Determination of lead in aqueous solutions using resonant surface-enhanced LIBS

The toxicity of lead (Pb) in water is known to affect cellular components, enzymatic machinery and genomic instability. The detection of lead in water is of great significance. In this study, a method called resonant surface-enhanced LIBS (R-SENLIBS) was proposed to improve the LoD of lead element in aqueous solutions. RLIBS was cooperated with SENLIBS in this method. Lead in aqueous solutions was compounded with a concentration range of 0.01 to 0.6 mg/L. The calibration curve of these solutions was built. The value of coefficients of determination (R2 ) was as high as 0.996 and an LoD of 0.0021 mg/L was achieved for the linear calibration range of 0.01 to 0.2 mg/L. Compared to previously published works involving lead detection by LIBS, the analysis capability of R-SENLIBS proposed in this study is superior to those approaches in reported studies. Moreover, the calibration range and LoD in this work meet the drinking water sanitation standard of China (0.01 mg/L for Pb, GB5749-2006) and WHO guidelines on lead. Trueness evaluation was carried out by spike and recovery experiments in a real sample of tap water, resulting in recovery values in the range of 101–110%. The spectra comparison indicated that impurities in substrate and solution had little influence on the lead signal in R-SENLIBS. The enhancement mechanism of R-SNELIBS was discussed. The on-resonance excitation and stratified structure of the sample were the two main reasons that lead to a tall valid signal of Pb element. In summarily, the method proposed in this study can be an alternative to lead analysis in drinking-water monitoring.