Formaldehyde test element and method of use
AssigneeEastman Kodak Company
InventorDavid J. Young
Life of this patent
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Abstract
A test element is provided which can detect and measure extremely low concentrations of formaldehyde in the environment. The test strip comprises a support having thereon a formaldehyde-sensitive layer comprising an inert formaldehyde-permeable binder which stabilizes sulphite ions against aerial oxidation having dispersed therein pararosaniline or an acid derivative thereof and sulphite ions. The test element requires no processing and can be fixed to obtain a permanent record.
Claims9
An element for determining the amount of formaldehyde present in a gaseous environment comprising a support having thereon a formaldehyde-sensitive layer comprising gelatin, pararosaniline or an acid derivative thereof, a sulphite ion and a hygroscopic agent.
An element for determining the amount of formaldehyde present in a gaseous environment comprising (1) a formaldehyde-impermeable support having thereon a formaldehyde-sensitive layer comprising gelatin, pararosaniline hydrochloride, an alkali metal sulphite, and a hygroscopic agent;
- and (2) a strippable, formaldehyde-impermeable layer contiguous with the gelatin layer which can be removed from the gelatin layer prior to exposure.
A method for determining the quantity of formaldehyde present in a gaseous environment comprising:
- exposing a test strip to a formaldehyde-containing gaseous environment, said test strip comprising a support having thereon a formaldehyde-sensitive layer comprising gelatin, pararosaniline or an acid derivative thereof, and sulphite ion, the exposed test strip producing a dye in the formaldehyde-sensitive layer in proportion to the concentration of formaldehyde in the environment and the exposure time;
- and
- determining the quantity of formaldehyde present from the density of the dye produced.
Dependencies are inferred from the claim text.