Electroanalytical applications of screen-printable surfactant-induced sol-gel graphite composites

• US 6,231,920 B1
• Filed: 10/29/1998
• Issued: 05/15/2001
• Est. Priority Date: 10/29/1997
• Status: Expired due to Term

• Current Assignee: University of Puerto Rico
• Original Assignee: University of Puerto Rico
• Inventors: Guadalupe, Ana R., Guo, Yizhu
• Primary Examiner(s): PARKER, FREDERICK JOHN
• Application Number:
  US09/181,875
• Time in Patent Office: 929 Days
• Field of Search: 427/2.11, 427/58, 427/122, 427/282, 427/287, 204/403, 204/294, 600/372, 252/510, 252/511
• US Class Current: 427/122
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: G01N 27/308 at least partially made of carbon
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001

Abstract

A process for preparing sol-gel graphite composite electrodes is presented. This process preferably uses the surfactant bis(2-ethylhexyl) sulfosuccinate (AOT) and eliminates the need for a cosolvent, an acidic catalyst, a cellulose binder and a thermal curing step from prior art processes. Fabrication of screen-printed electrodes by this process provides a simple approach for electroanalytical applications in aqueous and nonaqueous solvents. Examples of applications for such composite electrodes produced from this process include biochemical sensors such as disposable, single-use glucose sensors and ligand modified composite sensors for metal ion sensitive sensors.

Claims

1. A method for preparing a surfactant-induced, sol-gel graphite composite electrode, said method comprising the steps of:

mixing an aqueous solution of the surfactant with a silane or a siloxane to obtain a clear and homogeneous sol solution, wherein said mixing is performed in the absence of a co-solvent, a catalyst, or a cellulose binder;

mixing said sol solution with graphite powder to form a uniform and free-flowing paste; and

applying said paste onto a substrate to form at least one electrode;

wherein a thermal curing process step is not required.

2. The method of claim 1, wherein the graphite powder is mixed with a buffer solution or an alcohol solution containing a modifier or recognition entity for an analyte, wherein said modifier or recognition entity is chosen according to the analyte to be determined, and dried prior to being mixed with the sol solution.

3. The method of claim 2, wherein the buffer solution or alcohol solution comprises ferrocene and glucose oxidase.

4. The method of claim 2, wherein the alcohol solution is an ethanol solution.

5. The method of claim 1, wherein the substrate is PVC, a ceramic, a metal, or a glass.

6. The method of claim 1, wherein the silane or siloxane is tetramethyl orthosilicate, methyltrimethoxysilane, tetraethoxysilane, or methyltriethoxysilane, and the surfactant is surfactant bis(2-ethylhexyl) sulfosuccinate, octylphenol ethylene oxide condensate, cetyltrimethylammonium bromide, or sodium dodecylsulfate.

7. The method of claim 6, wherein the siloxane is tetramethylorthosilicate and the surfactant is surfactant bis(2-ethylhexyl) sulfosuccinate.

8. The method of claim 1, wherein the paste is applied onto the substrate to form at least one electrode by screen printing.