Analytical element having improved spreading zone and method of use

Claim 2

A dry element for the analysis or transport of an aqueous liquid comprising an isotropically porous zone which comprises a blush polymer having dispersed therein a particulate material, the element characterized by having in the porous zone a nonpolymeric heterocyclic, aliphatic or carbocyclic quaternary ammonium compound having at least 12 carbon atoms therein, which compound is present in the zone in an amount of at least 2 weight percent,-based on the dry weight of the blush polymer.

Claim 3

The element as claimed in claim 1 wherein the porous zone is carried on a support and the element comprises an interactive composition for an analyse.

Claim 4

A method for the determination of an analyte in an aqueous liquid comprising the steps of: A. physically contacting a sample of the liquid together with an interactive composition for the analyte and the dry analytical element as claimed in either claim 1 or 2 to provide a detectable change, and B. measuring the detectable change.

Claim 5

The invention as claimed in any of claims 1 to 3 wherein the quaternary ammonium compound is represented by the structures (Ia and b): wherein represents a single or double bond, R 1 , R 2 , R 3 and R 4 are independently alkyl of 1 to 30 carbon atoms, wherein the alkylene comprises 2 to 6 carbon atoms and n is an integer of 1 to 50, aryl of 6 to 14 carbon atoms, cycloalkyl of 5 to 20 carbon atoms, alkaryl of 7 to 30 carbon atoms, or a fluorocarbon group of 1 to 30 carbon atoms, provided that R 1 , R 2 , R 3 and R 4 together comprise at least 12 carbon atoms, or R 1 and R 2 , taken together with the nitrogen atom, form a quaternary heterocyclic ring and R 3 and R 4 are as defined above and comprise together at least 12 carbon atoms, or R 1 , R 2 and R 3 , taken together with the nitrogen atom, form a quaternary heterocyclic ring and R 4 is as defined above and comprises at least 12 carbon atoms, and X- is a monovalent anion.

Claim 6

The invention as claimed in claim 4 wherein R 1 is alkyl of 1 to 6 carbon atoms, R 2 is alkyl of 1 to 6 carbon atoms or (alkylene-oxy) n -H wherein the alkylene comprises 2 to 4 carbon atoms, and X - is halide or nitrate.

Claim 7

The invention as claimed in claim 4 wherein the quaternary ammonium compound is a heterocyclic amine represented by the structure (Ib) wherein R 1 , R 2 and R 3 , taken together with the nitrogen atom, complete a 5 to 20-membered quaternary heterocyclic ring.

Claim 8

The invention as claimed in any of claims 1 to 6 wherein the quaternary ammonium compound is selected from the group consisting of: wherein n is 8, 25 or 41, wherein R' is alkyl of 12, 14 or 16 carbon atoms, and wherein R" is alkyl of 8 to 18 carbon atoms, x and y are independently integers of 2 to 50.

Claim 9

The invention as claimed in any of claims 1 to 7 wherein the quaternary ammonium compound is or wherein n is 8 or 25.

Claim 10

The invention as claimed in any of claims 1 to 8 wherein the quaternary ammonium compound is present in the porous zone in an amount of from 8 to 30 weight percent, based on the dry weight of the blush polymer.

Claim 11

The invention as claimed in any of claims 1 to 9 wherein the porous zone comprises titanium dioxide or barium sulfate in cellulose acetate, and the element comprises an interactive composition for either alanine aminotransferase or aspartate aminotransferase.