Toxic and harmful substances in indoor air will damage the health of the human body. The Code for Environmental Pollution Control in Civil Construction Engineering uses bismuth, formaldehyde, ammonia benzene and volatile organic compounds (TVOC) and free toluene diisocyanate (TDI) as primary pollutants. .
Total Volatile Organic Compound (TVOC) is the total amount of volatile organic compounds (both xylene, etc.) measured at atmospheric pressure below 250 °C under normal pressure conditions.
The indoor air pollutant detection (TVOC) analysis solution of Beijing Huasheng Spectrum Instrument Co., Ltd. is based on the requirements of the Ministry of Construction's "Code for the Control of Environmental Pollution in Civil Buildings" by gas chromatography, quantitative detection (TVOC) and benzene. content.
Dedicated gas chromatograph configuration for indoor environment (TVOC) testing:
equipment name | Models and Specifications | unit | Quantity |
Gas Chromatograph | Host + FID + filling system + capillary system | station | 1 |
Host + FID + filling system Host + FID + capillary system | station | 2 | |
Chromatography workstation | BF-2002 TVOC Special Edition Dual Channel | station | 1 |
Air generator | 0～3000ml/min | station | 1 |
Hydrogen generator | 0～310ml/min 99.999% | station | 1 |
nitrogen bottle | High purity nitrogen 99.999% with pressure reducing valve | set | 1 |
ATDS-6000 Thermal Desorber | Analytical-activated 6-tube-simulation sampling-backflushing machine | station | 1 |
Spectrophotometer | Detection of formaldehyde and ammonia | station | 1 |
Measuring instrument | FD216 | station | 1 |
Dual gas path sampler | QC series 0.1～1.5L/min; continuous adjustable timing: 1～99min | station | 1 |
QC-6H constant current sampling flow: 0.4~0.6L/min | station | 1 | |
BS-H2 constant current Working flow range: 100～500ml/min | station | 1 | |
Empty box pressure gauge | DYM3 | station | 1 |
thermometer | TES1360 | station | 1 |
Digital blast drying oven | 9030MBE | station | 1 |
Quartz double distilled water meter | SZ-93 | station | 1 |
Electronic balance | Accuracy: 0.1mg; weighing range: 200g | station | 1 |
Sample box | Packing equipment such as absorption tube and sampling tube; equipped with aluminum alloy bracket | One | 1 |
TVOC special column | US KB 0.32mm*50m*1u | support | 1 |
Benzene special column | 3mm*2M | support | 1 |
Tenax adsorption tube | 200mg 50pcs/box (quantity optional) | box | 1 |
Activated carbon sampling tube | 50 sticks/package (quantity optional) | package | 1 |
Bubble absorber | 10ml (optional) | support | 1 |
Glass plate absorber | 10ml (optional) | support | 1 |
TVOC standard solution | 10, 100, 1000ug/ml | set | 1 |
Benzene standard solution | 2ml | support | 1 |
Benzene standard gas | 2L 5 components | bottle | 1 |
Phenol reagent | 5g | bottle | 1 |
Formaldehyde solution | 20ml 100mg/L or 2ml 10.2mg/ml | support | 1 |
Ammonia solution | 20ml 500mg/L | support | 1 |
The specific analysis conditions and processes are as follows:
1. Use the atmospheric sampler and TVOC adsorption tube to sample on site: 0,5L/min for 20min or 10L atmosphere. That is, the 10L atmosphere passes through the adsorption tube at a flow rate of 0,5 L/min, and the total volatile organic compounds in the air are adsorbed in the adsorption tube and brought into the laboratory for detection;
2. Start the gas chromatograph: 0,32mm*50mTVOC capillary column; FID: 260°C; vaporization: 260°C; column chamber: 50°C constant for 10min, rise to 250°C at 5°C/min; 250°C to peak output; Sensitivity and attenuation: 103*1; calibration: 1μL of each standard content of 100mg/mL was calibrated to the adsorption tube with a scaler, and blown with 100mL/minN2 for 5min, this tube is the standard adsorption tube; Thermal desorption temperature: 300 ° C, pyrolysis for 30 seconds, after 5 minutes of injection, return to the pyrolysis instrument, the split ratio is 50:1
3. According to the above conditions, the standard adsorption tube is first prepared. After the drawing, the calibration curve (factor) is obtained by the external standard method, and then the TVOC chromatogram in the adsorption tube is sampled and qualitatively quantified under the same chromatographic conditions.
4. Calculation: a According to the above method, the content M of each component of TVOC in the sampling tube can be directly obtained in the integral result table, and the unit is μg;
b Find the total amount of TVOC M total = M1 + M2 + M3 + - - Mi + M (g). The total amount includes a set volatile content M = f (toluene) × ∑ A, that is, the amount of the unidentified substance is calculated as the correction factor of toluene.
c find the actual total TVOC of the air M = M total - M blank total
d Determine the concentration of TVOC in the measured indoor air C == M real (μg) / V0 (L) (mg / m3)
V0 is the sampling volume corrected to the standard state, V0==V mining × (T0/273+t) × (P/P0) (L)
5. Judgment and report: According to the calculation result, C is judged according to the GB index, and the conclusion is drawn and a report is issued.
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