Comparative Analysis of 532 nm vs 1064 nm Wavelengths for Nitrogen Detection in Water Using plasma amplification LIBS

Abstract

Plasma amplification laser-induced breakdown spectroscopy (Plasma amplification LIBS) has shown great potential in N elements in water due to high sensitivity, precision, and accuracy. To further reduce interferes of the atmospheric nitrogen, the effect of laser wavelength on the quantitative determination of nitrogen in water was investigated. With short laser wavelength, stronger spectral line intensity, lower interference from atmospheric nitrogen, and superior analytical performance were obtained. The linear coefficient of determination (R²) of the calibration curve improved from 0.2147 to 0.9732, the limit of detection (LOD) was reduced from 18.98 ppm to 3.41 ppm, and the spectral stability, expressed as average relative standard deviation (RSDAV), was reduced from 10.49% to 5.45%. Moreover, the average relative error (REAV) and the root mean square error of cross-validation (RMSECV) for the predicted concentrations were improved by approximately 56.82% and 71.79%, respectively. These results demonstrate that the 532 nm wavelength in plasma amplification LIBS can significantly enhance both the detection sensitivity and the accuracy of quantitative analysis for nitrogen in water.