Sorbent sampling tubes

In this Applications Guide, Markes International describe how thermal desorption (TD) can be used for key applications in the field of food and drink VOC profiling – covering everything from comparing brands of cheese, to improving the shelf-life of ready-to-eat fresh-cut fruit.

Protect the integrity of your sample by correct choice of cap, capping procedure, storage, transport and tracking.

This application note describes the use of thermal desorption (TD) with gas chromatography (GC) for the quantitation of polycyclic aromatic hydrocarbons (PAHs). Here it is shown how a range of PAHs from naphthalene to benzo[ghi]perylene can be readily captured on to specially-optimized sorbent tubes, and released from them quantitatively. Using this technique, low detection limits are obtained for airborne PAHs with minimal breakthrough and excellent linearity, even when the total sampling volume exceeds 400 L.

Emissions of volatile and semi-volatile organic compounds from car interiors can have an adverse effect on vehicle interior air quality (VIAQ), raising concerns for passenger health and safety. This application note describes methods for assessing VIAQ using thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS) for analysis and quantitation of volatile organic and semi-volatile compounds (VOCs and SVOCs).

This Application Note gives advice on which sorbents to use for pumped or diffusive (passive) tube monitoring of various vapour-phase organics, and suggests optimum criteria for conditioning and storing packed tubes.

This Application Note describes the theory and practice of predicting the uptake rate for a particular analyte–sorbent combination when using diffusive (passive) samplers. This can help analysts to overcome the limitation of having to experimentally determine uptake rates for every analyte–sorbent combination of interest.

This Application Note provides a listing of uptake rates for tube-type axial diffusive samplers, for a range of commonly used sorbents. Values are provided for hydrocarbons, halogenated compounds, esters, glycol ethers, ketones, aldehydes and alcohols, while separate lists are given for a few key compounds for exposure periods typical of workplace (8-hour) and environmental (24-hour to 4-week) monitoring scenarios.

This application note summarizes two important and independent studies aimed at extending the compatible analyte range of tests used to determine chemicals released from materials, and associated indoor air quality measurements. The papers compare the performance of single-bed Tenax® TA tubes to those packed with multiple sorbents, and demonstrate how the latter guarantee improved recovery of very volatile compounds without compromising the recovery or stability of heavier target analytes.

In this poster, thermally desorbed diffusive tubes have been shown to be viable ambient air samplers. Their sampling mechanism is well understood/validated, and TD-GC(MS) analytical methods developed for pumped sorbent tubes can be applied. They offer several advantages over pumped sorbent tubes in terms of simplicity, reduced variability, cost, extended sampling times and minimal water interference