METHOD OF MEASURING FORMALDEHYDE CONCENTRATION OF GAS AND MEASURING INSTRUMENT

摘要

A method of speedily measuring the formaldehyde concentration of test gas with high sensitivity without suffering influences of coexisting gases; and a measuring instrument therefor. In particular, a method of measuring the formaldehyde concentration characterized in that a test gas is brought into contact with a filter wetted with a color forming agent consisting of an alkali aqueous solution of 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (AHMT) so as to induce color formation, and that the formaldehyde concentration of test gas is determined on the basis of the degree of color formation; and a measuring instrument including a light emitting element (LED), a light receiving element (PIN type photodiode) and a display arranged so as to optically measure the degree of color formation.