[Investigation of Cu Concentration in the CuSO4 Solution by Laser Induced Breakdown Spectroscopy]

In this paper, the concentration of copper element in the CuSO4 solution was measured by Laser Induced Breakdown Spectroscopy with aqueous jets. We used the CuSO4 solution with 7 kinds of concentration and adopted statistical exploratory data analysis method to get calibration curve of Cu, whose linear fitting coefficient R2 was larger than 0.98. The average RSD of LIBS was 6.96%, and the average LOD of Cu was determined to be 12 ppm. The values of relative error by analyzing Cu I 324.75 nm and Cu I 327.40 nm spectral lines were respectively 6.52% and 5.86%, with the method called leave-one-out cross validation. The experimental relative error had a greater value, which was 10.3%, when the concentration of Cu was 10 ppm. However, the relative error decreased to 1.1% for the concentration of 2000 ppm, which indicated that LIBS need to be studied on its accuracy further in detecting lower analytical concentrations. LIBS has the promising application in detecting heavy metal elements in the environmental wastewater pollution.