Matrix effect on emission/current correlated analysis in laser-induced breakdown spectroscopy of liquid droplets

摘要

We have investigated influence of matrix salts on the liquid droplets by laser-induced breakdown spectroscopy (LIBS).An electrospray ionization technique coupled with LIBS is employed to generate the microdroplets of the Na sample solution with various matrix salts added.A sequence of single-shot time-resolved LIB emission signals is detected.The LIB signal intensity integrated within a gate linearly correlates with the plasma-induced current response obtained simultaneously on a single-shot basis.The slopes thus obtained increase with the sample concentration,but appear to be irrespective of different matrix salts,added up to a 2000 mg/1 concentration.The matrix salts involved have the same K~+ cation but different anions.Given a laser radiation emitting at 355 nm with the energy fixed at 23+-1 mJ,a limit of detection (LOD) of 1.0 mg/1 may be achieved for the Na analysis.The current normalization might have probably taken into account the ablated amount of the sample and the plasma temperature.Accordingly,the LIB/current correlated analysis becomes efficient to suppress the signal fluctuation,improve the LOD determination,and concurrently correct the matrix effect.