Abstract: 3-Methyl-2-benzothiazolinone acetone azine and 2-phenylphenol in 1:4 molar solid mixture reacts specifically with ozone at concentrations of environmental interest to produce a red-violet color. The response is proportional, but not rectilinearly, to ozone concentration at constant exposure time and to time of exposure at constant ozone concentration. The reagent is intended for use with visual comparison standards in passive monitoring devices. No interference was observed from atmospheric oxygen, nitrogen dioxide, sulfur dioxide, or bromine or iodine vapor. Chlorine produced a light yellow color.

Abstract: A sensitive colorimetric detector for formaldehyde vapor is prepared by applying a ketone solution of 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (AHMT) to a support coated with a stable metal bicarbonate to form a compound from which the ketone can be displaced by formaldehyde to yield a chromogen developing a purple color proportional to the amount of formaldehyde. The detector is sensitive to gaseous formaldehyde in air at concentrations below 2 ppm.