An analytical method has been developed and validated for analyzing 48 volatile organic compounds (VOCs) that were found to be present in substantial quantities in the atmosphere. Air samples were collected by active sampling using Tenax/Carbopack X multisorbent tubes and were evaluated by Thermal Desorption Gas Chromatography Mass Spectrometry (TD-GCMS). Experiments conducted using standards demonstrated excellent repeatability with relative standard deviation (%RSD) values lesser than 10%, good linearity with R 2 values of at least 0.99 for a wide range of concentrations between 0.02 to 500 ng, breakthrough values 5% or lower, tube 10 desorption efficiencies close to 100% and good recoveries between 61% to 120%. Sampling volumes and flow rates were tested and selected by evaluating the performance of the multisorbent tubes. 30 mL/min was selected as the optimal flow rate for different sampling volumes depending on the individual compound's breakthrough value and reproducibility during air sampling. Most of the target analytes exhibited acceptable breakthrough of 5% or less, reproducibility within 20% deviation and method detection limits below 500 ppbv. Criteria established by the United States Environmental Protection Agency (USEPA) for sorbent tube sampling (EPA TO-17) were 15 met for most compounds of interest. 65 solvent-free extraction processes are usually coupled with TD-GCMS. Sorbent tubes are heated to high temperatures to desorb analytes. A flow of inert gas is used to extract and transfer these compounds into a cold trap. 32 The trap preconcentrates and focuses all the compounds from the tube, before inverting the 70 flow of inert gas and heating itself to high temperature. 33 Target compounds are injected into the GC column for further separation and analysis. For canisters, an aliquot of air is preconcentrated into the cold trap directly. 34 The trap desorbs at high temperature and together with a flow of inert gas, injects the VOCs into the 75 GCMS. The main advantage of using TD-GCMS is that the method is highly compatible for a wide range of VOCs of varying polarities. Sorbent tubes are reusable for a long period of time, required for the extraction step. 20

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The preliminary oxidation of graphite to graphite oxide followed by a thermal exfoliation is one of the methods most frequently employed in the preparation of graphene. Such thermally reduced graphene can be widely used for several applications that range from coatings to sensing device fabrication. It is therefore important to investigate in detail the fabrication procedure, the structural features of the resulting graphene, and its potential toxicological effects. Low-molecular-weight and carcinogenic compounds are known to be generated during the thermal reduction/exfoliation of graphite oxide. Such compounds are readsorbed onto the reduced material during the cooling process. We investigate here the composition of the organic compounds that are adsorbed onto the graphene material and show that they can be easily released during the following processing steps even at temperatures as low as 50 °C. Some of the released organic compounds are classified as highly carcinogenic. The results shown here are important not only from a chemical point of view to better understand the composition and properties of the graphene material produced, but also to bring attention to the potential toxicological effects that the synthesis itself or the post-production processes can cause.

Carbon nanotubes (CNTs) possess well‐defined structural and chemical characteristics coupled with a large surface area that makes them ideal as sorbent materials for applications where adsorption processes are required. The adsorption properties of carboxylated derivatives of multiwalled carbon nanotubes (COOH‐MWCNT) and singlewalled carbon nanotubes (COOH‐SWCNT), together with their nonfunctionalized counterparts (MWCNT and SWCNT) for 48 common atmospheric volatile organic compounds (VOCs) were determined using thermal desorption–gas chromatography/mass spectrometry (TD‐GCMS). The CNTs exhibited similar recoveries for many of the VOCs compared to the standard sorbent materials, Carbopack X and Tenax TA. However, VOCs with electron donor–acceptor (EDA) properties such as carbonyls, alkenes, and alcohols exhibited poorer recoveries on all CNTs compared to Carbopack X and Tenax TA. The poor recoveries of VOCs from the CNTs has important implications for the long term use and storage of CNTs, because it demonstrates that they will become progressively more contaminated with common atmospheric VOCs, therefore potentially affecting their surface‐based properties.

A 13-test study was performed to determine whether the overlire air and nominal steam load of a waste-to-energy municipal incinerator could be adjusted to minimize formation of the chlorinated dibenzep-dioxins (CDDs) and dibenzofurans (CDFs). Stack emissions and precipitator fly-ash were analyzed for chlorobenzenes, chlorophenols, and polychlorinated biphenyls in addition to the CDDs/CDFs. The results showed that efficient collection of stacksmitted CDDs/CDFs was obtained, and that a single overnight soxhlet extraction with toluene was sufficient for complete recovery of all extractable CDDs/CDFs in fly-ash.No strong correlations were observed between the incinerator variables studied and the CDD/CDF emissions. Likewise, no strong correlations between the concentrations of CDDs/CDFs in stack emissions and concentrations of precursors were obtained, although some trends were observed. Results suggest that the CDD : CDF ratio and relative CDD/CDF congener distributions may be affected by incinerator conditions. Although a specific set of incinerator conditions to minimize CDD/CDF emissions were not developed, it was found that with efficient incinerator operation these emissions can be held below the Ontario provisional guideline.