Exposure to various groups of SVOCs, particularly in the indoor air, is of increasing concern worldwide. These groups include PAHs, PCBs, phthalate esters, organochlorines, and many others, which are classified among the priority organic pollutants. A new method was developed and optimized for simultaneous whole air sampling using recent canister/helium diffusion technology followed by online cryogenic trapping, concentration of the SVOCs, and direct on-column injection into the GC/MS. The method was optimized using 25 SVOCs (seven of PAHs, eight of PCBs, four of phthalates, three OCs, and three of others) and tested in the analysis of 294 air samples, which were collected from the outdoor and the indoor at eight large office buildings on 21 different dates from January 2011 to August 2011. The method detection limits ranged from 0.05 ppbv for 2,4-dinitrobenzene to 2.6 ppbv for chrysene. Phthalates were the most abundant among other SVOCs, whereas fluorine and dichlorobiphenyl were the most abundant among the PAHs and PCBs, respectively. The I/O ratios of most SVOCs were < 1, indicating that the outdoor air was the main source of indoor pollutants. The method demonstrated: (1) accurate and efficient for various SVOCs determination, which allowed assessment of the factors affecting their levels in the sampling locations, and (2) the capability of reliable use of recent technology which eliminates the disadvantages of using sorbents and solvents by the current methods.
Link to Springer
The Entech 7650-L20 is the only system handling automated injection of Tedlar bags and other gas phase samples using a single inlet robotic autosampler. The 7650-L20 can automate the analysis of up to 16 Tedlar bags, or 24 to 80 Bottle-Vac samplers or MiniCans depending on the size of the canister or Bottles. Canisters and gas sampling Bottle-Vacs can be heated prior to analysis to extend the molecular weight range of recoverable compounds, allowing a reliable way of measuring heavy volatiles or semi-volatiles. The dual loop system simultaneously injects an Internal standard along with the sample or calibration standard to support internal standard calibration methods. A 100% Silonite coated ceramic pathway ensures recovery of difficult compounds, creating the most comprehensive technique available for the quantitative measurement of organic compounds in gas phase samples. The 7650-L20 can automate the injection of gas samples to virtually all GCs by using the model specific communication cables available from Entech.
A new, simplified approach for filling air sampling canisters during monitoring of Environmental pollutants in air is described. The new approach uses helium diffusion to drive the sampling process in a way that has several advantages over vacuum sampling. Canisters are filled with helium after cleaning, using a valve and inlet fitting combination that allows the proper time integrated sample to be collected simply by removing the valve and allowing helium to leak out through a calibrated orifice. Orifice sizes are available for performing a range of integration times from 3 hours to 1 month, without the need for an external flow controller. Elimination of the flow controller from the flow path reduces sample loss, prevents contamination from previous sampling events, greatly increases simplicity and reliability of the sampling process, and increases the molecular weight range recoverable to include Semi-Volatile compounds. Utilizing HDS™ can also reduce the potential for contamination during field and lab leak checking. Data is presented detailing the advantages of HDS™, including comparisons with vacuum sampling canisters to show precision and sampling consistency.