空气中苯、甲苯和二甲苯的测定.ppt

《空气中苯、甲苯和二甲苯的测定.ppt》由会员分享，可在线阅读，更多相关《空气中苯、甲苯和二甲苯的测定.ppt（20页珍藏版）》请在得力文库 - 分享文档赚钱的网站上搜索。

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,【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 En

2、vironmental&Health,MOE Key Laboratory of Environmental&Health,Institute of Environmental Medicine,Institute of Environmental Medicine,【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，以保留时间定性，峰面积定量。MOE Key Laboratory of Environmental&Health,MOE Key Laboratory of Environmental&Health,Institute of E

3、nvironmental Medicine,Institute of Environmental Medicine,【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0.1-1.5L/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&He

4、alth,Institute of Environmental Medicine,Institute of Environmental Medicine,MOE Key Laboratory of Environmental&Health,MOE Key Laboratory of Environmental&Health,Institute of Environmental Medicine,Institute of Environmental Medicine,MOE Key Laboratory of Environmental&Health,MOE Key Laboratory of

5、Environmental&Health,Institute of Environmental Medicine,Institute of Environmental Medicine,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 Key Laboratory of Environmental&Health

6、,Institute of Environmental Medicine,Institute of Environmental Medicine,MOE Key Laboratory of Environmental&Health,MOE Key Laboratory of Environmental&Health,Institute of Environmental Medicine,Institute of Environmental Medicine,MOE Key Laboratory of Environmental&Health,MOE Key Laboratory of Envi

7、ronmental&Health,Institute of Environmental Medicine,Institute of Environmental Medicine,【分析步骤】【分析步骤】1.1.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

8、。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2020，1 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

9、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 Laboratory of Environmental&Health,MOE Key Laboratory of Environmental&Health,Institute of Environmental Medicine,Institute of Environmental Medicine,管管 号号0 01 12 23 34 4苯苯浓浓度，度，g/mlg/ml0.00.013.713

10、.754.954.9219.7219.7878.7878.7甲苯甲苯浓浓度，度，g/mlg/ml0.00.013.613.654.254.2216.7216.7866.9866.9邻邻二甲苯二甲苯浓浓度，度，g/mlg/ml0.00.013.813.855.055.0220.0220.0880.2880.2对对二甲苯二甲苯浓浓度，度，g/mlg/ml0.00.013.513.554.054.0216.0216.0864.2864.2间间二甲苯二甲苯浓浓度，度，g/mlg/ml0.00.013.413.453.853.8215.3215.3861.1861.1MOE Key Laboratory

11、 of Environmental&Health,MOE Key Laboratory of Environmental&Health,Institute of Environmental Medicine,Institute of Environmental Medicine,3.样品测定：用测定标准系列的操作条件测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&Hea

12、lth,Institute of Environmental Medicine,Institute of Environmental Medicine,【计【计【计【计 算】算】算】算】1.1.按式（按式（1 1）将采样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：Vo Vo：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。

13、（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、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 Med

14、icine,Institute of Environmental Medicine,MOE Key Laboratory of Environmental&Health,MOE Key Laboratory of Environmental&Health,Institute of Environmental Medicine,Institute of Environmental Medicine,MOE Key Laboratory of Environmental&Health,MOE Key Laboratory of Environmental&Health,Institute of E

15、nvironmental Medicine,Institute of Environmental Medicine,R.T.1R.T.1（s s）2 23 34 4溶溶剂剂2.4562.4562.4292.4292.4322.4322.4252.425苯苯2.722.722.6952.6952.692.692.6852.685甲苯甲苯3.1543.1543.1213.1213.123.123.1123.112二甲苯二甲苯1 13.9353.9353.8963.8963.8963.8963.8873.887二甲苯二甲苯2 24.0194.0193.983.983.983.983.973.97二甲

16、苯二甲苯3 34.3474.3474.3054.3054.3054.3054.2954.295MOE Key Laboratory of Environmental&Health,MOE Key Laboratory of Environmental&Health,Institute of Environmental Medicine,Institute of Environmental Medicine,MOE Key Laboratory of Environmental&Health,MOE Key Laboratory of Environmental&Health,Institute

17、 of Environmental Medicine,Institute of Environmental Medicine,MOE Key Laboratory of Environmental&Health,MOE Key Laboratory of Environmental&Health,Institute of Environmental Medicine,Institute of Environmental Medicine,MOE Key Laboratory of Environmental&Health,MOE Key Laboratory of Environmental&

18、Health,Institute of Environmental Medicine,Institute of Environmental Medicine,【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,