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1. US20110299076 - Spectrometer with validation cell

Anmerkung: Text basiert auf automatischer optischer Zeichenerkennung (OCR). Verwenden Sie bitte aus rechtlichen Gründen die PDF-Version.

[ EN ]

Claims

1. An analytical system comprising:
a validation cell positioned such that light generated by a light source passes through the validation cell at least once in transmission of the light from the light source to a detector, the validation cell containing a reference gas comprising a known amount of an analyte compound, the light source emitting the light in a wavelength range that comprises a spectral absorbance feature of the analyte compound; and
a controller to perform an instrument validation process and a sample analysis process, the instrument validation process comprising:
receiving first light intensity data that quantify a first intensity of the light received at the detector while the light passes at least once through each of the reference gas in the validation cell and a zero gas having at least one of known and negligible first light absorbance characteristics that overlap second light absorbance characteristics of the analyte compound within the wavelength range, and
verifying a valid state of the analytical system by determining that the first light intensity data do not deviate from a stored data set that by greater than a pre-defined threshold deviation, the stored data set representing at least one previous measurement collected during a previous instrument validation process performed on the analytical system; and
the sample analysis process comprising:
receiving second light intensity data that quantify a second intensity of the light received at the detector while the light passes at least once through each of the reference gas in the validation cell and a sample gas containing an unknown concentration of the analyte compound, and
determining a concentration of the analyte compound in the sample gas by correcting the second light intensity data to account for a known absorbance of the light in the validation cell.
2. An apparatus as in claim 1, further comprising a sample measurement cell to contain an analysis volume, the analysis volume containing the sample gas during the sample analysis process and the zero gas during the instrument validation process, the sample measurement cell being positioned such that the light passes at least once through each of the analysis volume in the sample measurement cell and the reference gas in the validation cell during transmission of the light from the light source to the detector.
3. An apparatus as in claim 2, further comprising a flow switching apparatus activated by the controller to admit the sample gas into the analysis volume of the sample measurement cell during the sample analysis process and to admit the zero gas into the analysis volume of the sample measurement cell during the instrument validation process.
4. An apparatus as in claim 2, wherein the validation cell comprises a light transmissive optical surface through which the light passes, the light transmissive optical surface forming at least part of the validation cell.
5. An apparatus as in claim 2, wherein the sample measurement cell comprises a light reflective optical surface upon which the light impinges and is at least partially reflected, the light reflective optical surface forming at least part of the sample measurement cell.
6. An apparatus as in claim 2, further comprising: an integrated optical cell that comprises the validation cell and the sample measurement cell.
7. An apparatus as in claim 6, wherein the integrated optical cell comprises a multipass cell comprising a first reflective optical surface and a second optical reflective surface, each reflecting the light at least once, and wherein the validation cell is contained between at least part of the first reflective optical surface and a transmissive optical surface disposed between the first reflective optical surface and the second optical reflective surface and a light transmissive surface disposed before the first reflective surface.
8. An apparatus as in claim 6, wherein the integrated optical cell comprises a multipass cell comprising a first reflective optical surface and a second reflective optical surface, each reflecting the light at least once, and wherein the validation cell is contained before at least part of the first reflective optical surface and a transmissive optical surface disposed before the first reflective surface.
9. An apparatus as in claim 2, wherein at least one of the validation cell and the sample measurement cell is contained within a hollow core optical light guide hermetically sealed on a first end by a first light-transmissive optical element allowing the light to enter the hollow optical light guide and hermetically sealed on an opposite end by a second light transmissive optical element allowing the light to exit the hollow core optical light guide.
10. An apparatus as in claim 2, wherein at least one of the validation cell and the sample measurement cell is integral to a hermetically sealed laser package from which the light is transmitted via at least one transmissive optical element that forms a seal to the hermetically sealed laser package.
11. An apparatus as in claim 1, further comprising at least one of a temperature sensor that determines a temperature in the validation cell and a pressure sensor that determines a pressure in the validation cell; and wherein the operations performed by the controller further comprise:
receiving at least one of the temperature and the pressure; and
