A Thermogravimetry−Capillary Gas Chromatography/Mass Spectrometry Interface

Abstract

An interface and gas chromatograph oven are described that couple a thermogravimetric analyzer with a mass spectrometer and permit multiple capillary gas chromatographic separations of volatile thermal decomposition products generated during a single thermogravimetric analysis. Examples of the use of this apparatus for identifying the volatile products generated during poly(vinyl butyral) thermal decomposition in the presence of γ-alumina and catalytic cracking of poly(styrene) and poly(ethylene) are described. TG-GC/MS analyses employing isothermal, temperature programmed, and subambient temperature ramp gas chromatography separations are described. The apparatus permits repetitive temperature-programmed capillary gas chromatographic analyses of thermogravimetric effluent containing more than 25 constituents in 3-min intervals.

Estimating Realistic Confidence Intervals for the Activation Energy Determined from Thermoanalytical Measurements

“…Thermoanalytical methods find extensive application in analysis of various materials. , The field of analytical applications constantly expands by accommodating new technical solutions. − In particular, thermal methods of analysis are effectively used to study the kinetics of chemical reactions. ,, These studies usually have two major objectives, namely, probing the reaction mechanisms and parametrizing the reaction rates. Of these two objectives, the latter has the foremost practical importance, because kinetic parameters are routinely used for predicting thermal stability of materials.…”

Volatile Mixture Analysis by Repetitive Injection Fast Gas Chromatography/Mass Spectrometry

“…For those instances when it is desirable to monitor multiple substances, methods that can simultaneously detect and quantify volatile mixture components are needed. Gas chromatography is a method that is commonly employed to separate and quantify multiple gas phase mixture components. , The advantages of using gas chromatography for separation of the volatile mixtures generated during thermal analyses have been known for at least forty years. − Additional information regarding evolved gas mixture components can be obtained by combining gas chromatography with mass spectrometry detection (GC/MS). − By using isothermal gas chromatography separations, GC/MS evolved gas sampling intervals of 1−2 min have been reported. ,− Somewhat longer sampling intervals (3−5 min) have been reported when temperature-programmed GC separations are required. ,, The assay cycle time required for repetitive GC/MS analyses depends on the length of time required for chromatographic separation and, when temperature programmed separations are employed, the time required to cool the chromatographic column back to the ramp starting temperature.…”

“…[3][4][5] Additional information regarding evolved gas mixture components can be obtained by combining gas chromatography with mass spectrometry detection (GC/MS). [6][7][8][9][10][11][12][13][14][15][16][17][18] By using isothermal gas chromatography separations, GC/MS evolved gas sampling intervals of 1-2 min have been reported. 11,[13][14][15] Somewhat longer sampling intervals (3-5 min) have been reported when temperature-programmed GC separations are required.…”

“…11,[13][14][15] Somewhat longer sampling intervals (3-5 min) have been reported when temperature-programmed GC separations are required. 12,17,18 The assay cycle time required for repetitive GC/MS analyses depends on the length of time required for chromatographic separation and, when temperature programmed separations are employed, the time required to cool the chromatographic column back to the ramp starting temperature.…”

Σύνθεση Θερμοζυγού - Αερίου Χρωματογράφου- Φασματόμετρου Μάζας Για Την Ανάλυση Αερίων Εκλυομένων Κατά Τη Θερμική Κατεργασία Ενώσεων Και Υλικών

“…Η χρήση όμως μιας μεθόδου θερμικής καταπόνησης με μικρό ρυθμό θέρμανσης (μικροφσύρνσς, θερμοζυγός κτλ), οδηγεί σε μεγάλες διάρκειες εισαγωγής δείγματος στη χρωματογραφική στήλη και επομένως καθιστά αδύνατο τον χρωματογραφικό διαχωρισμό λόγω επικαλύψεων των κορυφών. Στην περίπτωση αυτή επιβάλλεται η χρήση σχετικά πολύπλοκων τρόπων διασύνδεσης των δύο σταδίων που επιτρέπουν την περιοδική δειγματοληψία των αερίων με παλμούς μικρής διάρκειας (11,12,13,14,15,16,17).…”