Non-matrix matched calibration using near-IR femtosecond laser ablation inductively coupled plasma optical emission spectrometry

Abstract

The facilities of near-IR (NIR) femtosecond laser ablation (fs LA) inductively-coupled plasma optical emission spectrometry (ICP-OES) for the analysis of solid materials applying non-matrix matched standards have been examined. Three sets of metallic and dielectric standards (brass, aluminium, silicate glass) have been analyzed for Zn and Cu using He as buffer gas. It has been found that the measured Zn/Cu ratio of these standards remains nearly unchanged in the fluence range considered (0.8 J cm⁻² ≤ F ≤ 11.0 J cm⁻²). At fluences close to the threshold, however, the Zn/Cu ratio for brass and aluminium tends to slightly increase, suggesting preferential evaporation of Zn during the ablation process. Furthermore, LA above a fluence of 5 J cm⁻² resulted in linear, matrix-independent calibration graphs. According to the results achieved, NIR fs LA-ICP-OES carried out in the medium and high fluence regime permits efficient suppression of fractionation and performance of accurate analyses even if non-matrix matched standard materials have to be used.