Capabilities of an Argon Fluoride 193 nm Excimer Laser for Laser Ablation Inductively Coupled Plasma Mass Spectometry Microanalysis of Geological Materials

Abstract

Recent developments in laser ablation inductively coupledfor trace element analysis of geological samples and other environmental materials, owing to the increased sensitivity of plasma mass spectrometry (LA-ICP-MS) have demonstrated its potential for in situ microanalysis for major, minor and ICP-MS and the more eÃcient interaction of UV lasers with solid samples. The use of UV laser beams has led to a more trace elements in solids, such as minerals. With the low backgrounds and high sensitivity of new ICP-MS instruments, controlled ablation process.1 With new generation ICP-MS instruments, modifications of the sample cone geometry and limits of detection of 1-10 ng g−1 in a 40 mm ablation pit for many elements can be reached. Fractionation eÂects due to changes in the torch box configuration, limits of detection for ten selected rare earth elements (REE) of less than 10 ng g−1 diÂerent ablation rates of various elements have prevented quantification without matrix-matched standards with 1064 nm in a 35-40 mm pit can now be reached.2,3 Earlier work by Hirata and Nesbitt,4 Fryer et. al.5 and JeÂries et al.6 demon-Nd5YAG lasers. These eÂects have been reduced but not eliminated using shorter UV wavelengths (e.g. a quadrupled strated the limitations of LA-ICP-MS analysis because of significant fractionation eÂects observed during the ablation Nd5YAG 266 nm). Excimer lasers with wavelengths below 200 nm are expected to reduce fractionation eÂects further, but for some elements, especially Zn, Pb and U, which are of major interest in geological samples. Stix et al.7 reported matrix they present a serious challenge to the design of optical systems, especially if high-resolution UV ablation needs to be eÂects for mineral analysis using synthetic glass standards.Various strategies applied to LA-ICP-MS to minimise these combined with high quality visual observation, which is essential for the study of complex materials, such as geological eÂects have been reported, including moving the stage during ablation,4 spraying water onto the ablation site or the use of samples. An LA system was developed using an homogenized UV laser beam (193 nm, Argon Fluoride excimer) with a several internal standards for specified groups of elements of geochemical interest.8 However, none of these approaches can common UV-visual objective on a modified petrographic microscope with reflected and transmitted light illumination, in be used for routine LA analysis or match the improved ablation characteristics oÂered by the 193 nm excimer system described. combination with a Perkin-Elmer Elan 6000 ICP-MS instrument. The optical system allows imaging of both visible and UV laser light onto the sample surface at the same time. Laser operating parameters and their influence on the ablation process were investigated using NIST SRM 612/610. EXPERIMENTAL Fractionation eÂects due to diÂerential ablation of various ICP-MS Instrumentation elements as a function of time can be reduced to interelement correlation coeÃcients of r=0.9 or better and have becom...

Applications of LA-ICP-MS in the elemental analyses of geological samples

“…The use of shorter-wavelength lasers [30] (i.e. the replacement of 1064 nm wavelength with 266 nm) (frequency-quadrupled output) or 213 nm (frequencyquintupled output) wavelength harmonic generators [31] or the use of 157 nm [32] or 193 nm [33] wavelengths produced by excimer gas lasers) and shorter pulse (e.g. femtosecond lasers) [34] can produce aerosols with smaller particle sizes and thereby reduce the non-stoichiometric effect.…”

Analyte response in laser ablation inductively coupled plasma mass spectrometry

“…The situation is more complex when helium is used as carrier gas and added to the argon in the central channel of the ICP. Laser ablation sampling in a helium atmosphere was found to increase the fraction of small particles in the aerosol, especially when a 193 nm laser is used [5,13,24]. This leads to an increased transport efficiency of the aerosol from the ablation cell to the ICP and also reduces the energy and time required for complete atomization.…”

Quantitative mapping of trace elements in agate using LA-ICP-MS

“…Laser ablation (LA) system is powerful and versatile for in situ microsampling of solid materials including geological samples particularly when it is attached to ICP-MS (e.g., Jackson et al 1992;Norman et al 1996, Günther et al 1997Jeffries et al 1998;Niemax 2001;Heinrich et al 2003;Günther and Hattendorf 2005;Large et al 2009;Koenig et al 2009;Ulrich et al 2009). The development and application of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) have grown with a dramatic rate, and in situ analyses for elemental abundances and isotopic compositions are now performed routinely in numerous laboratories worldwide.…”