Ultrasensitive laser spectroscopy for breath analysis

Abstract

At present there are many reasons for seeking new methods and technologies that aim to develop new and more perfect sensors for different chemical compounds. However, the main reasons are safety ensuring and health care. In the paper, recent advances in the human breath analysis by the use of different techniques are presented. We have selected non-invasive ones ensuring detection of pathogenic changes at a molecular level. The presence of certain molecules in the human breath is used as an indicator of a specific disease. Thus, the analysis of the human breath is very useful for health monitoring. We have shown some examples of diseases’ biomarkers and various methods capable of detecting them. Described methods have been divided into non-optical and optical methods. The former ones are the following: gas chromatography, flame ionization detection, mass spectrometry, ion mobility spectrometry, proton transfer reaction mass spectrometry, selected ion flow tube mass spectrometry. In recent twenty years, the optical methods have become more popular, especially the laser techniques. They have a great potential for detection and monitoring of the components in the gas phase. These methods are characterized by high sensitivity and good selectivity. The spectroscopic sensors provide the opportunity to detect specific gases and to measure their concentration either in a sampling place or a remote one. Multipass spectroscopy, cavity ring-down spectroscopy, and photo-acoustic spectroscopy were characterised in the paper as well.

Clinical Application of Volatile Organic Compound Analysis for Detecting Infectious Diseases

“…The introduction of new analytical approaches and technological developments in instrumentation has enabled the detection of low concentrations of VOCs in clinical samples such as exhaled breath, urine, and feces of patients and has allowed us to predict those which are found to be distinctive (based on qualitative and/or quantitative variations) compared to healthy individuals or are linked to a disease state (27)(28)(29)(30)(31)(32).…”

Utmost response time of long-wave HgCdTe photodetectors operating under zero voltage condition

“…Applications requiring frequencies [ 1 GHz and operating under zero voltage and room temperatures contribute to the development of the new device architectures (Piotrowski and Rogalski 2007;Rogalski 2011;Wojtas et al 2012). That trend is also visible in the long-wave (8-12 lm, LWIR) range HgCdTe detectors.…”

Nitrogen Oxides Optoelectronic Sensors Operating in Infrared Range of Wavelengths

“…In medicine nitrous oxide (N 2 O) is used as an anaesthetic, especially in dentistry and minor surgery. Its excess in air lead to mild hysteria and a laughter [3]. Thus it is also known as laughing gas.…”