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The method includes sensitizing in a first ray path to the isotope component and sensitizing in a second ray path to the isotope-pure measuring gas, and electronically amplifying the measurement results.
In order to improve the selectively and the sensitivity while maintaining a simple construction, an additional optical filtering is carried out in the first ray path by a filter filled essentially with isotope-pure measuring gas and the electronic measuring value of the second ray path is entered by influencing the amplification factor and an offset in the electronic amplification of the first ray path.
Description This is a continuation of application Ser.
|Fundamental Principles of X-Ray Fluorescence (XRF)||It works on wavelength-dispersive spectroscopic principles that are similar to an electron microprobe EPMA. However, an XRF cannot generally make analyses at the small spot sizes typical of EPMA work micronsso it is typically used for bulk analyses of larger fractions of geological materials.|
|You are here||Statistic result of the five tested wavelengths.|
|Fourier Transform Infrared Spectroscopy (FTIR) Analysis||In the present study a novel approach for Fourier transform infrared FT- anti-carcinogenic properties.|
Field of the Invention The present invention relates to a method and an apparatus for the selective determination of an isotope portion of a measuring gas by means of non-dispersive infrared spectroscopy. Description of the Related Art The selective determination of isotope portions has gained particular importance in the fields of biology, geology and archeology, and in recent times even in the field of medicine.
The so-called 13 C-Method, which Infrared spectrometer and sampling techniques been established for a long time in the fields of geology and archeology, is utilized as a method for the determination of the age of dead matter.
In addition, stable isotopes have been used for considerable time as marking in order to be able to examine metabolic processes in living matter, for example, in the field of medicine.
When using isotopes in the fields of medicine or biology, i. In many cases, they are the nitrogen isotope 15 N or the carbon isotope 13 C. This energy changes the metabolic processes or breaks up chemical bonds.
In the field of medicine, the use of radioactive isotopes is generally prohibited. The use of 13 C has become popular as a marking element for the diagnostic evaluation of metabolic diseases or diseases of the gastrointestinal system in humans.
Particularly successful is the use of 13 C as a marking element for the diagnostic evaluation of infectious stomach diseases, such as, helicopacter pylory infections. These infections can be diagnosed simply after a dose of 13 C-marked urea through the expiration air of patients.
This makes a complicated gastroscopy superfluous. In the above-described applications as well as in other applications, mass spectrometric methods are used because of the requirements made of the selectivity of the measuring method. Because of the necessity to produce a high vacuum and because of the complicated sample preparation as well as the technically complicated design of the analyzer, these methods are expensive and, thus, are difficult to realize in many laboratories.
It is also known in the art to use a purely optical method, i. Such a possibility has already been described in Chemical Abstracts, Vol.
The use and the conditioning of non-dispersive infrared spectroscopy is also known from U. These known apparatus and methods have the disadvantage that the selectivity or the sensitivity of the infrared spectrometer does not always make possible a secure measurement or a secure diagnosis.
In accordance with the present invention, an additional optical filtering is carried out in the first ray path by a filter filled essentially with isotope-pure measuring gas and the electronic measuring value of the second ray path is entered by influencing the amplification factor and an offset in the electronic amplification of the first ray path.
The apparatus according to the present invention includes a non-dispersive infrared spectrometer with a first and a second ray path each composed of an infrared radiator, a measuring vessel and a detector, with amplification detectors which produce at the output an electric output signal.
For the selective determination of the isotope portion of a measuring gas, a filter vessel filled with gas primarily corresponding to the isotope-pure measuring gas is arranged between the measuring vessel and the detector of the first ray path.
The subsequent detector is sensitized to the isotope which is proportionately to be determined. The detector of the second ray path is sensitized to the isotope-pure measuring gas. Accordingly, the present invention utilizes the known configuration of a non-dispersive infrared spectrometer and supplements it with appropriate elements.
One of the fundamental problems which must be overcome when increasing the sensitivity of a non-dispersive infrared spectrometer for the determination of isotope concentrations is the high transverse sensitivity of the marked gas and of the unmarked gas.
This is caused by the great overlap of the infrared spectra which overlap, in turn, results from the low mass difference between the gases.
An additional effect which poses a problem in this connection is the carrier gas dependency. These effects are significantly reduced by the combination according to the present invention of an optical filtering with a subsequent electronic influencing of the signal.
However, the description is also applicable to other gases. The optical filter is composed of an additionally arranged filter which is filled with 12 CO2 and is arranged in the first ray path in which the 13 CO2 detector is arranged. The 12 CO2 concentration is measured in the second ray path.
The measurement range is approximately times greater than the 13 CO2 measuring range, so that transverse sensitivities of 13 CO2 are negligible in the second ray path.
For correcting the remaining transverse sensitivity of the 13 CO2 duct, the electric output signal of this duct is computed with that of the 13 CO2 duct, in the manner described in the above summary of the method of the present invention.
This means that there remains the influence of 12 CO2 on the 13 CO2 duct of below 1 ppm. Because of aging phenomena in the measuring system and in new installations after transportation, there is the question of calibration by means of appropriate test gases.
This calibration is carried out in accordance with the present invention by means of calibration vessels filled with the components 13 CO2 and 12 CO2. Room air which is freed of CO2 is additionally added.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure.
For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described a preferred embodiment of the invention.
The upper curve represents the output signal pattern a without the inventive measures, i. The pattern b results from a pure offset shift which is caused by the additional filter vessel which is filled with 12 CO2 and is placed in the measuring ray path of the 13 CO2 duct.
Consequently, the pattern b is transferred to the pattern c.I-Infrared spectrometer and sampling techniques Spectrophotometer Spectrophotometry in chemistry is a quantitative measure of the reflection or transmission of material properties as .
Comparison of Three Fourier Transform Infrared Spectroscopy Sampling Techniques for Distinction sampling techniques leads to the question of how researchers choose which mode of FTIR to use.
spectrometer (Spectrum 2; Perkin Elmer, Waltham, MA) using DRIFTS, ATR, and. 1. Scope. This field test method employs an extractive sampling system to direct stationary source effluent to an FTIR spectrometer for the identification and quantification of gaseous compounds.
Karl H. Norris. Karl Norris is regarded as the “father” of modern near infrared spectroscopic analysis. He invented the technique while working at the USDA Instrumentation Research Laboratory, Beltsville, USA.
Title: Rapid Analysis of Trans Fat Content Using a Fourier Transform Infrared Spectrometer Subject: Application Note Food manufacturers can use the infrared ATR technique for rapid determination of the trans fat content of the fats and oils used in the manufacture of food products.
The general absorbance levels of the spectra of both sampling main way to validate the information of each calibration techniques are expected to depend on the total solids contents equation is the interpretation of the main spectral features (i.e., contents of fat, carbohydrates, proteins, etc.), the scaling responsible for modeling, as.