本標準規定了測定氣態制冷劑中三氟甲烷（HFC-23）、二氟甲烷（HFC-32）、五氟乙烷（HFC-125）、1,1,1-三氟乙烷（HFC-143a）、二氯二氟甲烷（CFC-12）、一氯二氟甲烷（HCFC-22）、1,1,1,2-四氟乙烷（HFC-134a）、1,1-二氟乙烷（HFC-152a）、1-氯-1,2,2,2-四氟乙烷（HCFC-124）和 1-氯-1,1-二氟乙烷（HCFC-142b）等 10 種鹵代烴的氣相色譜-質譜法。

      本標準適用于氣態制冷劑中 HFC-23、HFC-32、HFC-125、HFC-143a、CFC-12、HCFC-22、HFC-134a、HFC-152a、HCFC-124 和HCFC-142b 體積分數的測定，不適用于上述化合物純度的測定。

      當取樣量為 20.0 μl，10 種鹵代烴的方法檢出限為 0.08%～0.09%；測定下限為 0.32%～0.36%。詳見附錄 A。

      本標準引用了下列文件或其中的條款。凡是注明日期的引用文件，僅注日期的版本適用于本標準。凡是未注日期的引用文件，其新版本（包括所有的修改單）適用于本標準。

      GB/T 3723 工業用化學產品采樣安全通則

      GB/T 6678 化工產品采樣總則

      GB/T 6681 氣體化工產品采樣通則

      GB/T 26571 特種氣體儲存期規范

      GB/T 37994 混合制冷劑采樣通則

      SN/T 2537 進出口制冷劑檢驗取樣方法

      下列術語和定義適用于本標準。

3.1

      制冷劑 refrigerant

      在制冷系統中用于傳遞熱量的流體，在低溫低壓環境吸收熱量，在高溫高壓環境釋放熱量，通常伴有相變過程。

3.2

      氣態制冷劑 gaseous refrigerant

      在溫度 20 ℃和壓力 101.3 kPa 下呈氣態的制冷劑。

      在一定的溫度條件下，樣品中的目標化合物在頂空進樣瓶中混合并達到平衡后，經氣相色譜分離，質譜檢測器檢測。通過與標準物質保留時間和質譜圖相比較進行定性，內標法定量。

      除非另有說明，分析時均使用符合國家標準的分析純試劑。實驗用水為不含目標化合物的二次蒸餾水或通過純水設備制備的水。

5.1 三氟甲烷（HFC-23），純度≥99.5%，存儲于鋼瓶中，參照證書相關說明保存。

5.2 二氟甲烷（HFC-32），純度≥99.5%，存儲于鋼瓶中，參照證書相關說明保存。

5.3 五氟乙烷（HFC-125），純度≥99.5%，存儲于鋼瓶中，參照證書相關說明保存。

5.4 1,1,1-三氟乙烷（HFC-143a），純度≥99.5%，存儲于鋼瓶中，參照證書相關說明保存。

5.5 二氯二氟甲烷（CFC-12），純度≥99.0%，存儲于鋼瓶中，參照證書相關說明保存。

5.6 一氯二氟甲烷（HCFC-22），純度≥99.6%，存儲于鋼瓶中，參照證書相關說明保存。

5.7 1,1,1,2-四氟乙烷（HFC-134a），純度≥99.5%，存儲于鋼瓶中，參照證書相關說明保存。

5.8 1,1-二氟乙烷（HFC-152a），純度≥99.5%，存儲于鋼瓶中，參照證書相關說明保存。

5.9 1-氯-1,2,2,2-四氟乙烷（HCFC-124），純度≥99.5%，存儲于鋼瓶中，參照證書相關說明保存。

5.10  1-氯-1,1-二氟乙烷（HCFC-142b），純度≥99.5%，存儲于鋼瓶中，參照證書相關說明保存。

5.11  內標化合物：1,1,1,2,3,3,3-七氟丙烷（HFC-227ea），純度≥99.6%，存儲于鋼瓶中，參照證書相關說明保存。

5.12 4-溴氟苯（BFB）溶液：ρ(C6H4BrF)=25 mg/L，溶劑為甲醇的市售有證標準溶液，按照標準溶液證書相關說明保存。

5.13 氮氣，純度≥99.999%。

5.14 載氣：氦氣，純度≥99.999%。

6.1 取樣導管：采用不銹鋼或其他耐腐蝕金屬管或聚四氟乙烯塑料管制作而成。取樣前，將取樣導管置于 110 ℃烘箱中烘烤 1 h，取樣結束后應及時拆卸取樣導管并妥善保管。保持導管清潔干燥，防止雜物或污物進入。現場樣品采集時，用于連接大型鋼瓶或集裝壓力儲罐與氣袋（6.2）；實驗室試樣制備時，用于連接裝有減壓閥（6.3）的小鋼瓶樣品與氣袋（6.2）。

