Vielitzer Straße Selb GERMANY Tel.: Fax: Linseis Inc. 20 Washington Road P.O.Box 666 Princeton-Jct. NJ Tel.:(609) Fax:(609)

The Company Since 1957 Linseis Corporation delivers outstanding service, know how and leading innovative products in the field of thermal analysis and thermal physical properties. We are driven by innovation and customer satisfaction. Customer orientation, innovation, flexibility and last but not least highest quality are what Linseis stands for from the very beginning. Thanks to these fundamentals our company enjoys an exceptional reputation among the leading scientific and industrial companies. Claus Linseis Managing Director

INTRODUCTION TO EVOLVED GAS ANALYSIS

Thermogravimetric analysis (TGA) provides information about: weight changes as a function of temperature or time decomposition temperature  b ut it cannot identify the gaseous products evolved ! Why EGA ? Temperature Weight 0 m1m1 m2m2 T1T1 T2T2

Why EGA ? Combination of TGA with a gas analyzer provides qualitative information about the chemical nature of evolved gases  results can be correlated directly with the measured weight losses  overall picture over what is going on with the sample Possible gas analyzers: - Mass spectrometry (MS) - Infrared spectroscopy (FTIR) - Gas chromatography (GC) - Inductive coupled plasma (ICP) - GC/MS

TGA-MS TGA-FTIR EGA System Setup TG Analyzer BalanceFurnace Gas Analyzer QuadrupolePump Purge gas Purge gas + products Capillary Heater TG Analyzer BalanceFurnace Gas Analyzer Interferometer Gas Cell Purge gas Purge gas + products Transfer Line Heater

MS: measuring principle MS: Introduction

Fragmentation "A mass spectrometrist is someone, who figures out what something is, by smashing it with a hammer and looking at the pieces" MS: Introduction

Available for mass ranges of 100, 200 and 300 amu Scan Analog: continuous scanning of certain mass range(s) MID: selected m/e’s are measured continuously Scan Bargraph: certain masses are continuously scanned. MS: Introduction Balzer‘s „Thermostar“

Advantages of MS Coupling Easy detection of inert and inorganic gasses Real-time detection of temp. dependent gas evolution Very low detection limits (ppb) Vacuum TGA applications OK Disadvantages Hydrocarbon analysis limited MS advantages / disadvantages

FTIR: Basic principle

FTIR: What you get What do you get from an FTIR-measurement? Spectra: Absorbance or transmittance as a function of the wavenumber Gram-Schmitt curve: Integral of the spectra over the wavenumber as a function of time (similar to DTG, contains no chemically specific information) Chemigrams: Integral of the spectra in selected wavelength-bands as a function of time (sometimes also called „functional group profile“) General procedure Calculate DTG curve Check the spectra at the DTG-peak maxima and compare it with reference spectra (database) Determine characteristic wavelength bands for chemigrams

FTIR: What you get Evolved Gas Profile (spectrum) Functional Group Profile (chemigram) cm -1 m/m 0 ; [-] Abs. Temperature 0TG DTG 1 Time cm -1 1

Interpretation of spectra: FTIR

FTIR advantages / disadvantages Advantages of FTIR Coupling Easy detection of hydrocarbons Real-time detection of temp. dependent gas evolution Disadvantages No detection of inert gasses Detection of inorganic gasses limited Detection affected by water vapor

A known amount of gas is injected into the sample gas stream and the registered signal of the resulting pulse is integrated. The proportionality between the injected gas quantity and the peak area found for the TG-MS and TG-FTIR in a broad range of temperatures and gas quantities. The injected gas can be selected according to the expected evolving gases, so that an on-line calibration is possible for many of the volatilities. Linseis Gas Pulse

Decomposition of CaC 2 O 4 under Argon atmosphere TG/DTA – MS-coupling

Composition of cement raw materials QMS This application is a clear indicator of how powerful results a simultaneous thermal analyzer coupled with a Mass Spectrometer can deliver. The two mass-loss steps between approx. 250°C and 450°C are due to the combustion of organic components. This is indicated by both the exothermal DSC signal and the detected MS signal for water and CO2. Furthermore several dehydration steps below 600°C can be seen. The decomposition of CaCO3 between 600°C and 850°C as well as the decomposition of CaSO4 between 1200°C and 1350°C can clearly be detected by means of the MS signals. Moreover, some not oxidized organic decomposition products are visible around 336°C by the MS signal.

TGA – FTIR Portland Cement

TGA – FTIR / Ti Powder