L2 - Methods for the characterization of organic matter Part III and IV: Analysis and Harvesting compounds and non-extractable material Flashcards
What are the main steps of GC-MS analysis?
Injection
Separation
Detection
Identification/Quantification
What is the purpose of separation in GC-MS?
To separate compounds based on their physical and chemical properties before detection.
What types of columns are used in GC-MS separation?
- Capillary columns with different coatings.
- Most common: HP-5 (5% phenyl column).
What are the two types of temperature control in GC-MS?
Isothermal (constant temperature)
Temperature program (controlled heating steps)
What parameters are involved in a temperature program?
Initial temperature
Initial time
Temperature rate
Final temperature
Final time
Why is choosing the right column and temperature program important?
For optimal separation of compounds in a sample.
What are the different types of detectors used in GC-MS?
Thermal Conductivity Detector (TCD)
Flame Ionization Detector (FID)
Electron Capture Detector (ECD)
Flame Photometric Detector (FPD)
Atomic Emission Detector (AED)
Infrared Detector (IR)
Mass Spectrometer (MS)
What is mass spectrometry (MS)?
Separation of matter based on atomic and molecular mass
How does mass spectrometry work?
Ionized molecules are separated based on their mass-to-charge ratio (m/z)
What information can mass spectrometry provide?
Quantification of atoms and molecules
Chemical/structural information
Isotopic composition
What are the key features of a mass spectrum?
Molecular ion (M⁺)
Base peak (B⁺)
Fragment ions
Where can you see practical examples of mass spectra interpretation?
In practical lab sessions
Which lipids are not suitable for GC analysis?
Wax esters
Steryl esters
Triacylglycerols
Phospholipids
How are compounds separated using GC?
On a molecular/compound level.
What are the limitations of GC for compound harvesting?
Time-consuming
Expensive
Requires large sample amounts
What tool can help collect fractions in GC?
Preparative fraction collector
How does GC compare to other injection techniques?
More sample can be injected in a single run than with standard GC.
What methods are used for analyzing non-extractable materials?
Chemical degradation techniques, including:
Saponification
Ruthenium tetroxide degradation
Raney nickel desulfurization
Cupric oxide oxidation
Thermal degradation
What is pyrolysis?
The chemical decomposition of organic materials by heating in the absence of oxygen
What is Py-GCMS used for?
Analyzing non-GC amenable macromolecular organic matter (OM) such as lignin and cellulose
What is the final step of Py-GCMS?
Reconstruction of chemical composition from the analysis.
gc ms
1️⃣ Gas Chromatography (GC) – Separates compounds based on their volatility and interaction with the column.
2️⃣ Mass Spectrometry (MS) – Identifies and quantifies compounds by analyzing their mass-to-charge ratio (m/z)
