FIELD: measurement technology. SUBSTANCE: invention is used to supply specified volume of test substance H2 into test line 2 filled with tested medium, for instance, air, that is provided along section to determine profiles of concentration of liquid or gaseous substances. Column of tested medium is transported through test line 2 in which pressure is rising thanks to cutting on of pressure pump or is falling due to cutting off of suction pump 12. Specified metered volume of tested substance H2 is automatically liberated while pressure p in test line 2 passes preset limiting value. Liberation of specified metered volume of test substance H2 after its trapping by column of tested medium leads to test peak in sensor 11 that is activated by test substance H2 and is connected to test line 2. EFFECT: simple and inexpensive supply of predetermined volume of test substance into test line. 13 cl, 1 dwg
