Analysis of brass and silicate glass by femtosecond laser ablation inductively coupled plasma mass spectrometry using liquid standard calibration

Abstract

Due to the lack of reference materials and increasing requirements on the compositional analysis of aerosols produced by nanosecond laser ablation (ns-LA) using inductively coupled plasma mass spectrometry (ICP-MS), in recent years, the utilization of liquid standards for calibration has attracted particular attention. However, no attempt has yet been made to study the capabilities of liquid standard calibration in combination with femtosecond (fs) LA-ICP-MS even though a benchmark would help answer the question under which circumstances the operation of fs laser systems is recommended to increase precision or accuracy of quantification. In the scope of this study, analyses of brass and silicate glass were carried out by fs-LA-ICP-MS applying on-line addition of desolvated as well as non-desolvated liquid standards. Depending on the material considered, accuracies varied from a few up to 50% for critical elements such as Zn and Cd. The average deviation calculated from concentration values of all elements monitored during the analysis of silicate glass amounted to 11.1% and 8.4% for desolvated and non-desolvated aerosols implying similar but slightly improved performance under “wet” plasma conditions. Furthermore, the Li-, Be-, Na-, Mg-, Al-, Sr-, Cd-, Ba-, and Pb-specific analysis of silicate glass applying “matrix-matched” calibration was found to result in accuracies comparable to those obtained by liquid standard calibration except for Zn and Cd, which improved by 9% and 25% when using a solid calibration material, respectively. In contrast, the precision of analysis decreased due to a higher uncertainty of concentration values specified for the external standard used.