Mass selective detector coupled to gas chromatography (GC-MSD) and to thermogravimetry (TG-MSD) Dr. Mihai Brebu 1. Gas chromatography (GC) 2. Thermogravimetry (TG) 3. Mass selective detector (MSD) 4. Gas chromatography - Mass selective detector (GC-MSD) Institutul ‘Petru Poni’ Iasi, aprilie 2009
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Mass selective detector coupled to gas chromatography (GC-MSD) and to thermogravimetry (TG-MSD)
Institutul ‘Petru Poni’ Iasi, aprilie 2009. Mass selective detector coupled to gas chromatography (GC-MSD) and to thermogravimetry (TG-MSD) Dr. Mihai Brebu 1. Gas chromatography (GC) 2. Thermogravimetry (TG) 3. Mass selective detector (MSD) - PowerPoint PPT Presentation
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Mass selective detector coupled to gas chromatography (GC-MSD)
and to thermogravimetry (TG-MSD)
Dr. Mihai Brebu
1. Gas chromatography (GC)
2. Thermogravimetry (TG)
3. Mass selective detector (MSD)
4. Gas chromatography - Mass selective detector (GC-MSD)
5. Thermogravimetry - Mass selective detector (TG-MSD)
Institutul ‘Petru Poni’ Iasi, aprilie 2009
1. Gas chromatography (GC) Institutul ‘Petru Poni’ Iasi, aprilie 2009
Gas chromatography: analysis technique for qualit./quantit. determination of compounds in mixtures
Compounds separation by selective adsorption/desorption affected by temperature, gas flow (for a given column)
Detection of compounds based on specific properties
Recording/analysis/display of signal
Vaporisation, mixing with carrier gas, injection in the column
Column
Detector
Recorder
Inlet
retention time (rt) depends on: characteristics of the column (length, diameter, filling) polarity of compounds (rt izooctan < octena < octan) molecular weight of compounds (rt heptan < octan < nonan) temperature program (rt decreases at high temperatures) carrier gas flow (rt decreases at high flows)
qualitative analysis: - from retention times - from MSDquantitative analysis: - from peak area
1. Gas chromatography (GC) Institutul ‘Petru Poni’ Iasi, aprilie 2009
good balance between short analysis time and good separation of compounds
2. Thermogravimetry (TG) Institutul ‘Petru Poni’ Iasi, aprilie 2009
Thermogravimetry: analysis technique for thermal processes involving mass loss (thermal degradation)
thermal behaviour - described by: temperature for onset of the degradation step temperature for maximum rate of degradation temperature for end of the degradation step final mass loss of degradation step
thermal behaviour - affected by: temperature program (heating rate) atmosphere (air, inert gas) sample mass
Polyurethane
2. Thermogravimetry (TG) Institutul ‘Petru Poni’ Iasi, aprilie 2009
5. Thermogravimetry - mass selective detector (TG-MSD) Institutul ‘Petru Poni’ Iasi, aprilie 2009
PEG
5. Thermogravimetry - mass selective detector (TG-MSD) Institutul ‘Petru Poni’ Iasi, aprilie 2009
PEG
5. Thermogravimetry - mass selective detector (TG-MSD) Institutul ‘Petru Poni’ Iasi, aprilie 2009
PU
5. Thermogravimetry - mass selective detector (TG-MSD) Institutul ‘Petru Poni’ Iasi, aprilie 2009
-FeOOH -Fe2O3 • H2O Fe3O4
m/z 17 vs m/z 18 - ct.
changes in composition and structure of -FeOOH during catalytic degradation of ABS
5. Thermogravimetry - mass selective detector (TG-MSD) Institutul ‘Petru Poni’ Iasi, aprilie 2009
reaction of 4-phenylbutironitrile over -FeOOH catalysts and its derivatives
NH3:14,15,16, 17/18
reduction of catalyst by organic compounds
alkyls: 27,28,29,14,15
toluene, ethylbenzene: 91
aliphatic nitriles: 41,14,15,16,28,29
Institutul ‘Petru Poni’ Iasi, aprilie 2009
Acknowledgements:
- Dr. Dan Rosu - Dr. Vasile Cornelia
- Dr. Nita Tudorache - Prof. Yusaku Sakata
Conclusions:
- MSD is a powerful detector for qualitative identification of compounds leaving a GC column or a TG furnace
- identification is facile in GC-MSD if compounds are well separated by GC and their structure is included in databases
- careful interpretation of mass spectra is need if compounds are not well separated by GC and their structure is not included in databases
- careful analysis of various mass signals is need for TG-MSD data since compounds are not separated and the mass signals might represent a sum of contributions from fragmentation of different compounds