کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8039497 1518610 2017 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
14CO2 analysis of soil gas: Evaluation of sample size limits and sampling devices
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سطوح، پوشش‌ها و فیلم‌ها
پیش نمایش صفحه اول مقاله
14CO2 analysis of soil gas: Evaluation of sample size limits and sampling devices
چکیده انگلیسی
Radiocarbon (14C) analysis of CO2 respired from soils or sediments is a valuable tool to identify different carbon sources. The collection and processing of the CO2, however, is challenging and prone to contamination. We thus continuously improve our handling procedures and present a refined method for the collection of even small amounts of CO2 in molecular sieve cartridges (MSCs) for accelerator mass spectrometry 14C analysis. Using a modified vacuum rig and an improved desorption procedure, we were able to increase the CO2 recovery from the MSC (95%) as well as the sample throughput compared to our previous study. By processing series of different sample size, we show that our MSCs can be used for CO2 samples of as small as 50 µg C. The contamination by exogenous carbon determined in these laboratory tests, was less than 2.0 µg C from fossil and less than 3.0 µg C from modern sources. Additionally, we tested two sampling devices for the collection of CO2 samples released from soils or sediments, including a respiration chamber and a depth sampler, which are connected to the MSC. We obtained a very promising, low process blank for the entire CO2 sampling and purification procedure of ∼0.004 F14C (equal to 44,000 yrs BP) and ∼0.003 F14C (equal to 47,000 yrs BP). In contrast to previous studies, we observed no isotopic fractionation towards lighter δ13C values during the passive sampling with the depth samplers.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms - Volume 413, 15 December 2017, Pages 51-56
نویسندگان
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