White Robert L
Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA.
Anal Chem. 2008 Dec 15;80(24):9812-6. doi: 10.1021/ac801757w.
An apparatus designed for repetitive sampling and characterization of evolved gas mixtures generated during thermal analysis is described. The apparatus combines fast temperature ramp gas chromatography separations with mass spectrometric detection to selectively monitor volatile mixture component concentration changes as a function of sample temperature. The apparatus was tested by using it to repetitively sample and analyze the volatile products generated when poly(styrene) was catalytically cracked by an HY zeolite solid acid catalyst by heating the polymer/catalyst mixture in an inert helium atmosphere. Eleven mixture components contained in the gas stream were separated and detected at 90-s intervals when the polymer/catalyst sample was heated from 200 to 400 degrees C. Mass spectral extracted ion chromatograms were employed to generate species-specific evolution temperature profiles, which provided insight into thermal reaction mechanisms.
描述了一种用于对热分析过程中产生的逸出气体混合物进行重复采样和表征的装置。该装置将快速升温气相色谱分离与质谱检测相结合，以选择性地监测挥发性混合物成分浓度随样品温度的变化。通过在惰性氦气氛中加热聚合物/催化剂混合物，利用该装置对聚（苯乙烯）被HY沸石固体酸催化剂催化裂解时产生的挥发性产物进行重复采样和分析，对该装置进行了测试。当聚合物/催化剂样品从200℃加热到400℃时，以90秒的间隔分离并检测气流中所含的11种混合物成分。采用质谱提取离子色谱图生成物种特异性的逸出温度曲线，从而深入了解热反应机理。
