UV fluorometric sensor and method for using the same

• US 8,084,756 B2
• Filed: 07/01/2011
• Issued: 12/27/2011
• Est. Priority Date: 06/01/2006
• Status: Active Grant

• Current Assignee: Ecolab, Inc.
• Original Assignee: Ecolab, Inc.
• Inventors: Tokhtuev, Eugene, Owen, Christopher J., Slobodyan, Viktor, Skirda, Anatoly, Schilling, Paul, Pilipchenko, Anna, Kraus, Paul R., Sanville, Katherine M., Erickson, Joseph Phillip
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): BOOSALIS, FANI POLYZOS
• Application Number:
  US13/175,491
• Publication Number:
  US 20110260079A1
• Time in Patent Office: 179 Days
• Field of Search: 250/461.1, 250/564, 250/253, 250/301, 250/573, 250/459.1, 250/372, 250/373, 356/51, 359/361
• US Class Current: 250/461.1
• CPC Class Codes: G01N 21/6402 Atomic fluorescence; Laser induced fluorescence
• CPC Class Codes: G01N 21/8507 Probe photometers, i.e. with optical measuring part dipped into fluid sample
• CPC Class Codes: G01N 33/18 Water

Abstract

An ultraviolet (UV) fluorometric sensor measures a chemical concentration in a sample based on the measured fluorescence of the sample. The sensor includes a controller, at least one UV light source, and at least one UV detector. The sensor emits UV light in a wavelength range of 245-265 nm from the light source through the sample in an analytical area. The UV detector measures the fluorescence emission from the sample. The controller transforms output signals from the UV detector into fluorescence values or optical densities for one or more wavelengths in the wavelength range of 265-340 nm. The controller calculates the chemical concentration of the chemical in the sample based on the measured fluorescence emissions.

Claims

1. A sensor, comprising:

a sensor head having a proximal end and a distal end, the distal end defined by a first planar surface and a second surface tilted substantially 45 degrees away from the first planar surface and toward the proximal end of the sensor head, the sensor head comprising;

a light source chamber including an ultraviolet (UV) light source that emits a first UV wavelength;

a light source window positioned in the second tilted surface that transmits the first UV wavelength into an analytical area containing a sample having an unknown concentration of a chemical that exhibits fluorescent characteristics;

a detector window positioned in the second tilted surface; and

a detector chamber including a UV detector that detects fluorescence emissions of the sample at a second UV wavelength transmitted through the detector window; and

a controller that calculates the concentration of the chemical in the sample based on the detected fluorescence emission.

2. The sensor of claim 1 wherein the controller calculates the concentration of the chemical in the sample based on a calculated difference in the detected fluorescence emission of the sample and a detected fluorescence emission of a zero solution having zero concentration of the chemical.

3. The sensor of claim 1 wherein the controller calculates the concentration of the chemical in the sample based on the detected fluorescence emission of the sample and a calibration constant determined for known concentrations of the chemical.

4. The sensor of claim 1 wherein the ultraviolet (UV) light source emits the first UV wavelength along a first optical path parallel to the first planar surface.

5. The sensor of claim 1 wherein the UV detector detects fluorescence emissions of the sample received along a second optical path substantially perpendicular to the first optical path.

6. The sensor of claim 1 further comprising a temperature sensor positioned in the first planar surface of the sensor head.

7. The sensor of claim 1 wherein the second UV wavelength is at least 280 nanometers.

8. The sensor of claim 1 wherein the first UV wavelength is less than 260 nanometers.

9. The sensor of claim 1 wherein the chemical is an antimicrobial agent.

10. The sensor of claim 1 wherein the sample is a solution containing the chemical, wherein the solution is a cleaning or antimicrobial solution, and wherein the chemical is selected from the group consisting of antimicrobial agents, surfactants, solvents, hydrotropes, antiredeposition agents, dyes, corrosion inhibitors, bleaching agents and mixtures thereof.

11. The sensor of claim 1 wherein the ultraviolet light source is one of a gas discharge lamp, a mercury lamp, a deuterium lamp, a metal vapor lamp, a UV light emitting diode (LED) or a plurality of UV light emitting diodes (LEDs).

12. The sensor of claim 1 wherein the ultraviolet light source is one of a mercury low pressure lamp with main line at about 255 nm or a Krypton gas discharge lamp.

