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

Abstract

Optical methods based on quantum cascade lasers (QCLs) are becoming popular in many life science applications. We report on two trace gas detection schemes based on continuous wave QCLs for on-line detection of nitric oxide (NO) at the sub-part-per-billion level by volume (ppbv, 1 : 10 −9 ), using wavelength modulation spectroscopy (WMS) and Faraday rotation spectroscopy (FRS) at 1894 cm −1 and 1875.73 cm −1 , respectively. Several technical incremental steps are discussed to further improve the sensitivity of these methods. Examples are included to demonstrate the merits of WMS-based sensor: direct monitoring of NO concentrations in exhaled breath, and from plants under pathogen attack. A simple hand-held breath sampling device that allows single breath collection at various exhalation flows (15, 50, 100 and 300 mL/s, respectively) is developed for off-line measurements and validated in combination with the WMS-based sensor. Additionally, the capability of plants to remove environmental NO is presented.

Breath acetone to monitor life style interventions in field conditions: An exploratory study

“…End‐expiratory breath samples (0.5‐0.8 l) were collected in Mylar bags using a hand‐held breath sampler from every study participant before starting the walk (3.30‐8:00 am, after subjects had breakfast), and at the end of the walk (10:30 am‐5:30 pm) on all four days of the event. Blood samples were collected on EDTA and immediately centrifuged, and plasma was aliquoted and stored at −80°C.…”

Quantum cascade laser-based sensors for the detection of exhaled carbon monoxide

“…A custom-built breath-collection device, as described previously [33], is used for online exhaled breath measurements. Briefly, the design of the device is following the recommendations of the American Thoracic Guidelines for collecting exhaled NO [34].…”

Nitric oxide in plants: an assessment of the current state of knowledge

“…This represents an interaction path length with the NO gas sample of 76 m in a compact design. It allows the detection of NO at and below 1 ppb by volume with a second measuring time (Cristescu et al 2012). Each of these gaseous detection platforms offers the ability to obtain multiple real-time measures of NO production from plants, but there are some important deficiencies.…”