Photoelectric chemical sensor and sensing method utilizing interfacial photo-voltages

• US 20080277590A1
• Filed: 04/07/2008
• Published: 11/13/2008
• Est. Priority Date: 11/08/2000
• Status: Active Grant

• Current Assignee: Jay S. Huebner, Rodolfo T. Arrieta
• Original Assignee: Jay S. Huebner, Rodolfo T. Arrieta
• Inventors: Huebner, Jay S., Arrieta, Rodolfo T.
• Granted Patent: US 8,354,647 B2
• Time in Patent Office: Days
• US Class Current: 250/393
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G01N 27/305 optically transparent or photoresponsive electrodes

Abstract

A device and method which comprises a sensing surface on a membrane, solid surface or electrode, where the sensing surface contains a photo-voltage active material chosen in relation to a particular target substance to be detected and quantified. The photo-voltage active material is of a type which produces an interfacial photo-voltage electrical signal upon illumination. The particular photo-voltage active material chosen for a particular target substance is one in which the presence of the target substance causes a change in the electrical signal produced. The presence of the target substance modifies the expected photo-voltage produced by the sensing surface upon illumination. The photo-voltage produces signals which are detected by electronic circuits, and the presence and concentration of the target substance is determined by analyzing the difference between the photo-voltage of the target sample versus the photo-voltage of a control sample lacking the target substance.

Claims

1. An apparatus for detecting the presence and concentration of a target substance in a solution through comparison of the differences in interfacial photo-voltages between a control solution and a target solution containing the target substance, wherein a photo-voltage active material is utilized which produces interfacial photo-voltage upon illumination and which produces a different amount of interfacial photo-voltage upon illumination when in contact with said target substance, the apparatus comprising:

a light source for illumination;

an electrode having a photo-voltage active material adsorbed thereon which produces interfacial photo-voltage upon illumination and which produces a different amount of interfacial photo-voltage upon illumination when in contact with said target substance, said photo-voltage active material being in contact with said target solution;

a digital signal processor in electrical communication with said electrode to detect said photo-voltages and to generate a signal for analysis;

means to analyze said signal to determine the presence and concentration of said target substance.

2. The apparatus of claim 1, further comprising a container to receive a target solution containing a target substance, and wherein said electrode is disposed within said container.

3. The apparatus of claim 1, wherein said light source is chosen from the group of light sources consisting of lasers, stroboscopes and LEDs.

4. The apparatus of claim 1, wherein said electrode comprises a self-assembled monolayer.

5. The apparatus of claim 1, where said analyzer means is an oscilloscope.

6. The apparatus of claim 2, further comprising additional electrodes disposed within said container, each said electrode having a photo-voltage active material adsorbed thereon which produces interfacial photo-voltage upon illumination and which produces a different amount of interfacial photo-voltage upon illumination when in contact with said target substance, said photo-voltage active material being in contact with said target solution.

7. The apparatus of claim 6, wherein each of said adsorbed photo-voltage active materials on said electrode and said additional electrodes is a different photo-voltage active material.

8. A method for detecting the presence of a target substance in a solution comprising the steps of:

providing a sensing device to sense the interfacial photo-voltage resulting from illumination of a photo-voltage active material deposited onto an electrode and which is in contact with said target substance;

placing said target substance in contact with said photo-voltage active material;

illuminating said photo-voltage active material;

detecting and analyzing said photo-voltage.

9. The method of claim 8, further comprising the steps of:

choosing a photo-voltage active material which produces photo-voltage upon illumination and which produces a different amount of photo-voltage upon illumination when in contact with said target substance.

10. The method of claim 8, further comprising the steps of:

detecting and analyzing the photo-voltage resulting from illumination of said photo-voltage active material when not in contact with said target substance;

comparing the results from illumination of said photo-voltage active material when not in contact with said target substance to the results obtained from illumination of said photo-voltage active material when in contact with said target substance.

11. The method of claim 10, further comprising the steps of:

successively detecting and analyzing the photo-voltage resulting from illumination of said photo-voltage active material when in contact with different concentrations of said target substance;

comparing the results from illumination of said photo-voltage active material when in contact with said target substance to the results obtained from illumination of said photo-voltage active material when in contact with different concentrations of said target substance to determine the concentration of said target substance.