13. The sensor of claim 1 further comprising a reference detector that monitors an intensity of the UV light source.

14. The sensor of claim 1 wherein the light source window and the detector window are sapphire prismatic lenses.

15. The sensor of claim 14 wherein the sapphire prismatic lenses include a cylindrical body having a first spherical surface on one side of the cylindrical body and a flat tilted surface on another side of the cylindrical body.

16. The sensor of claim 1 wherein the chemical is a multi-quat sanitizer.

17. The sensor of claim 1 wherein the controller calculates the concentration of the chemical in the sample using the equation:

C=K_X(I^S₂₈₀/I^S₂₅₄−

I⁰₂₈₀/I⁰₂₅₄)

wherein C is a concentration of the chemical in the sample, K_X is a calibration coefficient, I^S₂₈₀ is an output signal from the UV detector for the sample, I^S₂₅₄ is an output signal from a reference detector for the sample, I⁰₂₈₀ is an output signal from the UV detector for a zero solution, I⁰₂₅₄ is an output signal from the reference detector for the zero solution, and

K_X=C_CCALIBR/(I^CALIBR₂₈₀/I^CALIBR₂₅₄−

I⁰₂₈₀/I⁰₂₅₄)

where C_CALIBR is a concentration of the chemical in a calibration solution, I^CALIBR₂₈₀ is an output signal from the UV detector for the calibration solution and I^CALIBR₂₅₄ is an output signal from the reference detector for the calibration solution.

18. The sensor of claim 1 wherein the chemical is a fluorescent tracer.

19. The sensor of claim 18 wherein the fluorescent tracer is one of 2-naphthalenesulfonic acid, Acid Yellow 7,1,3,6,8-pyrenetetrasulfonic acid sodium salt, and fluorescein.

20. The sensor of claim 1 wherein the UV detector is a UV photodiode.

21. The sensor of claim 1 wherein the second UV wavelength is in the range of 265-340 nanometers.

22. The sensor of claim 1 wherein the first UV wavelength is in the range of 245-265 nanometers.

23. A sensor, comprising:

a display unit comprising at least one of a low concentration indicator, an overdosed solution indicator, a contaminated solution indicator, a normal operation indicator, and a low solution indicator;

a sensor head having a proximal end and a distal end, the distal end defined by a first planar surface and a second surface tilted substantially 45 degrees away from the first planar surface and toward the proximal end of the sensor head, the sensor head comprising;

a light source channel including an ultraviolet (UV) light source that emits a first UV wavelength;

a light source window positioned in the second tilted surface that transmits the first UV wavelength into an analytical area containing a sample having an unknown concentration of a chemical that exhibits fluorescent characteristics;

a detector window positioned in the second tilted surface;

a detector channel including a UV detector that detects fluorescence emissions of the sample at a second UV wavelength transmitted through the detector window; and

a temperature sensor positioned in the first planar surface of the sensor head that detects the temperature of the sample; and

a controller that calculates the concentration of the chemical in the sample based on the detected fluorescence emission.

24. The sensor of claim 23 wherein the light source channel includes a first optical path substantially parallel to the first planar surface.

25. The sensor of claim 24 wherein the ultraviolet (UV) light source emits the first UV wavelength along the first optical path.

26. The sensor of claim 23 wherein the detector channel includes a second optical path substantially perpendicular to the first planar surface.

27. The sensor of claim 26 wherein the UV detector detects fluorescence emissions of the sample received along the second optical path.

28. The sensor of claim 23 wherein the controller calculates the concentration of the chemical in the sample based on a calculated difference in the detected fluorescence emission of the sample and a detected fluorescence emission of a zero solution having zero concentration of the chemical.

29. The sensor of claim 23 wherein the controller calculates the concentration of the chemical in the sample based on the detected fluorescence emission of the sample and a calibration constant determined for known concentrations of the chemical.

30. The sensor of claim 23 wherein the sample is a solution containing the chemical, wherein the solution is a cleaning or antimicrobial solution, and wherein the chemical is selected from the group consisting of antimicrobial agents, surfactants, solvents, hydrotropes, antiredeposition agents, dyes, corrosion inhibitors, bleaching agents and mixtures thereof.