Ion selective electrodes for direct organic drug analysis in saliva, sweat, and surface wipes

• US 20040217017A1
• Filed: 04/26/2004
• Published: 11/04/2004
• Est. Priority Date: 10/12/2001
• Status: Active Grant

• Current Assignee: Navy The USA As Represented By The Secretary of The
• Original Assignee: Navy The USA As Represented By The Secretary of The
• Inventors: Kidwell, David A.
• Granted Patent: US 7,618,523 B2
• Time in Patent Office: Days
• US Class Current: 205/792
• CPC Class Codes: G01N 27/3335 the membrane containing at least one organic component G01N27/3271 takes precedence; aspects concerning the enzyme reagent in enzyme electrodes C12Q1/001
• CPC Class Codes: G01N 33/48714 for determining substances foreign to the organism, e.g. drugs or heavy metals drugs by chemical analysis G01N33/94

Abstract

A hand-held portable drug monitoring system to detect and quantitate cocaine and other organic drugs in saliva, sweat, and surface wipes by using an ion selective electrode or an array of ion selective electrodes. The ion selective electrode has a cast membrane reference electrode and a sensing electrode with a hydrophobic polymer, a plasticizer, and an ionophore selective for the organic drug to be tested. The ion selective electrode can be connected to a converter that coverts a voltage reading from the ion selective electrode to a quantitative drug concentration level. Also disclosed is the related method of using an ion selective electrode to detect an organic drug in saliva, sweat, and surface wipes, the method of testing electrical contact in an ion selective electrode, and the method of making a cast membrane reference electrode.

Claims

1-25. -25. (canceled)

26. A method for testing electrical continuity, comprising the steps of:

(a) injecting a voltage pulse into a reference electrode; and

(b) determining if there is a corresponding voltage pulse in a sensing electrode without drawing sufficient current in making the measurement to substantially vary the injected voltage.

27. A method of making a cast membrane reference electrode comprising the steps of:

(a) casting a membrane over a hole wherein said membrane is comprised of a hydrophilic polymer and a hydrophobic polymer;

(b) filling the interior of the hole with a solution;

(c) placing a wire into the solution; and

(d) sealing the hole;

wherein the cast membrane reference electrode results in a half-cell where the reference voltage is substantially independent of the concentration of ionic species in solution.

33. The method of claim 27 wherein said hydrophobic polymer is polyvinyl chloride.

34. The method of claim 27 wherein said hydrophilic polymer is polyethylene glycol, polyethylene glycol grafted onto a hydrophobic molecule, polypropylene glycol, or polypropylene glycol grafted onto a hydrophobic molecule.

28-29. -29. (canceled)

30. A cast membrane reference electrode comprising:

(a) a support containing a hole;

(b) a membrane cast over the hole in the support wherein said membrane is comprised of a hydrophilic polymer and a hydrophobic polymer;

(c) a solution in the interior of the hole in the support; and

(d) a wire in the solution;

wherein the cast membrane reference electrode results in a half-cell where the reference voltage is substantially independent of the concentration of ionic species in solution.

31. The cast membrane reference electrode of claim 30 wherein said hydrophobic polymer is polyvinyl chloride.

32. The cast membrane reference electrode of claim 30 wherein said hydrophilic polymer is polyethylene glycol, polyethylene glycol grafted onto a hydrophobic molecule, polypropylene glycol, or polypropylene glycol grafted onto a hydrophobic molecule.

35. A method for detecting an organic drug in saliva or from a surface swab comprising the steps of:

(a) placing an ion selective electrode in a person'"'"'s mouth, or taking saliva from a person'"'"'s mouth and placing the saliva on an ion selective electrode, or squeezing a damp surface swab onto an ion selective electrode after wiping a surface suspected of being contaminated with an organic drug, or wiping a surface after wrapping a damp surface swab around an ion selective electrode;

(b) ensuring that the ion selective electrode has electrical contact with a reference electrode; and

(c) converting a voltage from the ion selective electrode to a quantitative drug concentration level.