High-resolution cavity leak-out absorption spectroscopy in the 10-μm region

Mürtz, Manfred; Frech, B.; Urban, W.

doi:10.1007/s003400050613

Cited by 50 publications

(24 citation statements)

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“…This information can then be used to calculate the decay rate. The decay rate indicates the amount of photons lost, which in turn, defines the species of gases in the cavity [73]. The following equation shows how the decay rate ( -1 ) decreases according to the rate at which the breath sample absorbs light:…”

Section: Laser Spectroscopymentioning

confidence: 99%

Breath Ammonia Analysis: Clinical Application and Measurement

Hibbard

Killard

2011

Critical Reviews in Analytical Chemistry

119

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Section: Laser Spectroscopymentioning

confidence: 99%

Breath Ammonia Analysis: Clinical Application and Measurement

Hibbard

Killard

2011

Critical Reviews in Analytical Chemistry

119

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“…Further emphasis should be directed in the development of small, easy-to-handle, portable devices for the investigation of the exhaled gas profi les (such as VOCs) and their role especially in COPD. Real time analysis of volatile organic molecules by infrared laser spectroscopy enables online measurement of oxidative markers (Murtz et al 1999) and these techniques offer the potential for real time monitoring of EBC also in asthma and COPD. Metabolomic analysis (quantitative measurement of the dynamic multiparametric metabolic response of living systems to pathophysiological stimuli or genetic modifi cation) (Nicholson et al 1999) can provide new biochemical profi les for the assessment of low molecular weight metabolites in EBC.…”

Section: Perspective/conclusionmentioning

confidence: 99%

Airway biomarkers of the oxidant burden in asthma and chronic obstructive pulmonary disease: Current and future perspectives

Louhelainen

Myllärniemi²,

Rahman³

et al. 2008

COPD

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Abstract:The pathogenesis of asthma and chronic obstructive pulmonary disease (COPD) has been claimed to be attributable to increased systemic and local oxidative stress. Detection of the oxidant burden and evaluation of their progression and phenotypes by oxidant biomarkers have proved challenging and diffi cult. A large number of asthmatics are cigarette smokers and smoke itself contains oxidants complicating further the use of oxidant biomarkers. One of the most widely used oxidant markers in asthma is exhaled nitric oxide (NO), which plays an important role in the pathogenesis of asthma and disease monitoring. Another oxidant marker that has been widely investigated in COPD is 8-isoprostane, but it is probably not capable of differentiating asthma from COPD, or even sensitive in the early assessment of these diseases. None of the current biomarkers have been shown to be better than exhaled NO in asthma. There is a need to identify new biomarkers for obstructive airway diseases, especially their differential diagnosis. A comprehensive evaluation of oxidant markers and their combinations will be presented in this review. In brief, it seems that additional analyses utilizing powerful tools such as genomics, metabolomics, lipidomics, and proteomics will be required to improve the specifi city and sensitivity of the next generation of biomarkers. Keywords: sputum, condensate, smoking, nitric oxide, 8-isoprostane, biomarker Asthma and chronic obstructive pulmonary disease (COPD) are diseases with different physiological and anatomical features. However, a signifi cant number of patients suffering from these diseases exhibit symptoms and signs which are associated with both conditions. Markers of the elevated oxidant burden have been detected in both of these disorders. This degree of overlap between asthma and COPD has proved to be especially important in smoking asthmatics, patients who have often been excluded from asthma trials and investigations. Oxidant markers are under intensive investigation as ways of assuring the early detection and monitoring of asthma and COPD, for the differentiation of the disease from the condition of "healthy smokers", and also for the evaluation of the COPD phenotypes and their progression. This review will critically review potential markers that refl ect oxidative stress in the airways of patients with asthma and COPD in exhaled air, exhaled breath condensate (EBC) and induced sputum. In addition, markers in bronchoalveolar lavage (BAL) will also be briefl y surveyed, even though the technique, ie, fi breoptic bronchoscopy is an invasive technique used in the investigation of lung infl ammation and the evaluation of the oxidant burden. In this review, we will also discuss the pros and cons of various noninvasive biological samples for assessing the oxidant burden in the airways, and then speculate on the possibilities of using the existing and new oxidant markers,

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“…After excitation, the laser power is turned off and the subsequent decay of the radiation stored in the cavity is observed via detection of the light leaking out through one of the cavity mirrors. Measurement of the decay time is used to determine the photon losses and thus to detect weakly absorbing species inside the cavity [31]. D. Halmer et al observed a noise-equivalent absorption coefficient of 7·10 −11 cm −1 Hz −1/2 using a cavity of 0.5 m length with R > 0.9999 mirrors.…”

Section: Fig 2 Typical Setup Of Mupass Systemmentioning

confidence: 99%

Application of quantum cascade lasers to trace gas detection

Bielecki¹,

Stacewicz²,

Wojtas³

et al. 2015

Bulletin of the Polish Academy of Sciences Technical Sciences

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Abstract. The potential of Quantum Cascade Laser technology has been recently harnessed in industry, medicine and military to create a range of original infrared gas sensors. These sensors have opened up many new applications due to compact size, excellent sensitivity, robust construction and low power requirements. They rely on infrared absorption spectroscopy to determine identity and quantity of gases. The measurement of these gases has relied on different technologies including multi-pass spectroscopy, photoacoustic spectroscopy, cavity ring down spectroscopy, and their various modifications. In this review paper some technologies are described in terms of its advantages/disadvantages in many application. The results of own works about methane, ammonia, nitric oxide, nitrous oxide, and carbonyl sulfide detection are presented as well.

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High-resolution cavity leak-out absorption spectroscopy in the 10-μm region

Cited by 50 publications

References 0 publications

Breath Ammonia Analysis: Clinical Application and Measurement

Breath Ammonia Analysis: Clinical Application and Measurement

Airway biomarkers of the oxidant burden in asthma and chronic obstructive pulmonary disease: Current and future perspectives

Application of quantum cascade lasers to trace gas detection

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