Test procedures for using a cubic VOC climate and environment test box
(1) Measurement of cabin background concentration
The environmental test cabin doors cleaned by B2 will be closed and opened for operation. Taking the closing time of cabin doors as zero time, the test time is 24 hours (+1 h). The concentration of the cabin background after 24 hours of cabin closure is determined. The total volatile organic compounds (TvOC) release is 6 L. The average cabin background concentration of two parallel samples collected for each test should be in accordance with the requirements of B112f, if not in accordance with the weight of B21. Repeat.
(2) specimen placement
The specimen prepared according to B.33 should be placed in the middle of the environmental test chamber. The emission surface should be horizontal upward so that air flow can pass through the surface of the test chamber evenly. However, the specimen should not fall on the surface of the chamber, and the environmental test chamber should be closed quickly to start the test.
(3) Test time
The test time is 72 h (+1 h) when the specimen is put into the cabin at 0 hour.
(4) Sampling
1. When sampling total volatile organic compounds (TVOC), the constant current sampler should be adjusted in the range of 200 mL/min (the sampling velocity is less than 80% of the intake velocity), and the sampling volume is 6L. At the same time, the sampling temperature and atmospheric pressure of sampling flow should be recorded.
2. Take off the adsorption tube after sampling, seal both ends of the adsorption tube and mark them well, then put them into sealed metal or glass containers, and analyze them as soon as possible within 7 days.
(5) Analysis
1. Selecting external standard method for total volatile organic compounds (TvOC) analysis, we should first extract standard solution of 1_L~5_L and inject the standard solution of 0.05 g, 0.1 Hg, 0.5 ug, 1.0 UG and 20_g into Tenax-TA adsorption tube with nitrogen of 100 mL/min through the adsorption tube. After 3 minutes, we should remove and seal the adsorption tube to complete the preparation of standard series.
2. The standard series of gas chromatographic analysis adsorbent tubes with direct thermal analysis sampling should be placed in the thermal desorption pack. After full analysis of the adsorbent tubes in the temperature range of 280 300 C, the analytic gases can be directly entered into the gas chromatograph by the injection valve for gas chromatographic analysis, so as to retain the time for qualitative analysis and quantify the peak area. The content (mg) of each component was taken as abscissa and the peak area was taken as ordinate. The standard curve was drawn and the regression equation was calculated.
3. In the analysis of test samples, each sample adsorption tube should be analyzed according to the same thermal analysis gas chromatography method as the standard series, in order to retain the qualitative time and quantify the peak area.
Note 1: For unrecognized peaks in the test process, toluene should be used for quantitative calculation.
Note 2: When the unknown interferes with the determination, it is advisable to reduce the interferences to * by choosing appropriate gas chromatography column, sampling absorption tube or adjusting the conditions of the analysis system.
