GB/T Translated English of Chinese Standard: GB/T NATIONAL STANDARD

Transcription

1 Translated English of Chinese Standard: GB/T GB NATIONAL STANDARD OF THE PEOPLE S REPUBLIC OF CHINA ICS Y 80 GB/T Determination of volatile organic compounds in furniture 家具中挥发性有机化合物的测定 Issued on: September 03, 2014 Implemented on: August 01, 2015 Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China; Standardization Administration of the PRC. Page 1 of 25

2 Table of contents Foreword Scope Normative references Terms and definitions Determination of formaldehyde Determination of benzene and total volatile organic compounds Appendix A (Normative) Safe sampling volume of benzene series Appendix B (Informative) Typical GC-MS total ion chromatogram of benzene series and volatile organic compounds References Page 2 of 25

3 Foreword This standard is drafted in accordance with the rules given in GB/T Please note that some of the contents of this document may involve patents. The issuer of this document does not assume responsibility for the identification of these patents. This standard was proposed by the China Light Industry Federation. This standard shall be under the jurisdiction of the National Furniture Standardization Technical Committee (SAC/TC 480). The main drafting organizations of this standard: Shenzhen Metrology and Quality Inspection Institute, Shanghai Quality Supervision and Inspection Technology Research Institute, State Furniture and Indoor Environment Quality Supervision and Inspection Center, Zhejiang Furniture and Hardware Research Institute, National Furniture Product Quality Supervision and Inspection Center (Chengdu), Jiangsu Product Quality Supervision and Inspection Research Institute, Shenzhen Huayuanxuan Furniture Co., Ltd., Hunan Xinggang Home Furnishing Development Co., Ltd. The participating drafting organizations of this standard: Minhua Furniture Manufacturing (Shenzhen) Co., Ltd., Tsinghua University. The main drafters of this standard: Wu Haitao, Zhang Shuyan, Li Weiheng, Zhang Xiaojie, Guo Hongzhi, Xiao Zheng, Zhang Xiaobo, Luo Xin, Liang Mijia, Li Longping, Zhu Yuhong, Liu Yunzheng, Chen Bihuang, Huang Xiaowei, Zhang Yinping, Hu Jie. Page 3 of 25

4 Determination of volatile organic compounds in furniture 1 Scope This standard specifies the test methods for the volatile organic compounds in furniture. This standard applies to the determination of formaldehyde, benzene and total volatile organic compounds in furniture. 2 Normative references The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this Standard. GB/T 601 Chemical reagent - Preparations of standard volumetric solutions GB/T 603 Chemical reagent - Preparations of reagent solution for use in test GB/T 6682 Water for analytical laboratory use - Specification and test methods 3 Terms and definitions The following terms and definitions apply to this document. 3.1 Volatile organic compounds (VOC) It refers to the organic compound released from the sample AND capable of being detected in the outlet gas of the test equipment. Note: The outlet of the test equipment refers to the gas outlet of the equipment that tests the release of volatile organic compounds from furniture, including sampling ports designed to collect gas samples. For example, when using the climate chamber method to test the volatile organic compound release from furniture, the outlet of the test equipment refers to the exhaust port of the climate chamber OR the sampling port of the climate chamber. Page 4 of 25

5 mol/l hydrochloric acid solution: MEASURE 9 ml of hydrochloric acid; DISSOLVE it in water; DILUTE it to 1000 ml % ammonium ferric sulfate solution: WEIGH 1.0 g of ammonium ferric sulfate [NH4Fe (SO4)2 12H2O]; USE 0.1 mol/l hydrochloric acid to dissolve it; DILUTE it to 100 ml Iodine solution [c (½I2) = 0.1 mol/l]: WEIGH 40 g of potassium iodide, DISSOLVE it into 25 ml of water; ADD 12.7 g of iodine. After the iodine is completely dissolved, USE water to make its volume reach to 1000 ml; TRANSFER it into a brown bottle; STORE it in the dark mol/l sodium hydroxide solution: WEIGH 40 g of sodium hydroxide; DISSOLVE it into water; and DILUTE it to 1000 ml mol/l sulfuric acid solution: TAKE 28 ml of concentrated sulfuric acid; slowly ADD it into water; after cooling, DILUTE it to 1000 ml Sodium thiosulfate standard titration solution [c(na2s2o3) = mol/l]: It may purchase standard reagent OR otherwise conduct preparation and calibration in accordance with the provisions of GB/T % starch solution: USE a small amount of water to make 0.5 g of soluble starch into a paste; ADD 100 ml of boiling water; BOIL it 2 min ~ 3 min until the solution is transparent; after cooling, ADD 0.1 g of salicylic acid or 0.4 g of zinc chloride; PRESERVE it Formaldehyde standard stock solution: TAKE 2.8 ml of 36% ~ 38% formaldehyde solution; PLACE it into a 1000 ml volumetric flask; ADD water to dilute it to the mark; SHAKE it uniformly; at this time, 1 ml of this solution equals to 1 mg of formaldehyde; AND its exact concentration is calibrated using the following iodometric method. It may also purchase standard reagent. Calibration of formaldehyde standard stock solution: Accurately MEASURE ml of formaldehyde standard stock solution to be calibrated; PLACE it in a 250 ml iodine volumetric flask. ADD ml of iodine solution ( ) and 15 ml of sodium hydroxide solution ( ); LET it standing for 15 min; ADD 20 ml of sulfuric acid solution ( ); LET it standing for 15 min again. USE the sodium thiosulfate standard titration solution ( ) to titrate it, until the solution shows pale yellow; ADD 1mL of starch solution ( ); CONTINUE titration until the blue color disappears; RECORD the volume of the sodium thiosulfate standard titration solution volume (V2) used. At the same time, USE water to do reagent blank titration; RECORD the volume of the sodium thiosulfate standard titration solution volume (V2) used for blank Page 6 of 25

