Near Infra Red femtosecond Laser Ablation: the influence of energy and pulse width on the LA-ICP-MS analysis of monazite
Résumé
We studied the influence of pulse energy (E 0) and pulse width (s) of Near Infra Red femtosecond Laser Ablation coupled to Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). A particular emphasis was put on the 206 Pb/ 238 U and 208 Pb/ 232 Th repeatability from Moacyr monazite (Itambe, Brazil). Synthetic glass (Standard Reference Material) NIST610 was used as a reference material, as well as a monazite from Manangotry (Madagascar). Pulse energy was investigated in the range E 0 ¼ 0.03 to 0.8 mJ/pulse (s ¼ 60 fs) while pulse width has been studied from s ¼ 60 fs to 300 fs (E 0 ¼ 0.1 mJ/pulse). Data suggest that pulse width has no detectable influence on the accuracy and repeatability of measured elemental ratios in the range of 60-300 fs. Observed measurements repeatabilities are 2.5%RSD and 1.8%RSD for 206 Pb/ 238 U and 208 Pb/ 232 Th, respectively. At 60 fs, the 0.03-0.8 mJ/pulse energy range studied does not induce any detectable change in data accuracy and repeatability. Uncertainties of 1.1-2.8%RSD were obtained for 206 Pb/ 238 U. In the range of E 0 ¼ 0.1-0.8 mJ/pulse, matrix matched calibration using Manangotry monazite gives a similar good repeatability of 2.4%RSD for 206 Pb/ 238 U. No clear matrix effect could be highlighted.