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United States Department of Agriculture

Agricultural Research Service

Research Project: MANAGING AND MODELING DEFICIT IRRIGATION AND LIMITED RAINFALL FOR CROP PRODUCTION IN SEMI-ARID REGIONS

Location: Wind Erosion and Water Conservation Research

Title: System for high throughput water extraction from soil material for stable isotope analysis of water

Authors
item Goebel, Tim
item Lascano, Robert

Submitted to: Trade Journal Publication
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 15, 2012
Publication Date: December 31, 2012
Citation: Goebel, T.S., Lascano, R.J. 2012. System for high throughput water extraction from soil material for stable isotope analysis of water. Journal of Analytical Sciences, Methods and Instrumentation. 2(4):203-207.

Interpretive Summary: The interaction between matter and radiated energy is spectroscopy and commercial instruments to measure these properties are expensive. Furthermore, the procedure to measure stable isotopes of water is time consuming. However, with the introduction of spectrometric instrumentation to measure stable isotopes of water such as the Liquid Water Stable Isotope Analyzer (Model DLT–100 from Los Gatos Inc., Mountain View, CA) the amount of time required to analyze water samples has been greatly reduced and at a reduced cost. Currently, the bottleneck in ecological and hydrological studies is the amount of time that it takes to extract water from soil and plant samples taken in the field. For this purpose we built a cryogenic distillation apparatus, which allow us to separate components. Our unit has six ports and is capable of extracting multiple samples simultaneously, allowing for the analysis of 30 or more samples per day. In this paper we present manufacturing details and the results from experiments where we tested the minimum extraction time necessary to produce an unfractionated water sample from soil samples prepared in the laboratory.

Technical Abstract: A major limitation in the use of stable isotope of water in ecological studies is the time that is required to extract water from soil and plant samples. Using vacuum distillation the extraction time can be less than one hour per sample. Therefore, assembling a distillation system that can process multiple samples simultaneously is advantageous and necessary for ecological or hydrological investigations. Presented here is a vacuum distillation apparatus, having six ports, that can process up to 30 samples per day. The distillation system coupled with the Los Gatos Research DLT–100 Liquid Water Isotope Analyzer is capable of analyzing all of the samples that are generated by vacuum distillation. These two systems allow larger sampling rates making investigations into water movement through an ecological system possible at higher temporal and spatial resolution.

Last Modified: 7/25/2014
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