Charcoal trap

Helium [7440-59-7] M 4.0. Dried by passage through a column of Linde 5A molecular sieves and CaS04, then passed through an activated-charcoal trap cooled in liquid N2, to adsorb N2, argon, xenon and krypton. Passed over CuO pellets at 300° to remove hydrogen and hydrocarbons, over Ca chips at 600° to remove oxygen, and then over titanium chips at 700° to remove N2 [Arnold and Smith 7 Chem Soc, Faraday Trans 2 77 861 1981]. 

Air samples can be analyzed by passing a known volume of air through a Teflon filter to catch air particulates followed by an activated charcoal filter to trap any gas-phase materials. The Teflon filters are extracted with hexane, concentrated, and analyzed by GC/MS. The charcoal traps are desorbed with carbon disulfide, concentrated, and analyzed by GC/MS. No performance data were reported (Dannecker et al. 1990). 

The instruments include an ionization chamber, the charcoal-trap technique, a flow-type ionization chamber (pulse-counting technique), a two-filter method, an electrostatic collection method and a passive integrating radon monitor. All instruments except for the passive radon monitor have been calibrated independently. Measurements were performed... 

Charcoal-Trap Method (ACC). The Charcoal-Trap Method has been used for sampling radon gas in the atmospheric air and for measuring radon emanation rate from the soil surface by some researchers (e. g. 

After the third extraction, we measure the radon and its yield by adding several cc STP of carrier Ar to the melt water with He to 1.3-atm pressure and allow the radon to build up for 4 days. We also replace the spiral glass C02 trap with a charcoal trap to insure the collection of the carrier Ar with the radon. We then He-purge the water and collect the Rn with the carrier Ar on the charcoal at liquid air temperature. The Ar plus Rn is recovered from the charcoal at 300 °C purified over hot Ti and counted in a proportional counter. 

Kester [5] has discussed the application of the purge and trap gas chromatographic method to the determination of aliphatic chloro-compounds in soil. Following methanol extraction of the soil the extract is gas purged and the purge gases trapped on a Tenax silica gel/ charcoal trap followed by thermal desorption from the trap and examination by gas chromatography and mass spectrometry. Compounds that have been determined by this method are listed in Table 5.1. 

The pentafluoride products are easily recovered by vacuum evaporation of the HF, SiF4, and excess MF6. These volatile substances are passed through soda-lime and charcoal traps to scrub the HF and MF6. For each hexafluoride a... 

A DuPont model 21-492B GC/MS with an Incos data system was used to confirm the presence of thiazolidine and nitrosated thiazolidine. A 30 m x 0.24 mm id glass capillary column coated with SP-2250 was used for GC/MS analyses with a 30 1 split ratio (with the larger fraction vented to atmosphere through a charcoal trap). Electron impact ionization was used at 70 eV. The data system generated total ion current chromatograms and recorded mass spectra. 

G. Reineccius and R. Liardon, The use of charcoal traps and micro-wave desorption for the analysis of headspace volatiles above heated thiamine solutions, Top. Flavour Res. Proc. Int. Conf., 1985, pp. 125-136. 

Spectral subtraction and spectral search aid the identification of evolved gases, which are often a mixture of products. Nevertheless, for unambiguous identification of unknown volatiles more powerful methods are required. Jansen and co-workers [86] have incorporated a parallel mass spectrometer onto the FTIR stage of a thermogravimetry-FTIR (TG-FTIR). The sample is thermally decomposed by TGA and the products collected in a Tenax (absorbent charcoal) trap. After desorption, the products are separated by a GC and the sample split, with 99% going to the IR spectrometer and 1% to the mass spectrometer. 

The correct management of the various gaseous, liquid and solid wastes determines the regularity of production. The gaseous wastes flow through exhaust systems equipped with absolute filters and soda lime and activated charcoal traps. They are discharged into the atmosphere after analysis of their krypton 85 and iodine content. The liquid wastes from the various cells are stored in 1 nr tanks (located in Petrus) and removed periodically by a shielded tank truck for transport to a liquid waste treatment station in another C.E.A. center. 

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