Applying the diode laser spectroscopy method for high sensitivity on-line control of¹³С contained in the gaseous mixture with¹²С

Abstract

This letter details the development of an on-line control method for carbon dioxide molecules of various isotopes contained in gaseous media on the basis of a tunable diode laser operating in the 4860–4880 cm−1 range. It shows that the sensitivity of 13С registering may amount to ~1012 cm−3.

Application of adaptive filters to improve online detection sensitivity of 13CO2 in a mixture with 12CO2 in expiratory air

“…Thus, using such an approach to measure the absorption of rotational lines P(18) of the 13 CO 2 molecule and R (24), R (26) of the 12 CO 2 molecule have been reported previously [4]. The accuracy of measuring the concentration ratios of 13 CO 2 and 12 CO 2 obtained in this work is 2% with a concentration ratio of [ 12 CO 2 ]/[ 13 CO 2 ] ~ 140, the sensitivity of measuring 13 CO 2 is 3.7 • 10 15 cm −3 , and the minimum detectable fraction of 13 CO 2 in a mixture with the 12 CO 2 is 1.4 • 10 −5 .…”

“…A comparison with the results of [4], in which the fast Fourier transform filter (FFT filter) has been used to process the experimental signal, has shown clearly that the application of adaptive Kalman, Wiener and EMD filters can improve the measuring sensitivities of the 13 CO 2 content in expiratory air by about four times. At the same time, the minimum detectable fraction of 13 CO 2 in a mixture with 12 CO 2 is also reduced by about four times.…”

“…It is known that an effective tool for the noninvasive diagnosis ofgastrointestinal tract (GIT) oncology diseases is the use of respiratory tests to measure the 13 C isotope content in expiratory air, which is part of the 13 CO 2 molecule [1,2]. The problem of highly sensitive and highly accurate online measurement of 13 CO 2 in a mixture with the 12 CO 2 in human expiratory air, as shown by the analysis, can be solved by implementing the tunable diode laser absorption spectroscopy (TDLAS) technique using tunable diode lasers (TDL) emitting near the wavelength of 2 µm [1][2][3][4][5][6][7][8][9].…”

The H2S online detection in gaseous media using diode laser absorption spectroscopy in the range of 4860–4880 cm−1

“…One of the promising high-sensitive H 2 S detection methods may become the tunable diode laser absorption spectroscopy (TDLAS) based on the phenomenon of direct absorption of laser radiation by gas, previously implemented for some other substances, for instance, 13 CO 2 [20][21][22][23][24][25][26][27][28]. This method is characterized by high selective ability, making it possible to resolve vibrational-rotational absorption spectra of various substances mixed together.…”

Use of pump current modulation of diode laser for increased sensitivity of detection of13СO2in human exhaled breath

“…Detecting the content of 13 СО 2 in a mixture with 12 СО 2 in the expired air requires high measuring speed with time peri ods at the level of 0.1 s. Besides that, the required sensitivity for detecting 13 СО 2 is at the level of 0.1-1 ppm, and measure ment accuracy is at the level of 3%-5% [1]. An analysis of the results to date shows that to solve this problem, optical absorption methods, which provide high sensitivity, measure ment accuracy, and the ability to obtain results in the online mode, are among the most promising [4][5][6][7]. Some of the best results were achieved using frequencytunable diode lasers (TDLs) operating in the infrared spectral range close to 4.3, 2 and 1.6 µm wavelengths as radiation sources [8].…”