GB1511286A - Process for the determination of chemical compounds by chemiluminescence with ozone - Google Patents

Abstract

1511286 Chemiluminescence gas analysis PETROLEO BRASILEIRO SA PETROBRAS 11 Sept 1975 [20 Sept 1974 22 Aug 1975] 37447/75 Headings G1A and G1B A chemiluminescence gas analysis method comprises measuring and recording luminescence of the gas during reaction with ozone in a series of stages comprising either (a) measuring luminescence at selected different temperatures at which each class of suspected compound reacts in turn with ozone or (b) at a temperature at which all classes react, measuring luminescence successively at respective wavelengths at which each class reacts. A reaction chamber 24, having a sealed quartz window 32, is provided with mutually-perpendicular bores 45, 35, opening into a recess 48 for introducing respectively ozone and a specimen gas, e.g. gas chromatograph effluent containing inert carrier gas and an unknown hydrocarbon mixture. An exhaust passage 34 is connected to suction apparatus (15, 14, 13) Fig. 2 (not shown) via a purging flask or trap (12) to render the ozone harmless. A cooling chamber 50 sealed with a second quartz window 41 and attached to a photomultiplier 37, is surrounded by a cooler 39 having a refrigerant circulation passage 51. The reaction chamber 24 is heated by elements inserted in openings 30, a further opening 31 being provided for a thermocouple and electrical connections. The specimen gases may be pre-heated by a coiled portion of gas admission tube 46 located in an annular space between hollow cylinders 26, 27, the inner cylinder containing a controllable heating element in a bore 28 and a thermocouple in a bore 29. In use, hydrocarbons of various kinds and affinities may be distinguished by the selective onset of chemiluminescence within different temperature ranges between e.g. 20 and 250‹C, and by characteristic spectra selected by filters or monochromaters (not shown). The photo-multiplier output is connected to a pulse discriminator (21), (Fig.2), a signal convertor (22) and a recorder (23).