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1、空气中苯、甲苯和二甲苯的测定溶剂解吸-气相色谱法实习 指导老师：郑 丹MOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public Health【目的和要求】 掌握气相色谱法测定空气中苯、甲苯和二甲苯的基本原理和操作技术； 熟悉气相色谱仪器的基本操作
2、和参数设置； 了解玻璃毛细管色谱住条件的优化；出峰时间定性的方法。MOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public Health【原理】 空气中的苯、甲苯、二甲苯用活性碳管采集，二硫化碳解吸后进样，经色谱柱分离，氢焰离子化检测器检测，以保
3、留时间定性，峰面积定量。 MOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public Health【仪器及试剂】1. 活性碳采样管：675mm，溶剂解吸型，内装100mg/50mg 活性碳。2. 空气采样器：QC-2B型大气采样仪，流量0.1-1.
4、5L/min。3. 玻璃器皿：具塞比色管，10ml；移液管，10mL，微量注射器：10、5l。4.二硫化碳：色谱鉴定无干扰杂峰。5. 苯、甲苯和二甲苯：分析纯，纯度99.5%以上。 MOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public Hea
5、lthMOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public HealthMOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & H
6、ealth, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public Health 6.气相色谱仪（GC Agilent 6890N）条件：进样口250，分流比（30.0：1），载气：高纯氮气，玻璃毛细管柱：HP-5毛细管色谱柱，恒流模式，流量：1.2ml/min。柱温 80，保持7min。氢焰离子化检测器（FID）：300。MOE Key Laboratory of Environmental & Health, MOE
7、Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public HealthMOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute
8、 of Environmental Medicine, School of Public HealthSchool of Public HealthMOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public Health【分析步骤分析步骤】1.1.
9、样品处理：将采过样的前后段活性碳分别放入溶样品处理：将采过样的前后段活性碳分别放入溶剂解吸瓶中，各加入剂解吸瓶中，各加入1.0ml1.0ml二硫化碳，塞紧管塞，二硫化碳，塞紧管塞，振摇振摇1min1min，解吸，解吸30min30min。解吸液供测定。若浓度。解吸液供测定。若浓度超过测定范围，用二硫化碳稀释后测定，计算时超过测定范围，用二硫化碳稀释后测定，计算时乘以稀释倍数。乘以稀释倍数。2.2.标准曲线的绘制：加标准曲线的绘制：加10ml10ml二硫化碳于比色管中，二硫化碳于比色管中，用微量注射器准确分别加入用微量注射器准确分别加入1010 l l 苯、甲苯、二甲苯、甲苯、二甲苯（在苯（在2
10、020，1 1 l l 苯、甲苯、邻二甲苯、间二甲苯、甲苯、邻二甲苯、间二甲苯、对二甲苯分别为苯、对二甲苯分别为0.8787mg0.8787mg、0.8669mg0.8669mg、0.8802mg0.8802mg、0.8642mg0.8642mg、0.8611mg0.8611mg），为标准溶），为标准溶液液4 4。再将此标准液依次。再将此标准液依次4 4倍稀释成下列标准系列。倍稀释成下列标准系列。进样进样1.01.0 l l，测定各标准管。以峰面积分别对苯、，测定各标准管。以峰面积分别对苯、甲苯及二甲苯浓度甲苯及二甲苯浓度( ( g/ml)g/ml)绘制标准曲线。绘制标准曲线。 MOE Key
11、 Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public Health管 号01234苯浓度，g/ml0.013.754.9219.7878.7甲苯浓度，g/ml0.013.654.2216.7866.9邻二甲苯浓度，g/ml0.013.855.0220.08
12、80.2对二甲苯浓度，g/ml0.013.554.0216.0864.2间二甲苯浓度，g/ml0.013.453.8215.3861.1MOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public Health3.样品测定：用测定标准系列的操作条件测
13、定样品和空白对照的解吸液；测得的样品峰面积值减去空白对照峰面积值后，由标准曲线得苯、甲苯、二甲苯的浓度(g/ml)。MOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public Health【计计计计 算算算算】1. 1. 按式（按式（1 1）将采样
14、体积换算成标准采样体积：）将采样体积换算成标准采样体积： （1 1）式中：式中： VoVo：标准采样体积（：标准采样体积（L L）；）；VtVt：采样体积（：采样体积（L L）；）；t t：采样：采样点的温度（点的温度（）；）；P P：采样点的大气压，：采样点的大气压，kPakPa。2. 2. 按式（按式（2 2）计算空气中苯、甲苯、二甲苯的浓度。）计算空气中苯、甲苯、二甲苯的浓度。 （2 2）式中：式中： C C：空气中苯、甲苯、二甲苯的浓度，：空气中苯、甲苯、二甲苯的浓度，mg/ m3mg/ m3；c1,c2c1,c2：测得前后段解吸液中苯、甲苯、二甲苯的浓度，测得前后段解吸液中苯、甲苯、
15、二甲苯的浓度， g/mlg/ml；v v：解吸液的体积，：解吸液的体积，mlml；VoVo：标准采样体积，：标准采样体积，L L；D D：解吸：解吸效率，效率，%。 MOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public HealthMOE K
16、ey Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public HealthMOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, I
17、nstitute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public HealthR.T.1（s）234溶剂2.4562.4292.4322.425苯2.722.6952.692.685甲苯3.1543.1213.123.112二甲苯13.9353.8963.8963.887二甲苯24.0193.983.983.97二甲苯34.3474.3054.3054.295MOE Key Laboratory of Environmental & H
18、ealth, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public HealthMOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine
19、, Institute of Environmental Medicine, School of Public HealthSchool of Public HealthMOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public HealthMOE
20、 Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public Health【思考题】1.如何通过标准物质定性分析？2.如果二甲苯的三个峰没有分开，如何才能得到分离效果较好的峰？3.气相色谱仪有几个部分组成？4.假定我们的样品是大气或者工厂生产车间的样本，请说明该处气体达到何种国家标准值？MOE Key Laboratory of Environmental & Health, MOE Key Laboratory of Environmental & Health, Institute of Environmental Medicine, Institute of Environmental Medicine, School of Public HealthSchool of Public Health
