SIFT-MS and FA-MS methods for ambient gas phase analysis: developments and applications in the UK

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Clinical Diagnostics

Background:

• Selected ion flow tube (SIFT) is an established technique for studying gas phase ion-molecule reactions.
• Selected ion flow tube mass spectrometry (SIFT-MS) and flowing afterglow mass spectrometry (FA-MS) are UK-developed analytical methods.
• SIFT-MS is a gas/vapour phase analytical method with unique features for ambient analysis.

Purpose of the Study:

• To describe the origins, developments, and unique features of SIFT-MS as an analytical tool.
• To highlight the growing use of SIFT-MS for analyzing humid air, particularly exhaled breath.
• To indicate its application in non-invasive clinical diagnosis and therapeutic monitoring.

Main Methods:

• Utilizes selected ion flow tube mass spectrometry (SIFT-MS) for on-line, real-time analysis.
• Employs complementary flowing afterglow mass spectrometry (FA-MS) for specific applications.
• Case studies involve detection and quantification of metabolites in exhaled breath.

Main Results:

• SIFT-MS and FA-MS demonstrate potential in detecting biomarkers for disease pathophysiology.
• Specific applications include detecting Pseudomonas aeruginosa in cystic fibrosis patients (SIFT-MS).
• FA-MS was used to measure total body water in chronic kidney disease patients.

Conclusions:

• SIFT-MS is a unique, UK-developed analytical method with broad utility.
• Its application as a non-invasive diagnostic tool in clinical settings is growing.
• Future prospects and developments indicate wider exploitation in research and commerce.