FOURIER TRANSFORM INFRARED SPECTROPHOTOMETER

• US 20070125950A1
• Filed: 10/11/2006
• Published: 06/07/2007
• Est. Priority Date: 10/14/2005
• Status: Abandoned Application

• Current Assignee: Hai-Shui Wang, Junzo Umemura
• Original Assignee: Hai-Shui Wang, Junzo Umemura
• Inventors: Wang, Hai-Shui, Umemura, Junzo
• Application Number:
  US11/548,414
• Publication Number:
  US 20070125950A1
• Time in Patent Office: Days
• US Class Current: 250/339.80
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0286 Constructional arrangements for compensating for fluctuations caused by temperature, humidity or pressure, or using cooling or temperature stabilization of parts of the device; Controlling the atmosphere inside a spectrometer, e.g. vacuum
• CPC Class Codes: G01J 3/0297 Constructional arrangements for removing other types of optical noise or for performing calibration
• CPC Class Codes: G01J 3/45 Interferometric spectrometry
• CPC Class Codes: G01N 2021/3595 using FTIR
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis

Abstract

A convenient and economical method and instrumentation to efficiently reduce offensive spectral noises due to water vapor and carbon dioxide gas often encountered in FTIR spectrophotometry is provided by spectrally monitoring and controlling the amount of water vapor and carbon dioxide gas inside the spectrophotometer such that both amounts in the sample and background measurements become congruent through remote open-close operation of water-vapor (or carbon dioxide gas) supplier and dehumidifier (or carbon dioxide gas adsorber). This new technique can be used: (1) Under the ambient humidity condition, saving time and money effectively. (2) Both in the closed spectrophotometer and in the open system. (3) And applicable to any FTIR accessory and measurement method, including transmission, external reflection, reflection-absorption, attenuated total reflection (ATR), and microscopy measurements.

Claims

1. A Fourier transform infrared spectrophotometer to reduce spectral noises due to water vapor, comprising:

a sample room in which a sample is placed,

a humidifying vessel containing a humidifying agent, which humidifies the inside of the sample room through a first door isolating the vessel and the sample room, and

a drying vessel containing a dehumidifying agent, which dehumidifies the inside of the sample room through a second door isolating the vessel and the sample room;

whereby the first door and the second door are opened or closed to make the difference of IR peak intensity of water vapor smaller than a prescribed value between spectra measured by placing and removing the sample in the sample room.

2. The Fourier transform infrared spectrophotometer according to claim 1, wherein the humidifying vessel and the drying vessel are placed outside of the spectrophotometer and attached to the sample room through the first door and the second door, respectively.

3. The Fourier transform infrared spectrophotometer according to claim 1, wherein the humidifying vessel and the drying vessel are arranged inside the sample room.

4. The Fourier transform infrared spectrophotometer of claim 1, wherein the drying vessel is connected to a dry gas source.

5. The Fourier transform infrared spectrophotometer of claim 1, wherein the ambient atmosphere is introduced into the humidifying vessel.

10. The Fourier transform infrared spectrophotometer according to claim 1, wherein a humidity control room which has two optical windows and is connected to the humidifying and drying vessels is added somewhere in the optical path, instead of controlling the humidity of the sample room.

11. The Fourier transform infrared spectrophotometer according to claim 10, wherein the humidifying vessel and the drying vessel are placed outside of the spectrophotometer and attached to the humidity control room through the first and second doors, respectively.

12. The Fourier transform infrared spectrophotometer according to claim 10, wherein the humidifying and drying vessels are respectively arranged inside the humidity control room.

13. The Fourier transform infrared spectrophotometer of claim 10, wherein the drying vessel is connected to a dry gas source.

14. The Fourier transform infrared spectrophotometer of claim 10, wherein the ambient atmosphere is introduced into the humidifying vessel.

6. A Fourier transform infrared spectrophotometer to reduce spectral noises due to carbon dioxide gas, comprising:

a sample room in which a sample is placed,

a vessel containing a carbon dioxide gas supplier, which increases carbon dioxide concentration of the sample room through a first door isolating the vessel and the sample room, and

a vessel containing a carbon dioxide adsorber, which decreases carbon dioxide concentration of the sample room through a second door isolating the vessel and the sample room;

whereby the first door and the second door are opened or closed to make the difference of IR peak intensity of carbon dioxide gas smaller than a prescribed value between spectra measured by placing and removing the sample in the sample room.

7. The Fourier transform infrared spectrophotometer according to claim 6, wherein the carbon dioxide supplying vessel and the carbon dioxide adsorbing vessel are placed outside of the spectrophotometer and attached to the sample room through the first and second doors, respectively.

8. The Fourier transform infrared spectrophotometer according to claim 6, wherein the carbon dioxide supplying and adsorbing vessels are arranged inside the sample room.

9. The Fourier transform infrared spectrophotometer of claim 6, wherein the carbon dioxide supplying vessel is connected to an outer gas source.

15. The Fourier transform infrared spectrophotometer according to claim 6, wherein a CO₂-concentration control room which has two optical windows and is connected to the carbon dioxide supplying and adsorbing vessels is added somewhere in the optical path, instead of controlling the CO₂-concentration of the sample room.

16. The Fourier transform infrared spectrophotometer according to claim 15, wherein the carbon dioxide supplying vessel and the carbon dioxide adsorbing vessel are placed outside of the spectrophotometer and attached to the CO₂-concentration control room through the first and second doors, respectively.

17. The Fourier transform infrared spectrophotometer according to claim 15, wherein the carbon dioxide supplying and adsorbing vessels are arranged inside the CO₂-concentration control room.

18. The Fourier transform infrared spectrophotometer of claim 15, wherein the carbon dioxide supplying vessel is connected to an outer gas source.