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室內(nèi)空氣中TVOC分析  測(cè)試譜圖：




TVOC analysis in indoor air
Analysis of TVOC in indoor air Details:

As indoor air pollution is becoming more and more serious, indoor air testing has attracted more and more attention. Combined with actual testing work, in view of the insufficiency of GB50325-2001 "Code for Indoor Environmental Pollution Control of Civil Construction Engineering" and GB/T18883-2002 "Indoor Environmental Quality Standards" for the detection of benzene and TVOC, a more in-depth study of analytical methods was made, and self-made The sampling tube low-temperature control device and the low-temperature glass bead dehumidification device can obtain accurate analysis data of benzene and TVOC at the same time for one sampling and one injection.

In addition, according to testing needs, liquid VOCs standard materials were prepared, and the best conditions for making standard series tubes were studied. The thermal desorption and capillary gas chromatography specified in GB50325-2001 and GB/T18883-2002, in the sampling conditions of the Tenax adsorption tube used in the field, the sampling flow rate is 0.5L/min, the sampling time is 20min, and the sampling temperature is not specified. , The experimental operating conditions are unclear or unreasonable, which affects the accuracy and reproducibility of the measurement results.

Haohan Chromatography (Shandong) Applied Technology Development Co., Ltd. conducted an in-depth study on this and found that the temperature of the sampling tube, the sampling flow rate and the sampling time all have a significant impact on the adsorption recovery rate of benzene series. It is found that the humidity conditions in the air also have a great influence on the recovery rate of VOCs. In the actual sampling process, it was found that only controlling the temperature of the sampling tube, the recovery rate of benzene was less than 90%, and when sampling at low temperatures, the FID detector was often turned off. . By adding a low-temperature glass bead tube in front of the sampling tube to dehumidify, good results are achieved. Use low-temperature glass beads to dehumidify, control the sampling temperature of the adsorption tube to about 5℃, the sampling flow rate at 200mL/min, and the sampling time for 10min, and use a secondary thermal desorption instrument to directly inject into the gas chromatograph. Under the above optimal sampling conditions, TVOC can be guaranteed The recovery rate of adsorption thermal desorption of all components can reach more than 90%, especially the sampling recovery rate of benzene has been greatly improved.

TVOC analysis test spectrum in indoor air: