Garbage in, garbage out – the vital role of inert coatings in volatile chemical measurement with thermal desorption.

It is easy to overlook sample introduction in complex analytical workflows, but the quality of any result is only as good as the sample itself. Inert coatings are vital in protecting sample integrity during sampling and sample introduction for gas chromatography (GC). Thermal desorption (TD) is a versatile sampling and pre-concentration technique for GC best known for its widespread application in environmental air analysis. TD provides solvent, cryogen and now helium-free sample concentration and introduction options for volatile and semi-volatile organic compounds. TD has evolved far beyond air analysis and here we discuss the importance of inert surfaces for some of the most demanding applications of TD. TD is relied upon to keep military personnel and civilians safe during recovery and destruction of chemical warfare munitions and in routine monitoring for threat of chemical attack. Measurement of airborne chemical warfare agents requires sampling and analytical techniques that deliver robust and reliable transfer of highly reactive compounds at ultra-trace concentration levels. Inertness is critical at every stage of the workflow. Hydrogen is emerging as front runner in the drive for clean energy solutions yet widespread adoption is hampered by the negative impact of impurities at even ppt levels. This case study will show how TD can provide on-line and off-line measurement for highly reactive volatile impurities including hydrogen sulfide and formaldehyde. In our third case study we will explore early disease diagnosis using volatile compounds collected from exhaled breath. As this exciting research area grows at pace maintaining sample integrity throughout sampling, long term storage and analysis of irreplaceable samples relies upon stringent quality control. In this case study we will show how inert coated thermal desorption tubes preserve even notoriously unstable compounds like mercaptans and terpenes enabling long term storage and batch analysis.