IN-SITU SOIL NITRATE ION CONCENTRATION SENSOR

• US 20110242530A1
• Filed: 03/28/2011
• Published: 10/06/2011
• Est. Priority Date: 11/09/2007
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Kamal, Tamir, Hopmans, Jan W., Shaw, Benjamin D., Tuli, Atac
• Granted Patent: US 8,444,937 B2
• Time in Patent Office: Days
• US Class Current: 356/300
• CPC Class Codes: G01N 2033/245 for agricultural purposes
• CPC Class Codes: G01V 9/00 Prospecting or detecting by methods not provided for in groups G01V1/00 - G01V8/00
• CPC Class Codes: Y10T 436/173076 Nitrite or nitrate
• CPC Class Codes: Y10T 436/25375 Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]

Abstract

A method and apparatus for near real-time in-situ soil solution measurements is presented. An outer sleeve is placed in soil where ionic concentrations of organic or inorganic species are to be measured. A porous section connects with the outer sleeve (the porous section initially loaded with distilled water) equilibrates with the solution present in soil pores to form a solution to be measured. The initial distilled water is displaced within the porous section by a removable plunger. After substantial equilibration of the solution to be measured within the apparatus, the plunger is removed and a removable probe replaced. The probe may be an Ion Selective Electrode, or a transflection dip probe. The probe then may be used under computer control for measurement of solution properties. The Ion Selective Electrode may measure nitrate (NO₃⁻) concentrations. The transflection dip probe may be read with spectrometer with an input deuterium light source.

Claims

1-26. -26. (canceled)

27. An in-situ ion measurement system, comprising:

a probe body having a central bore and a distal porous section with pores sized to allow diffusion and bulk fluid flow therethrough;

a plunger disposed in the central bore of the probe body configured to bring a volume of distilled water within the central bore in contact with the porous section of the probe body and equilibrate with a soil solution in soil surrounding the probe body and produce a measurement solution; and

a probe placed within the central bore of the probe body, wherein a sensitive portion of the probe measures at least one characteristic of the measurement solution.

28. The in-situ ion measurement system as recited in claim 27, wherein the probe is an Ion Selective Probe.

29. The in-situ ion measurement system as recited in claim 27, wherein the probe is a nitrate Ion Selective Probe.

30. The in-situ ion measurement system as recited in claim 27, wherein the probe is an optical probe.

31. The in-situ ion measurement system as recited in claim 30, wherein the probe is a transflection dip probe.

32. The in-situ ion measurement system as recited in claim 31, wherein the transflection dip probe allows absorption of an input light source as the input light passes through the measurement solution into an output signal.

33. The in-situ ion measurement system as recited in claim 30, further comprising:

a deuterium light source that provides an input light source;

an optical spectrometer that measures an output signal from the passage of the input light source through the measurement solution.

34. The in-situ ion measurement system as recited in claim 33, further comprising:

a computer that controls a collection of in-situ measurements through the spectrometer.

35. The in-situ ion measurement system as recited in claim 34, wherein the in-situ spectrometer measurements are ion concentration measurements.

36. The in-situ ion measurement system as recited in claim 34, wherein the in-situ spectrometer measurements are nitrate ion concentration measurements.

37. The in-situ ion measurement system as recited in claim 34, wherein the in-situ spectrometer measurements are measured on one or more components of BTEXS concentration measurements.

38. The in-situ ion measurement system as recited in claim 37, wherein BTEXS comprises one or more of a contaminant selected from a group of contaminants consisting of:

benzene, toluene, ethyl benzene, xylene, and styrene.

39. The in-situ ion measurement system as recited in claim 33, wherein the in-situ spectrometer measurements are measured on one or more of a contaminant selected from a group of contaminants consisting of:

a polychlorinated biphenyl, tetrachloroethylene, sulfur dioxide, arsenic, selenium, petroleum, petroleum distillates, petroleum byproducts, hydrocarbon, pentachlorophenol, creosote, a pesticide, a polycyclic aromatic hydrocarbon (PAH), a volatile organic carbon (VOC), a dioxin, a dibenzofuran, copper, lead, zinc, hexavalent chromium(VI), cadmium, and mercury.

40. An in-situ measurement system, comprising:

a probe body having a central bore and a distal porous section with pores sized to allow diffusion and bulk fluid flow therethrough;

a plunger disposed in the central bore of the probe body configured to bring a volume of distilled water within the central bore in contact with the porous section of the probe body and equilibrate with a solution in material surrounding the probe body and produce a measurement solution;

a probe placed within the central bore of the probe body, wherein a sensor portion of the probe measures at least one characteristic of the measurement solution; and

a computer that controls a collection of in-situ measurements from the sensor portion of the probe.

41. The in-situ measurement system as recited in claim 40, wherein the plunger further comprises a channel coupled to a pressure measurement device, wherein the pressure of the measurement solution can be monitored.

42. The in-situ measurement system as recited in claim 40, wherein the probe comprises an Ion Selective Electrode probe.

43. The in-situ measurement system as recited in claim 40, wherein the probe comprises a transflection dip probe.

44. The in-situ measurement system as recited in claim 43, wherein the transflection dip probe is capable of measuring absorbance in the range of 200 nm through 1100 nm.

45. The in-situ measurement system as recited in claim 43, wherein the transflection dip probe is capable of measuring absorbance in the range of 235 nm through 240 nm.

46. The in-situ measurement system as recited in claim 43, wherein the transflection dip probe is capable of measuring solution absorbance at one or more of the wavelengths selected from the group of wavelengths consisting of:

235 nm, 238 nm, and 240 nm.