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Title: Laser ablation-inductively coupled plasma mass spectrometry for microscale trace element analysis of solid geological materials

Conference · · Geological Society of America, Abstracts with Programs; (United States)
OSTI ID:5767499
 [1]
  1. Union College, Schenectady, NY (United States). Geology Dept.

In traditional inductively coupled plasma mass spectrometry (ICPMS) solid samples are dissolved and introduced into the plasma (ion source) as a spray in an argon carrier gas. About 70 elements can be easily analyzed with good analytical precision. Without preconcentration, detection limits in the solid vary from about 100 ppm for some light elements to about 1 ppb for some heavy elements. To avoid sample dissolution a pulsed laser can be used to evaporate small volumes of solids, from which the vapor and condensate is carried into the plasma for conversion to ions and analysis. Most laser ablation ICPMS (LAICPMS) systems are based on a pulsed Nd-YAG laser. The laser is focused on the specimen through a microscope, with beam spot sizes ranging from about 200 to 20 [mu]m depending on the beam optics. Nd-YAG lasers produce 1,064 nm infrared light in the fundamental mode, which is absorbed well by dark minerals or minerals containing substantial manganese, iron or certain other transition elements. Unfortunately, 1,064 nm light couples poorly with pale-colored, transition element-poor minerals including many carbonates, feldspars, and feldspathoids. Commercially available harmonic generators can be added to the laser beam line to produce higher order harmonics of the 1,064 nm fundamental mode at 532 nm (green), 355 nm (blue), and 266 nm (UV). The UV wavelength couples well to most minerals and should be capable of producing reproducible ablation pits in most minerals, as well as the possibility of pits [<=] 10 [mu]m. Practical experimentation on LAICPMS at UV wavelengths has only taken place in the past 18 months or so, and laser-mineral coupling has been shown to be good. LAICPMS promises to rival the ion probe in the determination of absolute concentrations of many elements, with much reduced matrix effects, faster analytical throughput, and lower cost.

OSTI ID:
5767499
Report Number(s):
CONF-9303211-; CODEN: GAAPBC
Journal Information:
Geological Society of America, Abstracts with Programs; (United States), Vol. 25:2; Conference: 28. annual Geological Society of America (GSA) Northeastern Section meeting, Burlington, VT (United States), 22-24 Mar 1993; ISSN 0016-7592
Country of Publication:
United States
Language:
English