6.2 氣袋：氟聚合物薄膜氣袋或鋁塑復合膜氣袋，帶微量注射器取樣閥，具可接取樣導管（6.1）連接頭，取樣閥同時具備開啟和關閉氣袋功能。

6.3 減壓閥：安裝于樣品小鋼瓶瓶口，用于實驗室取樣時的氣體減壓。

6.4 氣相色譜-質譜儀：色譜部分具有分流/不分流進樣口，柱溫箱可程序升溫；質譜部分具有 70 eV 電子轟擊離子源。

6.5 頂空自動進樣器：具備定量環或進樣針進樣功能。

6.6 頂空進樣瓶：瓶體為玻璃材質，密封墊為聚四氟乙烯/硅橡膠材質，密封蓋為螺旋蓋或一次性壓蓋， 20 ml，或與頂空自動進樣器（6.5）配套的玻璃瓶。使用前擰（壓）緊密封蓋，確保頂空進樣瓶的氣密性。

6.7 色譜柱：多孔層開管毛細管柱，60 m（柱長）×0.32 mm（內徑），固定相為鍵合硅膠，或其他等效毛細管柱。

6.8 注射器：氣密性注射器，玻璃材質，10.0 μl，25.0 μl，250 μl，500 μl，100 ml。

6.9 一般實驗室常用儀器和設備。

7.1 樣品采集與保存

      樣品采集前首先了解采集樣品的實際情況，樣品采集參照GB/T 6678、GB/T 6681和GB/T 37994相關規定執行，樣品保存參照GB/T 26571和SN/T 2537相關規定執行。

      樣品存儲于非重復充裝鋼瓶或重復充裝鋼瓶（容積W10 L,以下簡稱“小鋼瓶”）時，按生產批次抽取，同一批號抽取1瓶小鋼瓶樣品，運回實驗董；樣品存儲于貯槽、槽車或重復充裝鋼瓶（容積＞10L）時，同一批號抽取1罐（瓶）采樣，采樣時，將取樣導管（6.1）的一端與樣品容器的采樣口閥門連接，另一端與氣袋（6.2）連接，打開閥材樣品緩慢導入氣袋（6.2）,采樣后，擰緊氣袋閥門，采集2份平行樣品，1份用于分析，1份作為留樣保存。

      采集的小鋼瓶樣品在常溫密封條件下運輸和保存，在裝卸運輸過程中，嚴禁撞擊、拖拉、摔落和直接暴曬，應在陰涼干燥的地方存放,房間通風條件良好,不得靠近熱源,嚴禁日曬雨淋;采集到氣袋（6.2）的樣品在常溫下避光運輸和保存，并存放在陰涼干燥的地方，7 d內檢測完畢。

      注：使用氣袋釆樣前，應檢查并確保氣袋（6.2）密封性良好；用氮氣（5.13）清洗3次后備用；采樣時，先用樣品氣清洗氣袋（6.2） 3次，再釆集樣品.

7.2 試樣的制備

      小鋼瓶樣品：先用氮氣（5.13）清洗氣袋（6.2） 3次，再用樣品置換氣袋（6.2） 3次，待用。將減壓閥（6.3）連接小鋼瓶，緩慢打開小鋼瓶的閥門及減壓閥（6.3）,放出樣品以置換減壓閥（6.3）管路中氣體。隨后立即用取樣導管（6.1）連接減壓閥（6.3）和清洗后的氣袋（6.2）,打開減壓閥（6.3）,

      讓適量的氣體樣品轉移氣袋（6.2）中。小鋼瓶樣品取樣示意圖見圖1。使用氣密性注射器（6.8）從上述氣袋中移取20.0 M樣品經密封墊扎入頂空進樣瓶（6.6）中，向頂空進樣瓶（6.6）中加入1,1,1,2,3,3,3-七氟丙烷內標（5.11） 10.0μl,待測。

毛細管柱測氣態制冷劑 10 種鹵代烴  測試譜圖：




Capillary column measurement of gaseous refrigerants 10 kinds of halogenated hydrocarbons
Capillary column measurement of gaseous refrigerants 10 kinds of halogenated hydrocarbons Details:

Name: Capillary Column
Specification: 60m*0.32mm
Model: Porous layer open tube capillary column PLOT silica gel
Application: gaseous refrigerant determination of 10 halogenated hydrocarbons gas chromatography-mass spectrometry

1 Scope of application


      This standard specifies the determination of trifluoromethane (HFC-23), difluoromethane (HFC-32), pentafluoroethane (HFC-125), 1,1,1-trifluoroethane (HFC- 143a), dichlorodifluoromethane (CFC-12), monochlorodifluoromethane (HCFC-22), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1-difluoroethane 10 kinds of halogens including HFC-152a, 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124) and 1-chloro-1,1-difluoroethane (HCFC-142b) Gas Chromatography-Mass Spectrometry of Substituted Hydrocarbons.

