AMS and Microprobe Analysis of Combusted Particles in Ice and Snow

Abstract

ABSTRACT. Ice cores and snow pits of the cryosphere contain particles that detail the history of past atmospheric air compositions. Some of these particles result from combustion processes and have undergone long-range transport to arrive in the Arctic. Recent research has focused on the separation of particulate matter from ice and snow, as well as the subsequent analysis of the separated particles for 14C with accelerator mass spectrometry (AMS) and for individual particle compositions with laser microprobe mass analysis (LAMMA). The very low particulate concentrations in Arctic samples make these measurements a challenge. The first task is to separate the particles from the ice core. Two major options exist to accomplish this separation. One option is to melt the ice and then filter the meltwater. A second option is to sublimate the ice core directly, depositing the particles onto a surface. This work demonstrates that greater control is obtained through sublimation. A suite of analytical methods has been used for the measurement of the carbon in snow and ice. Total carbon was analyzed with a carbon/nitrogen/hydrogen (CHN) analyzer. AMS was used for the determination of carbon isotopes. Since source identification of the carbonaceous particles is of primary importance here, the use of LAMMA was incorporated to link individual particle molecular-structural patterns to the same group of particles that were measured by the other techniques. Prior to this study, neither AMS nor LAMMA had been applied to particles contained in snow. This paper discusses the development and limitations of the methodology required to make these measurements.

Radiocarbon Determination of Particulate Organic Carbon in Non-Temperated, Alpine Glacier Ice

“…Two methods have been used by other groups to extract POC from ice samples: filtering of meltwater (Chýlek et al 1987) and sublimating the ice sample in a vacuum while depositing the particles onto a surface substrate (Biegalski et al 1998). Sublimation may provide a better particle recovery yield and would collect a part of the DOC fraction as well, but the meltwater is unavoidably lost.…”

The atmospheric transport and deposition of smelter emissions: evidence from the multi-element geochemistry of snow, Quebec, Canada

“…This polyvinyl membrane has been shown to be cleaner and less adsorbent, thereby reducing element losses (Hall, 1998). Losses to the meltwater phase caused by filtering have been reported to be as high as 35% for some elements (Biegalski et al, 1998). The inside of the sample bags were then rinsed with a known volume of deionized water, which was then passed through the same filter membrane, ensuring that no particulate matter was lost on the interior surface of the bags.…”

A critical evaluation of interlaboratory data on total, elemental, and isotopic carbon in the carbonaceous particle reference material, NIST SRM 1649a

“… 5 First stage thermal oxidation (340 °C) in the closed tube gave the possibility of trapping (rather than evacuating) the first-stage OC gases in the small sample AMS target preparation apparatus for those cases where 14 C AMS was applied to both the OC 340 and the EC carbon from the same sample. It is especially useful when the T340 procedure is adapted for OC, EC 14 C speciation [ 38 ]. …”