Development of Melting Device for Measurement of Traceable Proxies in Ice Core

Abstract

It has been well known that various proxies in ice core can provide useful information about climate change and atmospheric environment in the past. However, ice core sample can be easily contaminated during drilling, shipping, cutting, and handling and especially, its breaks are the primary source of contamination of the inner core. Therefore, decontamination procedure of ice core sample to remove contaminants of outer layers in ice core is very important. Until now, as a decontamination method of ice core sample, conventional method has been broadly used. This indicates removal of pollutants by mechanical scraping with stainless steel knives or by a series of washing-baths with ultra-pure distilled water. It has advantages such as minimization of interferences between samples, flexible adaptation of extraction time, and stable instrumental analysis. However, as a disadvantage, there have been also reported as low efficiencies of ice core preparation owing to strict and complicated procedures, low resolution (10-20 cm/sample), and difficulties of application to on-line measurement system. As a result, the melting device was developed as an alternative of conventional decontamination method in the early 1990s. Contrary to conventional method, this represented high efficiencies of decontamination, high resolution (≤ 5 cm/sample), and the possibilities of application to on-line measurement system. However, the artifacts from melting head made of metals, the interferences between samples melted in series, recovery efficiencies of traceable element, and instability of instrumental analysis owing to short extraction time and scanning time have to be overcome. Even if various melting devices have been developed, prior to this study, little researches had been undertaken examining systematically them which would be expected to be important in on-line measurement system. In this study, the melting head made of Ti and with 3-channels was constructed to decontaminate discret