ZWITTERION BUFFER CONTAINING COMPOSITIONS AND USES IN ELECTROANALYTICAL METHODS
Described herein are reagent compositions for detecting and/or measuring analytes in a test sample. In one embodiment, reagent compositions are described for detecting and/or measuring glucose in a sample.
1 . A dried reagent composition comprising (a) one or more enzymes selected from the group consisting of glucose dehydrogenases (GDH), glucose oxidoreductases, and combinations thereof; (b) one or more co-factors, co-enzymes, or a combination thereof for the one or more enzymes; (c) one or more mediators, mediator precursors, or a combination thereof; (d) one or more zwitterionic buffers; and (e) optionally one or more adjuvants.
2 . The reagent composition of claim 1 wherein the enzyme is a wild-type GDH, a mutant GDH, or a GDH coenzyme.
3 . The reagent composition of claim 1 wherein the GDH coenzyme is a FAD-GDH or a PQQ-GDH.
4 . The reagent composition of claim 1 wherein the enzyme is a mutant GDH exhibiting maltose insensitivity.
5 . The reagent composition of claim 1 wherein the enzyme is a mutant GDH exhibiting thermal stability.
6 . The reagent composition of claim 1 wherein the zwitterionic buffer is PIPES or MOPS.
7 . The reagent composition of claim 1 wherein the composition comprises a mediator precursor.
8 . The reagent composition of claim 1 wherein the mediator precursor is a nitrosoaniline.
9 . The reagent composition of claim 1 wherein the one or more adjuvants are selected from the group consisting of additional buffers, stabilizers, viscosity adjusting agents, film forming agents, thixotropic agents, dispersants, surfactants, detergents, pH adjusting agents, and combinations thereof.
10 . The reagent composition of claim 1 wherein at least one adjuvant is a film former.
11 . The reagent composition of claim 10 wherein the film former is a polyvinyl acetate propionate co-polymer, polyvinyl propionate dispersions, or polyvinylpyrrolidone, or a combination thereof.
12 . The reagent composition of claim 1 wherein at least one adjuvant is a viscosity modulator.
13 . The reagent composition of claim 12 wherein the viscosity modulator a hydroxymethylcellulose, hydroxyethylcelluiose, methyihydroxyethylcellulose, or xanthan gum, or a combination thereof.
14 . The reagent composition of claim 1 wherein at least one adjuvant is a dispersant.
15 . The reagent composition of claim 14 wherein the dispersant is a silica.
16 . The reagent composition of claim 1 wherein at least one adjuvant is an additional buffer.
17 . The reagent composition of claim 16 wherein the additional buffer is a beta-glycerophosphate.
18 . An electrochemical cell comprising the reagent composition of claim 1 and an electrode.
19 . A test strip having a chamber, where the reagent composition of claim 1 and an electrode are located in the chamber.
20 . The test strip of claim 19 wherein the chamber is formed from a base substrate and a covering layer overlying the base substrate; and where the chamber is disposed between the base substrate and the covering layer.
21 . The test strip of claim 19 wherein the chamber includes a flared portion terminating in a fluid receiving opening and an elongated portion extending inwardly from the flared portion
22 . The test strip of claim 19 further comprising a vent in communication with the chamber, whereby air can escape from the vent as fluid is drawn into the chamber.
23 . The test strip of claim 19 wherein the chamber has a volume less than or equal to 1.0 μL.
24 . The test strip of claim 23 wherein the chamber has a volume less than or equal to 0.5 μL.