In a method of formaldehyde determination by measuring the fluorescence of a fluorescent substance formed by the reaction of a formaldehyde-containing solution with a fluorescent reagent capable of forming said fluorescent substance by the reaction with formaldehyde, the improvement which comprises using as said fluorescence reagent a compound represented by the general formula CH.sub.3 C(NH.sub.2).dbd.CHCO.sub.2 R, wherein R represents an alkyl group having 1 to 4 carbon atoms.
A novel colorimetric reagent for the selective determination of formaldehyde in solution or in air is described. The reagent comprises at least two chemicals: rubeanic acid or a rubeanic acid derivative, and a cyano complex of a metal. Upon addition of formaldehyde, a color is formed which is quantitatively related to the number of formaldehyde molecules reacted. The chromophoric reagent can be mixed with other inactive ingredients such as stabilizers, buffers, polymers, etc. and used in solutions as a coating on a flat surface, or on beads to detect and determine formaldehyde colorimetrically. One particular application of the colorimetric reagent is in a direct reading colorimetric gas dosimeter for formaldehyde.
