| Indoor air is polluted heavily nowadays so people pay more attention to the indoor air testing. However, when indoor air is tested according to the GB50325-2001《Code for indoor environmental pollution control of civil building engineering》and the GB/T18883-2002《Indoor air quantity standard》, the domestic mixed reference gas cannot satisfy the need of TVOC testing now and it will pay more than $20,000 to import a bottle of reference gas from the United States. In this paper, the volatility organic compounds (VOCs) reference tube was studied with the commercial Tenax-TA blank tube in order to satisfy the need to the reference gas in indoor air testing. Firstly, the thermal desorption-gas chromatography method, on-line and off-line study method and so on were mainly used to study the reference tube, including the activation time, store, adsorbing the benzene series compounds of blank tube, active carbon tube's limitation to be reference tube, the best desorption time of Tenax-TA reference tube, the difference between on-line and off-line methods, the best injection time of gas chromatography and so on. The best conditions to study reference tube are as follows: choosing the commercial Tenax-TA blank tube, handling the tube for 20 minutes under the highly pure nitrogen current of 40mL/min after cutting it, sealing by the metal cap with polytetrafluoroethylene gasket, injecting the mixed reference aqua or gas to blank tube by on-line method, desorpting the tube for 10 minutes at 300℃, leading all the gas into the capillary pillar of the gas chromatography for 2 minutes. Secondly, under the best conditions , the work curve and adsorption-desorption efficiency of the reference tube were studied, the uncertainty of its content was assessed, its stability was investigated...
|
PDF Full Text Request