A study on the test conditions and influence factors in online-phosphoric acid method for carbon isotopes of dissolved inorganic carbon compounds in water samples by Gas Bench Ⅱ-IRMS
TANG Wei
WANG Hua
LAN Gaoyong
YANG Hui
WU Xia
TU Linling
YING Qihe
Abstract：The objects of this paper is to determine the test conditions and influencing factors in online-phosphoric acid method by using Gas Bench Ⅱ-IRMS for carbon isotopes of dissolved inorganic carbon compounds in water samples.The equilibrium time,chromatographic column,sample condition,sample volume and the reaction temperature were analyzed comprehensively.The conclusions were as follows,(1) The best equilibrium time of the dissolved inorganic carbon isotope in the water sample was identified.(2)There is obviously positive correlation between inorganic carbon concentration and the sample test signal intensity.(3) In the process of sample testing,the temperature of chromatographic column can not only affect the appearance time of sample peak,but also affect the peak width,peak height and the peak area,leading to different degrees of isotope fractionation.The samples should be kept under 25 ℃ in the reaction process,meanwhile,± 1 ℃ difference in temperature between room temperature and constant temperature sample plate is required.If the temperature difference is too large,there will be water vapor in the sample vial,which will not only lead to the isotope fraction of the sample,but also affect the service life of taking gas needle even lead to serious gas needle blocking.This method can be used to analyze the δ13C values of dissolved inorganic carbon in groundwater,surface water and meteoric water.
Keywords：dissolved inorganic carbon(DIC) in the water samplescarbon isotope(δ13C)test methodsGas Bench Ⅱ-IRMS
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：8( 419-426 )