UV fluorometric sensor and method for using the same

• US 7,652,267 B2
• Filed: 05/06/2009
• Issued: 01/26/2010
• Est. Priority Date: 06/01/2006
• Status: Active Grant

• Current Assignee: Ecolab, Inc.
• Original Assignee: Ecolab, Inc.
• Inventors: Tokhtuev, Eugene T., Kraus, Paul R., Owen, Christopher J., Pilipchenko, Anna, Erickson, Joseph Phillip, Skirda, Anatoly, Schilling, Paul, Slobodyan, Viktor, Sanville, Katherine M.
• Primary Examiner(s): Porta; David P
• Assistant Examiner(s): BOOSALIS, FANI POLYZOS
• Application Number:
  US12/436,593
• Publication Number:
  US 20090212236A1
• Time in Patent Office: 265 Days
• Field of Search: 250/461.1, 250/564, 250/253, 250/301, 250/573, 250/459.1, 356/51
• 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 90 degree cutout defining a first planar surface intersecting at 90 degrees to a bottom surface of the sensor head and defining a second planar surface parallel to the bottom surface and intersecting at 90 degrees to a lateral surface 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 first planar 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 planar 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 further comprising a second UV detector that detects reference fluorescence emissions of the sample at the first UV wavelength.

5. The sensor of claim 1 wherein the second UV wavelength is in a range of 280 nanometers+15 nanometers.

6. The sensor of claim 1 wherein the first UV wavelength is approximately 254 nanometers.

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

8. 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.

9. 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).

10. 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.

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

12. The sensor of claim 1 wherein the light source window includes one of a first prismatic window or a first ball lens and the detector window includes one of a second prismatic window or a second ball lens.

13. The sensor of claim 1 further comprising at least one of a reference detector, a turbidity detector, a temperature detector, an oxidation reduction potential detector, a pH detector, a conductivity detector and an electro chemical detector.

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

15. 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 first detector for the sample, I^S₂₅₄ is an output signal from the second detector for the sample, I⁰₂₈₀ is an output signal from the first detector for a zero solution (i.e., a solution with zero concentration of the chemical), I⁰₂₅₄ is an output signal from the second 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 first detector for the calibration solution and I^CALIBR₂₅₄ is an output signal from the second detector for the calibration solution.

16. The sensor of claim 1 wherein the controller further calculates a turbidity of the sample.

17. The sensor of claim 1 wherein the detector chamber further includes a second UV detector that detects scattered UV radiation of the sample at the first UV wavelength transmitted through the detector window, and the controller further calculates a turbidity of the sample based on the detected scattered UV radiation.

18. The sensor of claim 1 wherein the detector chamber further includes a dichroic mirror that separates the fluorescence emissions of the sample at the second UV wavelength transmitted through the detector window from scattered UV radiation at the first UV wavelength transmitted through the detector window.

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

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

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

22. A sensor, comprising:

a sensor head having a 90 degree cutout defining a first planar surface intersecting at 90 degrees to a bottom surface of the sensor head and defining a second planar surface parallel to the bottom surface and intersecting at 90 degrees to a lateral surface 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 planar 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 first planar 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.

23. The sensor of claim 22 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.

24. The sensor of claim 22 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.

25. The sensor of claim 22 further comprising a second UV detector that detects reference fluorescence emissions of the sample at the first UV wavelength.

26. The sensor of claim 22 wherein the second UV wavelength is in a range of 280 nanometers+15 nanometers.

27. The sensor of claim 22 wherein the first UV wavelength is approximately 254 nanometers.

28. The sensor of claim 22 wherein the chemical is an antimicrobial agent.

29. The sensor of claim 22 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.

30. The sensor of claim 22 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).

31. The sensor of claim 22 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.

32. The sensor of claim 22 further comprising a second UV detector that monitors an intensity of the UV light source.

33. The sensor of claim 22 wherein the light source window includes one of a first prismatic window or a first ball lens and the detector window includes one of a second prismatic window or a second ball lens.

34. The sensor of claim 22 further comprising at least one of a reference detector, a turbidity detector, a temperature detector, an oxidation reduction potential detector, a pH detector, a conductivity detector and an electro chemical detector.

35. The sensor of claim 22 wherein the chemical is a multi-quat sanitizer.

36. The sensor of claim 22 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 first detector for the sample, I^S₂₅₄ is an output signal from the second detector for the sample, I⁰₂₈₀ is an output signal from the first detector for a zero solution (i.e., a solution with zero concentration of the chemical), I⁰₂₅₄ is an output signal from the second 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 first detector for the calibration solution and I^CALIBR₂₅₄ is an output signal from the second detector for the calibration solution.

37. The sensor of claim 22 wherein the controller further calculates a turbidity of the sample.

38. The sensor of claim 22 wherein the detector chamber further includes a second UV detector that detects scattered UV radiation of the sample at the first UV wavelength transmitted through the detector window, and the controller further calculates a turbidity of the sample based on the detected scattered UV radiation.

39. The sensor of claim 22 wherein the detector chamber further includes a dichroic mirror that separates the fluorescence emissions of the sample at the second UV wavelength transmitted through the detector window from scattered UV radiation at the first UV wavelength transmitted through the detector window.

40. The sensor of claim 39 wherein the fluorescent tracer is one of 2-naphthalenesulfonic acid, Acid Yellow 7,1,3,6,8-pyrenetetrasulfonic acid sodium salt, and fluorescein.