Environmental monitoring

The impact of COVID-19 lockdowns on New York City's air quality: continuous, cryogen-free on-line monitoring of PAMS in ambient air using hydrogen carrier gas 

This study demonstrates the advantages of using Markes’ Multi-Gas thermal desorption (TD) with gas chromatography (GC) and hydrogen carrier gas for the analysis of ozone precursors in air. Also presented is a case study and some new findings possible thanks to the reduced traffic pollution during lockdown periods. 

Analysis of trace per- and polyfluorinated organic vapours in air using cryogen-free thermal desorption and GC-MS

This study describes the sampling and analysis of a challenging range of trace-level volatile and semi-volatile vapours of per- and polyfluorinated alkyl substances (PFAS) in air. The analytical system used combines modern single-quadrupole GC-MS technology and a TD100-xr™ automated thermal desorption (TD) system from Markes International, which operates without a liquid cryogen coolant and complies fully with relevant international standard methods. Excellent method performance (linearity, repeatability, storage stability, etc.) was demonstrated across the range of compounds tested, including low or sub-ppt detection limits for all compounds. 

Untargeted screening of volatile PFAS released during the application of aqueous film-forming foam (AFFF)

This study describes how thermal desorption with gas chromatography-mass spectrometry (TD-GC-MS) can be used to monitor the release of per- and polyfluoroalkyl substances (PFAS) during the application of aqueous film-forming foam (AFFF). The results of the study show that TD-GC-MS can be used to analyse target compounds and screen for non-target compounds, enabling researchers to gain a greater understanding of AFFF emissions.