SIMULTANEOUS MEASURING METHOD FOR STABLE ISOTOPE ABUNDANCE OF CARBON AND NITROGEN BY MASS SPECTROMETER

摘要

PURPOSE:To measure in a short time without requiring skill, by introducing a sample into a piston cylinder after converted into gaseous state under the existence of carrier gas and supplying to a mass spectrometer continuously as a constant quantity of a sample pulse in accordance with the recprocating motion of a piston. CONSTITUTION:Gaseous oxygen and gaseous helium are introduced into a combustion tube 2 and a sample S is burnt here and then, combustion gas composed of CO2, NO2 and H2O is obtained by the perfect combustion of organic matter, NO2 is reduced to N2 when the combustion gas is passed through a reduction tube 4 and said gas is introduced into a moisture absorption tube 27 from a line 26 converting into a constant volume sample pulse by a reciprocating motion of a piston 6. Here, gaseous carbon dioxide is removed from the gas in a absorbing tube 28 of carbon dioxide after the moisture in the gas is separated by adsorption. Then, a mixture of CO2 and N2 is supplied to a mass spectormeter MS from a line 31 and N2 in the gas is supplied to the spectrometer MS from a lime 34 and then, the measurement is performed.