Comparative study of the adsorption performance of a multi-sorbent bed (Carbotrap, Carbopack X, Carboxen 569) and a Tenax TA adsorbent tube for the analysis of volatile organic compounds (VOCs)

Abstract

A comparison between two types of adsorbent tubes, the commonly used Tenax TA and a multi-sorbent bed (Carbotrap, Carbopack X, Carboxen 569) tube developed in our laboratory, has been done to evaluate their usefulness in the analysis of VOCs in ambient air. Duplicate indoor and outdoor samples of Tenax TA and multi-sorbent tubes of 10, 20, 40, 60 and 90l were taken in Barcelona city (Spain) on July and October of 2009. Breakthrough values (defined as %VOCs found in the back tube) were determined for all sampling volumes connecting two sampling tubes in series. The analysis was performed by automatic thermal desorption (ATD) coupled with capillary gas chromatography (GC)/mass spectrometry detector (MSD). Significant differences between the concentrations obtained-from multi-sorbent bed and Tenax TA tubes are observed for the very volatile compounds (56 degrees C<boiling point<100 degrees C and 4kPa<vapour pressure (20 degrees C)<47kPa) (e.g. acetone, isopropanol, n-hexane) and for alcohols and chlorinated compounds (e.g. 1-butanol, carbon disulphide, dichloromethane, chloroform, carbon tetrachloride, trichloroethylene, tetrachloroethylene), being the concentrations found higher in multi-sorbent bed than in Tenax TA tubes. On the other hand, mainly all compounds with boiling points higher than 100 degrees C (except alpha-pinene, chlorinated and polar compounds) do not show significant differences between the obtained multi-sorbent bed and Tenax TA tube concentrations. For the concentrations obtained (5ppt to 100ppb), Tenax TA present high breakthrough values (from 0 to 77%) for mainly all compounds and sampling volumes studied. On the other hand, multi-sorbent bed tubes do not exhibit important breakthrough values for these compounds, except the VVOCs ethanol (for all sampled volumes), and acetone, dichloromethane and isopropanol (for sampling volumes over 40l). The concentration differences observed between Tenax TA and multi-sorbent bed tubes are directly related to the high breakthrough values determined for Tenax TA adsorbent.

Volatile Organic Compounds in Ambient Air at Four Residential Locations in Seoul, Korea

“…The performance and reliability has been tested commonly for this type of multibed samplers with similar sorbent compositions. For instance, Gallego et al (2010) investigated relative performance between three sorbent bed tube samplers and a single bed tube (Tenax TA). These authors observed significant differences in measured data between the two tubes from the very volatile compounds (56°C < boiling point [bp] < 100°C and 4 kPa < vapor pressure (20°C) < 47 kPa; e.g., acetone, isopropanol, n-hexane) and alcohols and chlorinated compounds (e.g., 1-butanol, carbon disulphide, dichloromethane, chloroform, carbon tetrachloride, trichloroethylene, and tetrachloroethylene).…”

Removal of chlorinated organic volatile compounds by gas phase adsorption with activated carbon

“…Adsorption, absorption and condensation are the three most common non-destructive techniques for the removal/recovery of Cl-VOCs from gas streams [21][22][23][24]. Adsorption with activated carbon (AC) has been widely used for the removal of gaseous organic pollutants [25,26].…”

Proton Transfer Reaction Mass Spectrometry: Applications in the Life Sciences

“…Regarding breakthrough volumes, studies using a combination of Carbotrap, Carbopack X and Carboxen-569 showed breakthrough volumes lower than 5% for a wide range of VOCs, including benzene, toluene, xylene and alpha-pinene; for acetone, breakthrough volumes were found to be dependent on the volume sampled ( [197]; [199]). Experiments using a mixture of Carbograph 2 and Carbograph 5 also showed low breakthrough volumes (<1%) for a number of VOCs, including o-xylene [201].…”

“…However, it is not always possible to bring the source of volatiles and the analytical device together. To circumvent this problem, volatile storage containers can be used such as Teflon or Tedlar bags ( [191]; [192]; [193]), canisters ( [194]; [195]), and Tenax TA or Carbotrap/Carbograph thermodesorption tubes ( [196]; [197]; [198]; [199]). Thermo desorption tubes trap different groups of volatiles depending on the sorbent placed inside the tubes, either by diffusion or by pumping the gas through the tube.…”