Publication Date:
2019-07-17
Description:
Application of LA-ICP-MS in polar ice core studiesReinhardt, H., Kriews, M., Miller, H., AWI Bremerhaven/DLüdke C., Hoffmann E., Skole J., ISAS Berlin/DDr. Heiko Reinhardt, Alfred-Wegener-Institute for Polar and Marine Research,Am Handelshafen 12, 27570 BremerhavenEmail: hreinhardt@awi-bremerhaven.deThe direct determination of element signatures in polar ice core samples from Greenland by laser ablation with subsequent inductively coupled plasma mass spectrometry analysis has been investigated. The ice shields of the polar regions are important climate archives and they provide useful insight to the history of the Earth climate back to about 500,000 years. The analysis of element signatures in ice cores yields information about the strength of sources and transport mechanisms for aerosols in the paleoatmosphere as well as about the paleovolcanism. By means of a laserbeam at a wavelength of 1064 nm material from the ice surface is ablated. The ablated sample aerosol is introduced to an ICP-MS (ELAN 6000). The great advantages of the new technique in comparison to solution analysis are the high spatial resolution, the fast analysis of total element content (soluble and insoluble components) and a reduced risk of contamination. A cryogenic sample chamber (CRYOLACTM) enables the element determination in ice directly from the solid (frozen) state. A procedure was developed to analyse up to 39 elements (traces: Mg, Al, Fe, Zn, Cd, Pb and some rare earth elements; minor constituents: Ca and Na) in ice samples from Greenland with a previously not achieved spatial resolution of 4 mm along the core axis. This resolution is helpful to detect seasonal variations of element concentration in thin annual layers of deep-ice. We report operating conditions and analytical performance of the experimental set up, the improvement of signal stability by 17OH internal standardisation and applying of a desolvation unit. Calibration of the system was performed with frozen multielement standard solutions along a special preparation procedure. Detection limits for the tracers Na, Mg (sea salt), Al (mineral dust) and Zn (anthropogenic source) are between 0.1-1 µgkg-1. Best detection limits in the range of 0.001-0.01 µgkg-1 were reached for Co, Pb and all rare earth elements. Due to interferences, the element Ca could not be analysed at trace levels. To validate the method, frozen standard reference materials were measured. The recovery is about ± 10 %. Greenland ice core samples from different ages were analysed with the new technique. The results were compared with values from solution analysis, available published data and the particle content. The high spatial resolved analysis show strong inhomogeneous element concentrations along the core axis due to seasonal variations of element deposition. The data from solution analysis (solution ICP-MS and ion chromatography) are in a good agreement for many determined elements.Literature:[1] Reinhardt, H., Kriews, M., Miller, H., Schrems, O., Lüdke, C., Hoffmann, E., Skole, E., Fres. J. Anal. Chem. 2001, 370, 629.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Conference
,
notRev
Format:
application/pdf
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