| 摘要 |
<p>PROBLEM TO BE SOLVED: To correctly measure a ratio of<13> CO2 to the whole carbon dioxide in an expiration gas, by adjusting a pressure reduction state on real time so that a concentration of the whole carbon dioxide in the expiration gas in a cell is kept at a constant value. SOLUTION: A sample-sealing bag 112 is connected to an expiration-collecting apparatus 110, and a pressure in a cell 120 is reduced to a predetermined value. Then, a valve 124 and a check valve 128 are opened to send an expiration gas in the sample-sealing bag 112 into the cell 120. A detecting means monitors a concentration of the whole carbon dioxide in the cell 120 in real time. A control means 141 controls operations of the valve 124, a cylinder pump 118, check valves 126, 128, etc., to adjust a pressure-reduced state in the cell 120 in real time so that the concentration of the whole carbon dioxide monitored by the detecting means is kept at a constant value. the detecting means measures a ratio of<13> CO2 to the whole carbon dioxide in the expiration gas in the cell 120 where the pressure-reduced state is adjusted to maintain the concentration of the whole carbon dioxide in the cell 120 constant.</p> |
