An analyzer aimed for single-breath detection of exhaled endogenous NO is described. It is based on lead-salt MBE tunable diode lasers (TDL) operating at 5.4 im spectral region. Specially designed high sensitive and fast acquisition system used in combination with the Herriott multipass gas cell allows 1 ppb concentration sensitivity to exhaled NO with about 0.5 5 temporal resolution. Careful selection of the used analytical spectral region ensures high NO detection selectivity in the condition of elevated water vapor and carbon dioxide content in exhaled air. Due to the TDL high spectral resolution the analyzer is also insensitive to the other numerous endogenous substances that could be present in exhaled air. The TDL NO analyzer was tested in measuring endogenous NO content in exhalation of patients suffering from different pulmonary diseases as well as of healthy control subjects. Some single-breath NO trace specific in asthma and COPD was observed allowing differentiation of these diseases with the exhalation NO test.Keywords: Biomedical diagnostics with tunable diode lasers, gas analysis of exhalation content, endogenous NO in exhaled air, NO excretion in asthma and COPD.
A family of multicomponent gas analyzers based on tunable diode lasers (TDL) are presented including: an open optical path 3-component gas analyzer for monitoring atmosphere pollution; a 4-gas component analyzer with a multipass cell, a multichannel TDL system with multipass cell and ]VIIR fiber optics delivery, and a multichannel TDL analyzer for breath content gs analysis. A4B6 tunable diode lasers of different spectral region from 4 to 12 micron were used in every channel of the analyzers to obtain atmospheric transmission spectra and to measure concentration of studied gases. Main gaseous atmospheric pollutants like CO. NO, NH3, CH, SO2, etc. and some of breath gases could be measured at ppb concentration level in real time with these systems depending on customers requirements. The analyzers are driven by IBM compatible PC. The first results on field monitoring tests as well as on their application to human exhalation content analysis and human exposure monitoring are presented.
1JNTRODUCTLONWithin the framework of this studies development of a model of a functional multicomponent highly sensitive new generation analyzer, designed to measure 2 to 4 gas components in a mixture, was proposed. This model will become a prototype for a whole new family of analyzers, which will differ from one another by their particular set of detected gases and sensitivity depending on task requirements.
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