Improved peroxyl radical scavenging TOSC assay to quantify antioxidant capacity using SIFT-MS.

We report a new, fast, sensitive variation of the total oxyradical scavenging capacity (TOSC) assay for measuring the antioxidant capacity of pure compounds, plant extracts and biological fluids using selected ion flow tube mass spectrometry (SIFT-MS). The TOSC assay examines the partial inhibition of ethene formation in the presence of antioxidants that compete with alpha-keto-gamma-methiolbutyric acid (KMBA) for reactive oxygen species. The SIFT-MS-TOSC assay takes 15 s for each ethene analysis and the time interval between consecutive analyses is 20 s.

Pathways for the decay of organic dichloramines and liberation of antimicrobial chloramine gases.

When neutrophils phagocytose bacteria, they generate the cytotoxic agent hypochlorous acid (HOCl). The specific role that HOCl plays in bacterial killing is unclear. In the phagosome, it should react with neutrophil proteins to form protein chloramines and dichloramines.

Interference of chlorofluorocarbon (CFC)-containing inhalers with measurements of volatile compounds using selected ion flow tube mass spectrometry.

Selected ion flow tube mass spectrometry (SIFT-MS) is a sensitive technique capable of measuring volatile compounds (VCs) in complex gas mixtures in real time; it is now being applied to breath analysis. We investigated the effect of inhalers containing chlorofluorocarbons (CFCs) on the detection and measurement of haloamines in human breath. SIFT-MS mass scans (MS) and selected ion monitoring (SIM) scans were performed on three healthy non-smoking volunteers before and after inhalation of the following medications: Combiventtrade mark metered-dose inhaler (MDI) (CFC-containing); Ventolintrade mark MDI (CFC-free); Atroventtrade mark MDI (CFC-free), Beclazonetrade mark MDI (CFC-containing); Duolintrade mark nebuliser.

Detection of monobromamine, monochloramine and dichloramine using selected ion flow tube mass spectrometry and their relevance as breath markers.

We report a fast, sensitive, real-time method to measure monobromamine, monochloramine and dichloramine using selected ion flow tube mass spectrometry (SIFT-MS). Relative rate coefficients and product distributions are reported for the reagent ions H3O+ and O2 +. Rapid reactions with the haloamines were observed with H3O+ and O2 + but no fast reaction was found with NO+.

Classifying algorithms for SIFT-MS technology and medical diagnosis.

Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS) is an analytical technique for real-time quantification of trace gases in air or breath samples. SIFT-MS system thus offers unique potential for early, rapid detection of disease states. Identification of volatile organic compound (VOC) masses that contribute strongly towards a successful classification clearly highlights potential new biomarkers.

Classification algorithms for SIFT-MS medical diagnosis.

Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS) is an analytical technique for the real-time quantification of trace gases in air or breath samples. The SIFT-MS system can potentially offer unique capability in the early and rapid detection of a wide variety of diseases, infectious bacteria and patient conditions, by using a classifier to differentiate between control and test groups. By identifying which masses and Volatile Organic Compounds (VOCs) contribute most strongly towards a successful classification, biomarkers for a particular disease state may be discovered.

Composition of volatile organic compounds in diathermy plume as detected by selected ion flow tube mass spectrometry.

Background: There is some evidence that surgical plume may pose a risk to health professionals, but the risks posed by volatile organic compounds have not been thoroughly investigated.

Methods: The composition of volatile organic compounds in diathermy plume produced during surgery was analysed by selected ion flow tube mass spectrometry.

Results: Hydrogen cyanide (3-51 parts per million), acetylene (2-8 parts per million), and 1,3-butadiene (0.

Major volatile compounds in head-space above olive oil analysed by selected ion flow tube mass spectrometry.

Selected ion flow tube mass spectrometry (SIFT-MS) is a technique that is well suited to the real-time analysis of head-space. SIFT-MS gives a non-discriminatory snapshot of the volatiles present and their amounts, and is considered to display less bias than chromatographic techniques as neither sample pre-treatment nor separation are necessary in most cases. The technique has been used for analysis of virgin olive oil head-space on more than 100 different oils.

Real time analysis of breath volatiles using SIFT-MS in cigarette smoking.

The selected ion flow tube mass spectrometry (SIFT-MS) technique enables real time analysis of trace volatiles at ppb levels without preconcentration steps or chemical derivatization. Most previous studies of trace compounds on the breath were analyzed using gas chromatography where enhanced detection sensitivity was achieved by concentrating the breath using cryogenic or adsorption trapping techniques. In this paper, we have examined volatile organic substances, isoprene, acetone, ammonia and ethanol in breath before and after smoking a cigarette.

Quantitative analysis of trace gases of breath during exercise using the new SIFT-MS technique.

We show how the concentration of the breath gases ammonia, acetone, and isoprene vary with time during exercise using the new selected ion flow tube mass spectrometry (SIFT-MS) technique. The expired breath concentrations of ammonia, acetone and isoprene were observed within the range of 50-500, 100-1400 and 5-400 ppb, respectively. Increasing acetone levels were observed for most subjects during the exercise period.