DIODE-LASER BASED PHOTO-ACOUSTIC SPECTROSCOPY IN ATMOSPHERIC NO­2 DETECTION

We have developed a simple, low cost, and compact NO2 detection system. It’s based on photoacoustic spectroscopy (PAS) method uses a diode laser as a source of radiation. The PAS system has a detection limit of 10 ppbv for NO2. With this set-up we were able to detect the NO2 concentration from urban air near our campus. We have also investigated the NO2 dissociation effect on the PAS system via NO measurements using a direct absorption spectroscopy method on quantum cascade laser (QCL) system. Keywords: photoacoustic spectroscop

Spectroscopic Detection of Trace Gases in Medical Sciences

Item does not contain fulltextRU, Molecular and Laser Physics, 28 november 2006Promotor : Parker, D.H. Co-promotores : Harren, F.J.M., Cristescu, S.M.128 p

Pharmacokinetics of ethylene in man by on-line laser photoacoustic detection

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Quantum cascade laser-based carbon monoxide detection on a second time scale from human breath

Contains fulltext : 35493.pdf (publisher's version ) (Closed access)We present three different detection schemes for measuring carbon monoxide (CO) in direct absorption using a thermoelectrically cooled, distributed-feedback pulsed quantum cascade (qc) laser operating between 2176 and 2183 cm(-1). The laser emission has overlap with the strong R(8)1 rovibrational transition in CO at 2176.2835 cm(-1). Firstly, by utilizing the frequency chirp of the qc-laser with long laser pulses, a minimal detectable absorption of 1.2 x 10(-5) cm(-1) is achieved at an acquisition rate of 3 Hz. Additionally, with short laser pulses and slow frequency scanning a minimal detectable absorption 8.2 x 10(-7) cm(-1) is reported, with an acquisition time of 60 s. Finally, a novel amplitude modulation technique is developed to facilitate real-time measurement of CO in exhaled air. The application of this detector to detection of CO in a single breath as a potential non-invasive diagnostic tool is shown

Real-time trace gas sensing of ethylene, propanal and acetaldehyde from human skin in vivo.

Contains fulltext : 35507.pdf (publisher's version ) (Closed access)Trace gases emitted by human skin in vivo are monitored non-invasively and in real time using laser-based photoacoustic detection and proton-transfer reaction mass spectrometry. A small quartz cuvette is placed on the skin to create a headspace from which a carrier gas transports the skin emissions to the detection systems. The transparency of quartz to ultraviolet radiation (UVR) allows investigation of UVR-related trace gas emissions. As a demonstration of this measurement system, the effect of supplemental intake of systemic antioxidants on UVR-induced lipid peroxidation is investigated. The production by the skin of three biomarkers of UVR-induced lipid peroxidation (ethylene, acetaldehyde and propanal) is monitored. Although no significant effect of antioxidant intake was observed, the method presented here is a novel and promising technique for investigation of human skin in vivo

On-line monitoring of UV-induced lipid peroxidation products from human skin in vivo using proton-transfer reaction mass spectrometry.

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Fourier transform and high sensitivity cw-cavity ringdown absorption spectroscopies of ozone in the in the 6030-6130 cm –1 region. First observation and analysis of the 3v1 + 3v3 and 2v2 + 5v3 bands

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Laser-based systems for trace gas detection in life sciences

Contains fulltext : 72094.pdf (publisher's version ) (Closed access)7 p

Spectroscopic monitoring of NO traces in plants and human breath: applications and perspectives

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