Preparation of graphite targets from small marine samples for AMS radiocarbon measurements

Laval Liong Wee Kwong, Pavel P. Povinec, A.J. Timothy Jull

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

A vacuum sample processing line was set up and methods were developed for the determination of radiocarbon in small-volume seawater and biota samples. Seawater samples (500 mL per borosilicate glass bottle and poisoned with HgCl2) were acidified with 5 mL concentrated hydrochloric acid. Pure N2 was used as a carrier gas to strip CO2 from the samples for 10 min in a circulation mode. After purification through several water traps, the CO2 was isolated cryogenically. Using Na 2CO3 standard solutions, recovery yields were calculated superior to 95 ± 5%. Freeze-dried marine biota samples were thoroughly mixed with Cu(II)O and combusted at 900 °C. The CO2 was purified by passing through Ag wool and Cu granules at 450 °C before reduction to graphite. Finally, graphite was synthesized using Zn dust heated to 450 °C in the presence of an Fe catalyst at 550 °C. Although this method takes about 8 hr (synthesis done overnight), the advantage is that no water vapor by-product is formed to hinder the reaction. The graphite yields, measured both by gravimetric methods and by pressure readings, were 95 ± 5%. Accelerator mass spectrometry (AMS) measurements were carried out at the NSF-Arizona AMS Facility. Results for water samples from the northwest Pacific Ocean are reported which are in agreement with data reported elsewhere.

Original languageEnglish (US)
Pages (from-to)133-139
Number of pages7
JournalRadiocarbon
Volume46
Issue number1
StatePublished - 2004

Fingerprint

Graphite
accelerator mass spectrometry
graphite
Particle accelerators
Mass spectrometry
Seawater
biota
Glass bottles
seawater
Mercuric Chloride
Borosilicate glass
Hydrochloric Acid
Water
Steam
wool
hydrochloric acid
Hydrochloric acid
Wool
Water vapor
Purification

ASJC Scopus subject areas

  • Polymers and Plastics

Cite this

Preparation of graphite targets from small marine samples for AMS radiocarbon measurements. / Kwong, Laval Liong Wee; Povinec, Pavel P.; Jull, A.J. Timothy.

In: Radiocarbon, Vol. 46, No. 1, 2004, p. 133-139.

Research output: Contribution to journalArticle

Kwong, Laval Liong Wee ; Povinec, Pavel P. ; Jull, A.J. Timothy. / Preparation of graphite targets from small marine samples for AMS radiocarbon measurements. In: Radiocarbon. 2004 ; Vol. 46, No. 1. pp. 133-139.
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