in soil pose risks to human health and can cause poisoning or even death. It is therefore important to develop a method for quickly determining the heavy metal contents of soil. Laser-induced breakdown spectroscopy (LIBS) is a new technique for determining elements that has been used widely to analyze soil. LIBS allows rapid on-site soil analysis. However, matrix effects caused by different soil particle sizes prevent accurate measurements of elements in soil if the soil is not preprocessed. We developed a solid phase conversion (SC) and LIBS method to improve the stability of measurements of heavy metals in soil and compared the results with the results of direct measurement and tableting methods. The relative standard deviations for the Pb and Cr contents determined by SC-LIBS were 11% and 10%, respectively. The mean relative standard deviations for Pb and Cr were 71.4% and 53.4% lower, respectively, for SC-LIBS than for the direct measurement and tableting methods. The root mean square errors for SC-LIBS were 25.37 and 36.89 mg kg⁻¹ for Pb and Cr, respectively. The average root mean square errors for Pb and Cr were 27.1% and 19.7% lower, respectively, for SC-LIBS than for the direct measurement and tableting methods. The limits of detection for Pb and Cr determined by SC-LIBS were 9.34 and 3.60 mg kg⁻¹, respectively. The results indicated that SC-LIBS effectively decreases matrix effects and improves the accuracy and stability when determining heavy metals in soil.