Micro-hole Jet-assisted LIBS Online Analysis Method And Its Application Research In The Detection Of Marine Metal Elements

Laser induced breakdown spectroscopy(LIBS)is a analysis technique that a high energy laser is focused on a sample,and the plasma will be induced.Then the chemical composition can be analysised.LIBS has been widely applied to many fields for its characteristics of simple,fast,non-contact on-line and so on.The determination of marine metals by LIBS in situ is expected to be applied in marine scientific investigation and water resources environmental monitoring.However,in the field of ocean exploration and water environment monitoring,because of the complex matrix effect,the LIBS technology has been greatly restricted to the determination of the metal elements in aqueous solutions.In order to determin the metal elements in aqueus solutions on line,a micro hole sprayer assisted LIBS system is designed and realized.The system consists of micropore hole and piezoelectric ceramic slice,which can convert liquid samples into small droplets and spew rapidly and continuously.Then the droplets will form of columnar dense droplets.Taking Ca element as an example,the influence of laser energy,micro hole size and other experimental parameters is analyzed,and the experimental parameters are optimized.The electron density and electron temperature of the plasma are calculated,and the physical characteristics of the plasma are analyzed.The ability to continuous quantitative detection is verified.The LOD of the Ca element can reach 0.96 mg/L,and there is a good linear relationship between the peak intensity and the concentration in the range of 0 ~ 1124mg/L,and the ability to on-line continuous quantitative detectionis evaluated.In view of the actual demand of marine applications,the system has been improved and the metal elements in the ocean and specific areas are detected,and the detection limit is calculated.Except for Fe?K and Cd,the detection limits of all other elements are below 1ppm.According to the needs of marine applications,the metal elements in ocean,such as Na,Mg,K,Cd,Mn and Li,were detected.In order to solve the nonlinear problem when the concentration of samples are high,three different fitting methods are proposed,and the method is verified by the Na element.Then the salinity of seawater is calculated by the concentration formula.Finally,the content of the full text is summarized.According to the actual application,the future direction of work is proposed.