6 Bg - Calculation factor obtained from the drawn standard curve ( ), in micrograms (μg); d - Dilution factor; V0 - Sampling volume after converted into the standard state, in liters (L). The calculation result is retained with two significant digits Measurement range, interference and exclusion Measuring range USE 5 ml of sample solution, AND the determination range of this method is 0.1 μg ~ 1.5 μg; if the sampling volume is 20 L, the determinable concentration range is 0.01 mg/m 3 ~ 0.15 mg/m Interference and exclusion The 20 μg phenol, 2 μg aldehyde and nitrogen dichloride have no interference with this method. The co-existence of the sulfur dioxide will make the determination result slightly low. Therefore, the interference from sulfur dioxide shall not be ignored; AND it may make the gas sample firstly pass through the manganese sulfate filter paper to remove the sulfur dioxide Precision Repeatability The absolute difference between the two independent test results obtained under the repeatability condition is not more than 20% of the arithmetic mean of the two determined values, based on the preconditions that the cases exceeding 20% of the arithmetic mean of the two determined values do not exceed 5% Reproducibility The absolute difference between the two independent test results obtained under the reproducibility condition is not more than 40% of the arithmetic mean of the two measured values, based on the preconditions that the cases exceeding 40% of the arithmetic mean of the two determined values do not exceed 5%. 4.2 Method 2: chromotropic acid spectrophotometry Principle Page 10 of 25

7 Standard gas PREPARE the mixed standard gas containing each compound gas component to be determined at concentration about 100 μg/m 3. It may also purchase the certified mixed standard gas Liquid standard substances Each solvent to be tested is chromatographic pure which is not affected by the compound that co-eluting with the compound to be tested Calibration of mixed solution USE the liquid standard substance of to prepare it; USE the methanol solution as the dilution solvent. It may also purchase the certified mixed standard gas A solution containing about 10 mg/ml of each liquid standard substance ADD 50 ml of methanol solution into a 100 ml volumetric flask; accurately WEIGH 1 g (accurate to g) of liquid standard substance into this volumetric flask; it may weigh and place several liquid standard substances into the same volumetric flask, AND start weighing from the liquid standard substance of the weakest volatility. USE the methanol solution to make the volume reach to the mark; SHAKE it uniformly. This standard solution is sealed and preserved in a 4 C refrigerator AND it can be stored for 1 month A solution containing about 1 mg/ml of each liquid standard substance ADD 50 ml of methanol solution into a 100 ml volumetric flask; accurately PIPETTE ml of the standard solution as prepared in accordance with ; USE methanol solution to make the volume reach to the mark; SHAKE it uniformly. This standard solution shall be prepared before use A solution containing about 100 μg/ml of each liquid standard substance ADD 50 ml of methanol solution into a 100 ml volumetric flask; accurately PIPETTE ml of the standard solution as prepared in accordance with ; USE methanol solution to make the volume reach to the mark; SHAKE it uniformly. This standard solution shall be prepared before use A solution containing about 10 μg/ml of each liquid standard substance Page 15 of 25

