Online Detection Method of Metal Element Content in Precipitation

To realize the online detection of metal element content in precipitation, the laser induced breakdown spectroscopy (LIBS) was used to build an online detection platform. The calcium (Ca) and magnesium (Mg) elements in precipitation samples were analyzed. 10 kinds of mixed solutions of Ca and Mg elements with different concentrations were prepared to simulate precipitation samples by adding Ca(NO3)2 and MgSO4 solutes into distilled water. 7 kinds of mixed solutions were used as standard water samples. The optimal acquisition delay time of laser pulse and spectrometer was analyzed. The spectral line analysis of LIBS data was conducted by internal calibration method. The calibration curves of Ca and Mg were obtained. The obtained linear correlation coefficients of the fitting curve for Ca and Mg were 0.971 and 0.984, respectively. The detection limits were 9.83 ppm and 6.25 ppm, respectively. The other 3 kinds of mixed solutions were used as the standard water samples. The experiment showed that the content of Ca and Mg elements detected online has little different with the content of the actual configuration. The phenomenon provides a feasible method to detect the chemical composition of metal elements in precipitation, which has a promising application in the field of meteorological observation.