      This standard applies to the volume fraction of HFC-23, HFC-32, HFC-125, HFC-143a, CFC-12, HCFC-22, HFC-134a, HFC-152a, HCFC-124 and HCFC-142b in gaseous refrigerants. The determination is not suitable for the determination of the purity of the above-mentioned compounds.

      When the sampling volume is 20.0 μl, the detection limit of the method for 10 halogenated hydrocarbons is 0.08%～0.09%; the lower limit of determination is 0.32%～0.36%. See Appendix A for details.

2 Normative references


      This standard refers to the following documents or their clauses. For dated reference documents, only the dated version is applicable to this standard. For undated reference documents, the latest version (including all amendments) is applicable to this standard.

      GB/T 3723 General rules for the sampling safety of industrial chemical products

      GB/T 6678 General Rules for Sampling of Chemical Products

      GB/T 6681 General Rules for Sampling of Gas Chemical Products

      GB/T 26571 Special Gas Storage Period Specification

      GB/T 37994 General Rules for Sampling of Mixed Refrigerants

      SN/T 2537 Sampling method for import and export refrigerant inspection

3 Terms and definitions


      The following terms and definitions apply to this standard.

3.1

      Refrigerant

      The fluid used to transfer heat in the refrigeration system absorbs heat in a low-temperature and low-pressure environment, and releases heat in a high-temperature and high-pressure environment, usually accompanied by a phase change process.

3.2

      Gaseous refrigerant

      It is a gaseous refrigerant at a temperature of 20 ℃ and a pressure of 101.3 kPa.

4 Principles of the method


      Under certain temperature conditions, the target compounds in the sample are mixed in the headspace sample bottle and reach equilibrium, then separated by gas chromatography and detected by a mass detector. It is qualitatively compared with the retention time of the standard substance and the mass spectrum, and quantified by the internal standard method.

5 Reagents and materials


      Unless otherwise specified, analytical reagents conforming to national standards are used for analysis. The experiment water is double distilled water without target compound or water prepared by pure water equipment.

5.1 Trifluoromethane (HFC-23), purity ≥99.5%, stored in a steel cylinder, refer to the relevant instructions of the certificate for storage.

5.2 Difluoromethane (HFC-32), purity ≥99.5%, stored in a steel cylinder, refer to the relevant instructions of the certificate for storage.

5.3 Pentafluoroethane (HFC-125), purity ≥99.5%, stored in a steel cylinder, refer to the relevant instructions of the certificate for storage.

5.4 1,1,1-Trifluoroethane (HFC-143a), purity ≥99.5%, stored in a steel cylinder, refer to the relevant instructions of the certificate for storage.

5.5 Dichlorodifluoromethane (CFC-12), purity ≥99.0%, stored in a steel cylinder, refer to the relevant instructions of the certificate for storage.

5.6 Monochlorodifluoromethane (HCFC-22), purity ≥99.6%, stored in a steel cylinder, refer to the relevant instructions of the certificate for storage.

5.7 1,1,1,2-Tetrafluoroethane (HFC-134a), purity ≥99.5%, stored in a steel cylinder, refer to the relevant instructions of the certificate for storage.

5.8 1,1-Difluoroethane (HFC-152a), purity ≥99.5%, stored in a steel cylinder, refer to the relevant instructions of the certificate for storage.

5.9 1-Chloro-1,2,2,2-tetrafluoroethane (HCFC-124), purity ≥99.5%, stored in a cylinder, refer to the relevant instructions of the certificate for storage.

5.10 1-Chloro-1,1-difluoroethane (HCFC-142b), purity ≥99.5%, stored in a steel cylinder, refer to the relevant instructions of the certificate for storage.

5.11 Internal standard compound: 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), purity ≥99.6%, stored in a cylinder, refer to the relevant instructions of the certificate for storage.

5.12 4-Bromofluorobenzene (BFB) solution: ρ(C6H4BrF)=25 mg/L, the solvent is a commercially available certified standard solution of methanol, and it should be stored in accordance with the relevant instructions of the standard solution certificate.

