Patent ID: 7462836

Claim:
A method for separating and measuring 37 Ar from a soil gas sample or an atmospheric sample, which comprises the following steps in turn: 1) sampling, which comprises collecting soil gas sample or directly collecting atmospheric air with a syringe sampler; 2) eliminating impurities, which comprises passing the gas sample as collected through a room temperature molecular sieve column to eliminate H 2 O and CO 2 , and through a room temperature deaerator to eliminate O 2 ; 3) separating, which comprises allowing the gas sample after eliminating impurities to be adsorbed by entering a sampling column positioned in a cold trap at a temperature from −170° C. to −185° C., and then washing the sampling column with a He gas stream, whereby a majority of Ar and partial O 2 and N 2 at the front end of the sampling column are carried by the He gas stream to enter a molecular sieve collection column in a liquid nitrogen cold trap; 4) purifying, which comprises taking the collection column out of the cold trap, and washing it with a He carrier gas stream after heating, whereby Ar, O 2 and N 2 are detached from the collection column before entering a separation column in a chromatographic system at a temperature from −20° C. to −70° C. for chromatographic separation; allowing the gas after separation to enter a room temperature catalytic deoxidizing column, whereby eliminating trace O 2 that is inseparable from Ar and further purifying Ar; then, allowing the gas after purification to be analyzed by entering a thermal conductivity detector; 5) measuring the sum of Ar, which comprises measuring the sum of Ar as collected with the thermal conductivity detector; 6) collecting Ar, which comprises collecting Ar in tail gas out of the thermal conductivity detector with an activated carbon collection column positioned in a liquid nitrogen cold trap heating the activated carbon collection column, and collecting Ar gas as desorbed with a proportional counter; and 7) measuring the activity of 37 Ar, which comprises filling the proportional counter with a working gas methane in a ratio of Ar/CH 4 =9:1, and measuring the activity of radioactive 37 Ar after thoroughly mixing the two gases.