利用者:4dimp/下書き/熱分解ガスクロマトグラフ質量分析法
熱分解ガスクロマトグラフ質量分析法（ねつぶんかいガスクロマトグラフしつりょうぶんせきほう、英:Pyrolysis–gas chromatography–mass spectrometry）とは、質量分析法における1つの方法である。Py-GC/MSなどと略される。ガスクロマトグラフ質量分析計の試料導入部に熱分解装置（パイロライザー）を備えたものであり、試料は熱分解装置で瞬時に加熱され小分子へと熱分解され、ガスクロマトグラフによって分離され質量分析計にて検出される。[1]特別な前処理なしに通常のGC/MSでは分析を行うことのできない高分子化合物や異物の同定、モノマーレベルでの解析などに威力を発揮する。
原理
[編集]熱分解は不活性雰囲気下か真空下で行われる加熱することで行われる材料の分解である。試料は白金ワイヤーか、水晶でできたサンプルチューブにのせて直接導入され、一気に600-1000℃まで加熱される。
Depending on the application even higher temperatures are used. Three different heating techniques are used in actual pyrolyzers: Isothermal furnace, inductive heating (Curie Point filament), and resistive heating using platinum filaments.
Large molecules cleave at their weakest points and produce smaller, more volatile fragments. These fragments can be separated by gas chromatography. Pyrolysis GC chromatograms are typically complex because a wide range of different decomposition products is formed. The data can either be used as fingerprint to prove material identity or the GC/MS data is used to identify individual fragments to obtain structural information.
To increase the volatility of polar fragments, various methylating reagents can be added to a sample before pyrolysis.
Besides the usage of dedicated pyrolyzers, pyrolysis GC of solid and liquid samples can be performed directly inside Programmable Temperature Vaporizer (PTV) injectors that provide quick heating (up to 60°C/sec) and high maximum temperatures of 600 - 650°C. This is sufficient for many pyrolysis applications. The main advantage is that no dedicated instrument has to be purchased and pyrolysis can be performed as part of routine GC analysis. In this case quartz GC inlet liners can be used. Quantitative data can be acquired, and good results of derivatization inside the PTV injector are published as well.[2][3]
Applications
[編集]Pyrolysis gas chromatography is very useful for the identification of synthetic polymeric media, such as acrylics or alkyds, and synthetic varnishes.[4] It can also be used for environmental samples.,[5] including fossils.[6] Trace evidence scientists in forensic laboratories use Pyroylsis GC to compare and identify paint or finish found at crime scenes or victims.
References
[編集]- ^ Halket JM, Zaikin VG (2006). “Derivatization in mass spectrometry --7. On-line derivatisation/degradation”. European Journal of Mass Spectrometry 12 (1): 1–13. doi:10.1255/ejms.785. PMID 16531644.
- ^ Erwin R. Kaal, Mitsuhiro Kurano, Margit Geißler, Hans-Gerd Janssen (2008). “Hyphenation of aqueous liquid chromatography to pyrolysis-gas chromatography and mass spectrometry for the comprehensive characterization of water-soluble polymers”. Journal of Chromatography A 1186 (1-2): 222–227. doi:10.1016/j.chroma.2007.10.035.
- ^ Eckerle, P., Pursch, M., Cortes, H. J., Sun, K., Winniford, B. and Luong, J. (2008). “Determination of short-chain branching content in polyethylene by pyrolysis comprehensive multidimensional gas chromatography using low thermal mass column technology”. Journal of Separation Science (1): 3416–3422. doi:10.1002/jssc.200800218.
- ^ “National Gallery of Art Conservation: Scientific Research”. 2007年8月21日閲覧。
- ^ Janos P (2003). “Separation methods in the chemistry of humic substances”. Journal of Chromatography A 983 (1-2): 1–18. doi:10.1016/S0021-9673(02)01687-4. PMID 12568366.
- ^ Poinar HN (2002). “The genetic secrets some fossils hold”. Acc. Chem. Res. 35 (8): 676–84. doi:10.1021/ar000207x. PMID 12186573.