adjusting the known absorbance of the light in the validation cell based on the one or more of the temperature and the pressure as part of determining the concentration of the analyte in the sample gas.
12. An apparatus as in claim 1, wherein the path of the light passes through a free gas space at least once in traversing between the light source and the detector; and wherein the flow switching apparatus admits the sample gas into the free gas space during the sample analysis mode and admits the zero gas into the free gas space during the validation mode.
13. An apparatus as in claim 12, wherein the validation cell is integral to a first reflector positioned on a first side of the free gas space and the path of the light reflects at least once off of each of the first reflector and a second reflector positioned on a opposite side of the free gas space in traversing between the light source and the detector.
14. An apparatus as in claim 1, further comprising a temperature control system that maintains a temperature in the validation cell at a preset value.
15. An apparatus as in claim 1, wherein the validation cell comprises one of a sealed container pre-loaded with the reference gas and a flow-through cell through which the reference gas is passed.
16. A method comprising:
receiving first light intensity data that quantify a first intensity of light received at a detector from a light source after the light has passed at least once through each of a reference gas in a validation cell and a zero gas, the reference gas comprising a known amount of an analyte compound, the light source emitting the light in a wavelength range that comprises a spectral absorbance feature of the analyte compound, the zero gas having at least one of known and negligible first light absorbance characteristics in the wavelength range;
verifying a valid state of an analytical system comprising the light source and the detector by determining that the first light intensity data do not deviate from a stored data set by greater than a pre-defined threshold deviation, the stored data set representing at least one previous measurement collected during a previous instrument validation process performed on the analytical system;
receiving second light intensity data that quantify a second intensity of the light received at the detector from the light source after the light passes at least once through each of the reference gas in the validation cell and a sample gas containing an unknown concentration of the analyte compound; and
determining, using a system comprising a programmable processor, a concentration of the analyte compound in the sample gas by correcting the second light intensity data to account for a known absorbance of the light in the validation cell.
17. A method as in claim 16, further comprising:
measuring one or more of a temperature in the validation cell and a pressure in the validation cell; and
adjusting the absorbance of the light in the validation cell based on the one or more of the temperature and the pressure as part of determining the concentration of the analyte in the sample gas.
18. A method as in claim 16, wherein the zero gas comprises at least one of a noble gas, nitrogen gas, oxygen gas, air, hydrogen gas, a homo-nuclear diatomic gas, at least a partial vacuum, a hydrocarbon gas, a fluorocarbon gas, a chlorocarbon gas, carbon monoxide gas, and carbon dioxide gas.
19. A method as in claim 16, further comprising: passing the zero gas through at least one of a scrubber and a chemical converter to remove or reduce a concentration of the trace analyte therein before directing the zero gas into the path of the light.
20. A computer-readable medium comprising machine instructions that, when executed by at least one programmable processor, cause the at least one programmable processor to perform operations comprising:
receiving first light intensity data that quantify a first intensity of light received at a detector from a light source after the light has passed at least once through each of a reference gas in a validation cell and a zero gas, the reference gas comprising a known amount of an analyte compound, the light source emitting light in a wavelength range that comprises a spectral absorbance feature of the analyte compound, the zero gas having at least one of known and negligible first light absorbance characteristics in the wavelength range;
verifying a valid state of an analytical system comprising the light source and the detector by determining that the first light intensity data do not deviate from a stored data set by greater than a pre-defined threshold deviation, the stored data set representing at least one previous measurement collected during a previous instrument validation process performed on the analytical system;
receiving second light intensity data that quantify a second intensity of the light received at the detector from the light source after the light passes at least once through each of the reference gas in the validation cell and a sample gas containing an unknown concentration of the analyte compound; and
determining a concentration of the analyte compound in the sample gas by correcting the second light intensity data to account for a known absorbance of the light in the validation cell.
21. An apparatus as in claim 2, wherein the validation cell comprises a light reflective optical surface upon which the light impinges and is at least partially reflected, the light reflective optical surface forming at least part of the validation cell.
22. An apparatus as in claim 2, wherein the sample measurement cell comprises a light transmissive optical surface through which the light passes, the transmissive optical surface forming at least part of the sample measurement cell.