5.13 Nitrogen, purity ≥99.999%.

5.14 Carrier gas: helium, purity ≥99.999%.

6 Apparatus and equipment


6.1 Sampling catheter: made of stainless steel or other corrosion-resistant metal pipes or polytetrafluoroethylene plastic pipes. Before sampling, place the sampling catheter in a 110 ℃ oven for 1 hour. After sampling, the sampling catheter should be removed in time and kept properly. Keep the catheter clean and dry to prevent debris or dirt from entering. For on-site sample collection, it is used to connect large steel cylinders or container pressure storage tanks and air bags (6.2); for laboratory sample preparation, it is used to connect small steel cylinder samples equipped with pressure relief valves (6.3) and air bags (6.2). ).

6.2 Air bag: fluoropolymer film air bag or aluminum-plastic composite film air bag, with a micro-syringe sampling valve, with a sampling tube (6.1) connector, the sampling valve has the function of opening and closing the air bag at the same time.

6.3 Pressure reducing valve: installed at the mouth of the sample small steel bottle, used for gas pressure reduction during laboratory sampling.

6.4 Gas Chromatograph-Mass Spectrometer: The chromatographic part has a split/splitless inlet, and the column oven can be programmed to increase temperature; the mass spectrometer has a 70 eV electron bombardment ion source.

6.5 Headspace autosampler: It has the function of sampling loop or injection needle.

6.6 Headspace sampling bottle: the bottle body is made of glass, the sealing gasket is made of PTFE/silicone rubber, and the sealing cap is screw cap or disposable gland, 20 ml, or with the headspace autosampler (6.5) Matching glass bottle. Tighten (press) the sealing cap before use to ensure the air tightness of the headspace sample bottle.

6.7 Chromatographic column: a porous layer open-tube capillary column, 60 m (column length) × 0.32 mm (inner diameter), the stationary phase is bonded silica gel, or other equivalent capillary columns.

6.8 Syringe: air-tight syringe, glass material, 10.0 μl, 25.0 μl, 250 μl, 500 μl, 100 ml.

6.9 Commonly used instruments and equipment in general laboratories.

7 samples


7.1 Sample collection and storage

      Before sample collection, first understand the actual situation of the collected samples. For sample collection, refer to the relevant regulations of GB/T 6678, GB/T 6681 and GB/T 37994, and for sample storage, refer to the relevant regulations of GB/T 26571 and SN/T 2537.

      When the samples are stored in non-refillable cylinders or refilled cylinders (volume W10 L, hereinafter referred to as "small cylinders"), they shall be taken according to the production batch, and one small cylinder sample shall be taken from the same batch number and transported back to the laboratory; the samples shall be stored in When storing tanks, tank trucks or refilling steel cylinders (volume> 10L), one can (bottle) is sampled from the same batch number. When sampling, connect one end of the sampling pipe (6.1) to the sampling port valve of the sample container, and the other end to Connect the air bag (6.2), open the valve material and slowly introduce the sample into the air bag (6.2). After sampling, tighten the valve of the air bag to collect 2 parallel samples, 1 for analysis, and 1 for storage.

      The collected small steel cylinder samples are transported and stored under sealed conditions at room temperature. During the loading and unloading process, impact, drag, drop and direct exposure are strictly prohibited. They should be stored in a cool and dry place. The room is well ventilated and should not be close to heat sources. Sun and rain; the samples collected in the air bag (6.2) should be transported and stored in the dark at room temperature and stored in a cool and dry place. The test will be completed within 7 days.

      Note: Before using the air bag for sampling, check and ensure that the air bag (6.2) is well sealed; clean with nitrogen (5.13) for 3 times and then reserve; when sampling, first clean the air bag (6.2) with sample gas for 3 times, and then Collect samples.

7.2 Preparation of test samples

      Small cylinder sample: first clean the air bag (6.2) with nitrogen (5.13) 3 times, then replace the air bag (6.2) with the sample 3 times, and then set aside. Connect the pressure reducing valve (6.3) to the small steel cylinder, slowly open the valve of the small steel bottle and the pressure reducing valve (6.3), and release the sample to replace the gas in the pipeline of the pressure reducing valve (6.3). Then immediately connect the pressure reducing valve (6.3) and the cleaned air bag (6.2) with the sampling pipe (6.1), open the pressure reducing valve (6.3),

      Transfer an appropriate amount of gas sample to the gas bag (6.2). See Figure 1 for a schematic diagram of sample sampling from a small steel cylinder. Use an air-tight syringe (6.8) to remove a 20.0 M sample from the above air bag and put it into the headspace sample vial (6.6) through a sealing gasket, and add 1,1,1, to the headspace sample vial (6.6). 2,3,3,3-Heptafluoropropane internal standard (5.11) 10.0μl, to be tested.


Capillary column test gaseous refrigerant 10 kinds of halogenated hydrocarbon test spectrum: