Glass particles produced by laser ablation for ICP-MS measurements

Abstract

Pulsed laser ablation (266nm) was used to generate metal particles of Zn and Al alloys using femtosecond (150 fs) and nanosecond (4 ns) laser pulses with identical fluences of 50 J cm -2 . Characterization of particles and correlation with InductivelyCoupled Plasma Mass Spectrometer (ICP-MS) performance was investigated. Particles produced by nanosecond laser ablation were mainly primary particles with irregular shape and hard agglomerates (without internal voids). Particles produced by femtosecond laser ablation consisted of spherical primary particles and soft agglomerates formed from numerous small particles. Examination of the craters by white light interferometric microscopy showed that there is a rim of material surrounding the craters formed after nanosecond laser ablation. The determination of the crater volume by white light interferometric microscopy, considering the rim of material surrounding ablation craters, revealed that the volume ratio (fs/ns) of the craters on the selected samples was approximately 9 (Zn), 7 (NIST627 alloy) and 5 (NIST1711 alloy) times more ablated mass with femtosecond pulsed ablation compared to nanosecond pulsed ablation. In addition, an increase of Al concentration from 0 to 5% in Zn base alloys caused a large increase in the diameter of the particles, up to 65% while using nanosecond laser pulses.When the ablated particles were carried in argon into an ICP-MS, the Zn and Al signals intensities were greater by factors of ~ 50 and ~ 12 for fs vs. ns ablation. Femtosecond 2 pulsed ablation also reduced temporal fluctuations in the 66 Zn transient signal by a factor of ten compared to nanosecond laser pulses.

Elemental Analysis of Glass and Ink by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and Laser Induced Breakdown Spectroscopy (LIBS)

“…It has been reported extensively in the literature [18,[26][27][28][29][30] that nanosecond laser ablation is associated with elemental fractionation, which as alluded to earlier can occur at any stage of the ablation process, including upon laser to sample (laser to matter) interaction, during sample transport into the inductively coupled plasma (ICP), which is partially dependent on particle size distributions, and during particle vaporization inside the ICP itself, which is characterized by plasma conditions and particle size distributions [18,[26][27][28][29][30]. The degree of fractionation in each of these stages not only is dependent on the laser pulse duration (or pulse length) but on other parameters related to the laser utilized (i.e.…”

“…as well as the physical-chemical properties related to the sample matrix itself (i.e. absorption, thermal diffusion, composition, etc) [18,[26][27][28][29][30]. Nonetheless, laser wavelength and pulse duration are believed to be two primary parameters influencing laser ablation and fractionation effects.…”

“…Nonetheless, laser wavelength and pulse duration are believed to be two primary parameters influencing laser ablation and fractionation effects. In the case of glass samples, the ablation efficiency (ablated mass per pulse), particle size, and particle size distributions are dependent on wavelength [18,[26][27][28][29][30].…”

“…shown that improved ablation efficiency, smaller particle size, and narrower particle distributions were obtained when shifting from IR to UV wavelength lasers [28][29][30]. The other factor that must be considered which can improve the ablation characteristics (efficiency, particle size distributions) is laser pulse duration, often called pulse length.…”

“…More specifically, the isotopes analyzed in this study included: 25 Mg, 27 Al, 49 Ti, Hf. The internal standard used in this study is 29 Si because silicon the most abundant element found in float glass and due to its large concentration (>70%) and the associated signal, the concentration difference between glass samples is considered to be negligible.…”