Analytical method and multilayer element for total ionic iron determination
AssigneeEastman Kodak Company
InventorsHarold C. Warren, III, John C. Mauck
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Abstract
A dry multilayer analytical element for determination of total ionic iron is disclosed. The element includes a dye which complexes with Fe.sup.+2. The dye has the structure ##STR1## R.sup.1 represents an electron donating group; or R.sup.1, together with the carbon to which it is attached, represents sufficient atoms to form a cyclic electron donating group fused to the phenyl group to which R.sup.1 is attached; R.sup.2 represents an electron withdrawing group; and R.sup.3 represents H, Cl, F, Br or OR.sup.4 wherein R.sup.4 represents a hydrocarbon having from 1 to 20 carbon atoms.
Claims5
A multilayer analytical element for quantitative determination of total ionic iron in an aqueous fluid comprising in the following order;
- (a) a spreading layer;
- and
- (b) a reducing layer comprising a reducing agent for Fe.sup.+3 ;
- and
- (c) a reagent layer for complexing Fe.sup.+2 iron comprising
- (i) a coupler solvent selected from the group consisting of dioctyl phenyl phosphonate and diethyl lauramide;
- (ii) a buffering composition of sufficient concentration to maintain a pH in the range of 4 to 5 when the reagent layer is contacted with an aqueous fluid and
- (iii) a dye having the structure ##STR7## R.sup.1 represents an electron donating group;
- or R.sup.1, together with the carbon to which it is attached, represents sufficient atoms to form a cyclic electron donating group fused to the phenyl group to which R.sup.1 is attached;
- R.sup.2 represents an electron withdrawing group;
- and
- R.sup.3 represents H, Cl, F, Br or OR.sup.4 wherein R.sup.4 represents a hydrocarbon having from 1 to 20 carbon atoms.
Dependencies are inferred from the claim text.