Lawrence Berkeley National Laboratory

Gas flow of He–Ar mixtures affects the signals of a tandem LIBS and LA-ICPMS system. The integration of LIBS and LA-ICPMS allows for simultaneous determination of a wide range of elements and isotopes. Achieving high-precision quantitative analysis in this dual-technique approach requires establishing the optimal gas environment in the sample chamber. This study evaluated the impact of gas flow on a tandem femtosecond LIBS and LA-ICPMS system. By premixing helium and argon at various ratios, we created gas mixtures with gradient properties. NIST SRM 610 was used as the standard sample to assess the signal intensity and stability of optical emission spectroscopy and mass spectrometry. Our results showed that the LIBS intensity of Li( I ) 610.35 nm, Li( I ) 670.77 nm and Ca( I ) 644.90 nm, along with their relative standard deviation, increased with the proportion of argon in the gas mixture. Conversely, the LA-ICPMS intensity and relative standard deviation of each element decreased with the argon proportion in the carrier gas. LIBS appears to favour an argon ambient gas, while LA-ICPMS prefers helium as the carrier gas. To balance both modules, we tested various helium and argon gas mixtures. A mixed gas composed of 700 ml min −1 helium and 400 ml min −1 argon was found to be the optimal gas flow for the tandem system, considering signal intensity and relative standard deviation. This study highlights the significant influence of gas flow in optimizing the signal of optical emission spectroscopy and mass spectrometry in a tandem system, enhancing the precision and accuracy of elemental analysis for both modules.