8 Note: The quality of the carrier gas is very important because the contaminants in the gas may be collected together with the tested substance in the cold trap. 5.3 Instruments and equipment Sampling tube: USE the sampling tube equipped with thermal desorption OR the inner wall polished stainless steel tube or glass tube of appropriate inner diameter and length; the sampling tube shall be marked to facilitate the identification of the sampling inlet; the both ends of the sampling tube may be sealed by the metal nut together with polytetrafluoroethylene ferrule, AND the sampling tube shall contain at least 200 mg of absorbent (5.2.3). All sampling tubes shall be subjected to activation treatment (5.4.1) before use. AND the thermal desorption temperature shall be lower than the activation temperature Syringe: 10 μl liquid syringe; 10 μl gas syringe; and 1 ml gas syringe Air sampler: Flow range 0 L/min ~ 0.5 L/min. The flow rate is stable and adjustable. Before and after sampling, it shall use the soap flow meter to calibrate the sampling flow, with the error less than 5% Piping: Polyethylene or Teflon tubing of appropriate diameter is used to ensure the connection and leak prevention of air samplers and sampling tubes. It is not allowed to use the plastic tube upstream of the sampling tube gas circuit. The tubing disturbance may lead in contaminant. As for the tubing used upstream of the gas circuit of the sampling tube, it shall check whether its inside contains contaminant that may interfere with determination before use Soap flow meter: it is used to calibrate the gas flow of the air sampler Atmospheric pressure gauge: same as Gas Chromatograph: equipped with mass spectrometer, with the minimum detection limit of at least 1 ng toluene Column: non-polar (polarity index less than 10) quartz capillary column; it may choose the quartz column of length 30 m ~ 60 m, inner diameter of 0.25 mm ~ 0.32 mm, and fixed phase thickness of 0.25 μm ~ 1.00 μm, AND the fixed phase may be 100% dimethylsiloxane or 5% phenyl, 1% vinyl, 94% methylsiloxane When detecting a specific volatile organic compound, it may be based on the characteristics of the compound to select appropriate column Thermal desorption device: it may conduct secondary thermal desorption against the sampling tube, AND lead the desorption gas into the gas chromatograph through inert gas. Page 17 of 25

9 5.6 Storage of sampling tubes The sampling tube shall be sealed and stored in a non-release room temperature vessel after sampling. In order to avoid possible changes, the sample shall be analyzed as soon as possible, preferably within 4 weeks after sampling. 5.7 Blank air sampling In accordance with the requirements of product standards, TAKE the blank air samples, the volume of which is equivalent to the sampling volume of sample. 5.8 Analytical procedures Two-stage thermal desorption, gas chromatography-mass spectrometry conditions Two-stage thermal desorption analysis conditions SELECT the thermal desorption temperature, time and gas flow rate, so that the cetane thermal desorption efficiency can reach to above 95%. Since the requirements for thermal desorption efficiency is related to the instrument used, only the basic parameters of the two-stage thermal desorption are given, AND the remaining parameters are set with reference to the guidelines for the use of the thermal desorption instrument. The parameters given below are the basic parameters: a) Thermal desorption temperature: 260 C ~ 280 C; b) Thermal desorption time: 5 min ~ 15 min; c) Thermal desorption gas flow rate: 30 ml/min ~ 50 ml/min; d) Cold trap: the maximum temperature: 280 C, the minimum temperature: -30 C, adsorbent: same as that used in the sampling tube, 40 mg ~ 100 mg; e) Transmission line temperature: 220 C ~ 250 C; f) Split ratio: the split ratio between sampling tube and the two-stage cold trap as well as between the two-stage cold trap and the analytical column shall be selected in accordance with the mass of the volatile organic compounds in the sampling tube Gas chromatography-mass spectrometry conditions Page 19 of 25

10 5.9 Results calculation USE the equation (2) to convert the sampling volume into the sampling volume under standard state Concentration of benzene series and volatile organic compounds in the sample gas is calculated in accordance with the equation (5). As for the component concentration of the volatile organic compounds without standard curve or which cannot be qualitative, it shall be calculated in accordance with the response coefficient of toluene: Where: C - Component concentration of benzene series and volatile organic compounds in the sample gas under standard state, in milligrams per cubic meter (mg/m 3 ); mf - Mass of the benzene series and volatile organic compounds as collected in the sampling tube, in milligrams (mg); mb - Mass of the benzene series and volatile organic compounds in blank tubes, in milligrams (mg); V0 - Sampling volume converted into the standard state, in liters (L). The result is retained with three digits after the decimal point Calculation of concentration of total volatile organic compounds (TVOC) in sample gas It shall analyze all the compounds of the retention time between n-hexane and n-hexadecane, including n-hexane and n-hexadecane It shall, in accordance with the standard curve, to conduct qualitative and quantitative against the component of the volatile organic compounds as much as possible, AND at least 10 highest peaks. The sum of the component concentrations of the all these volatile organic compounds of retention time between n-hexane and n-hexadecane, including n-hexane and n-hexadecane, is the TVOC concentration, with the results expressed as two digits after the decimal point Method features Lower detection limit Page 21 of 25

11 References [1] GB/T Methods for determination of formaldehyde in air of public places [2] HJ Ambient air - Determination of benzene and its analogies using sorbent absorption thermal desorption and gas chromatography [3] ASTM D Standard Test Method for Determining Formaldehyde Concentration in Air from Wood Products Using a Small Scale Chamber [4] ISO : 2004 (E) Indoor air - Part 6: determination of volatile organic compounds in indoor and test chamber air by active sampling on Tenax sorbent, thermal desorption and gas chromatography using MS/FID [5] ISO : 2001 Indoor, ambient and workplace air-sampling and analysis of volatile organic compounds by sorbent tube/thermal desorption/capillary gas chromatography - Part 1: Pumped sampling [6] BIFMA M Standard Test Method For Determining VOC Emissions From Office Furniture Systems, Components And Seating END Page 25 of 25