12. The method of claim 10, wherein said photo-voltage active material is a first photo-voltage active material and said target substance is a first target substance, and further comprising the steps of:

providing at least one different photo-voltage active material from said first photo-voltage active material and adsorbing said at least one different photo-voltage active material onto a different electrode, wherein said at least one different photo-voltage active material produces interfacial photo-voltage upon illumination and which produces a different amount of photo-voltage upon illumination when in contact with said different target substance;

placing said different target substance in contact with said at least one different photo-voltage active material simultaneously with placing said first target substance in contact with said first photo-voltage active material;

illuminating said at least one different photo-voltage active material simultaneously with illuminating said first photo-voltage active material;

detecting and analyzing said photo-voltage from said at least one different photo-voltage active material.

13. A method for detecting the presence of a target substance in a solution comprising the steps of:

providing a sensing device to sense the photo-voltage resulting from illumination of a photo-voltage active material which is in contact with said target substance;

choosing a photo-voltage active material which produces photo-voltage upon illumination and which produces a different amount of photo-voltage upon illumination when in contact with said target substance;

adsorbing said photo-voltage active material onto an electrode;

illuminating said photo-voltage active material;

detecting and analyzing the photo-voltage resulting from illumination of said photo-voltage active material when not in contact with said target substance to provide a baseline value;

placing said target substance in solution in contact with said photo-voltage active material;

illuminating said photo-voltage active material;

detecting and analyzing the photo-voltage resulting from illumination of said photo-voltage active material when in contact with said target substance;

comparing the baseline value results from illumination of said photo-voltage active material when not in contact with said target substance to the results obtained from illumination of said photo-voltage active material when in contact with said target substance to determine if said target substance is present.

14. The method of claim 13, further comprising the steps of:

successively detecting and analyzing the photo-voltage resulting from illumination of said photo-voltage active material when in contact with different concentrations of said target substance to produce comparative concentration values;

comparing the results from illumination of said photo-voltage active material when in contact with said target substance to the comparative concentration value results obtained from illumination of said photo-voltage active material when in contact with different concentrations of said target substance to determine the concentration of said target substance.

15. The method of claim 13, wherein said photo-voltage active material is a first photo-voltage active material and said target substance is a first target substance, further comprising the steps of:

providing at least one different photo-voltage active material from said first photo-voltage active material and adsorbing said at least one different photo-voltage active material onto a different electrode, wherein said at least one different photo-voltage active material produces interfacial photo-voltage upon illumination and which produces a different amount of photo-voltage upon illumination when in contact with a different target substance;

placing said different target substance in contact with said at least one different photo-voltage active material simultaneously with placing said first target substance in contact with said first photo-voltage active material;

illuminating said at least one different photo-voltage active material simultaneously with illuminating said first photo-voltage active material;

detecting and analyzing said photo-voltage from said at least one different photo-voltage active material.

16. The method of claim 13, wherein said photo-voltage active material is a first photo-voltage active material and said target substance is a first target substance, further comprising the steps of:

successively detecting and analyzing the photo-voltage resulting from illumination of said first photo-voltage active material when in contact with different concentrations of said first target substance to produce comparative concentration values;

comparing the results from illumination of said first photo-voltage active material when in contact with said first target substance to the comparative concentration value results obtained from illumination of said first photo-voltage active material when in contact with different concentrations of said first target substance to determine the concentration of said first target substance

providing at least one different photo-voltage active material from said first photo-voltage active material and adsorbing said at least one different photo-voltage active material onto an electrode, wherein said at least one different photo-voltage active material produces photo-voltage upon illumination and which produces a different amount of photo-voltage upon illumination when in contact with a different target substance;

placing said different target substance in contact with said at least one different photo-voltage active material simultaneously with placing said first target substance in contact with said first photo-voltage active material;

illuminating said at least one different photo-voltage active material simultaneously with illuminating said first photo-voltage active material;

detecting and analyzing said photo-voltage from said at least one different photo-voltage active material;

successively detecting and analyzing the photo-voltage resulting from illumination of said at least one different photo-voltage active material when in contact with different concentrations of said different target substance to produce comparative concentration values;

comparing the results from illumination of said at least one different photo-voltage active material when in contact with said different target substance to the comparative concentration value results obtained from illumination of said at lest one different photo-voltage active material when in contact with different concentrations of said different target substance to determine the concentration of said different target substance.