Gas Chromatography Flashcards
• Technique using analytical chemistry for separating and analyzing compounds in a complex mixtures
• it relies on the principle of differential partitioning of sample components between stationary phase and a mobile phase
• it has high sensitivity selectivity and efficiency making it an indispensable tool for qualitative and quantitative analysis of organic compounds
Gas chromatography (GC)
Gas chromatography relies on the principle of ___ ___ of sample components between a __ phase and a ___ phase
Differential partitioning
Stationary phase and mobile phase
2 phases of GC
Mobile phase
Stationary phase
• This is an inert gas typically helium or nitrogen that continuously flows through the system.
• it acts like moving platform carrying the vaporized sample components through the column.
Mobile phase (Carrier gas)
• This is a thin layer of high boiling liquid film coating the inner walls of a long, narrow column.
• it interacts with a sample components as they travel through the column
Stationary phase
Compounds have different affinities for the __ phase compared to the ___ phase
Stationary
Mobile
The sample is vaporized and carried by a gas through a ___.
Column
Inside the column the sample interacts differently with the ___ ___ causing some compounds to move ___ ( longer retention times) while others move ___
Stationary phase
Slower
Faster
The strength of this interaction in column is described by a value called the ?
distribution constant (Kc)
It represents the equilibrium between a compound in the stationary phase and the mobile phase
Distribution constant (Kc)
Compounds with ___ interactions with the stationary phase take longer to ___ (remove by washing with a solvent, especially in chromatography) from the column
Stronger
Elute
The equilibrium between the concentration of a compound in the stationary phase and the mobile phase is described by an equilibrium constant known as the ?
distribution constant or partition coefficient (Kc)
That distribution constant or partition coefficient (Kc) determines the ____ of compounds through the column and thus enables the chromatographic ____
Movement
Separation
_____ in the chemical nature of the stationary phase influences the distribution of ___
Temperature
Constant
___ phase interacts with the sample molecules differently causing separation based on ____ properties
Stationary
molecular
Mobile phase ___ the sample through the column. its flow rate affects separation efficiency.
Carries
They do not react with the sample components ensuring that the separation process is not affected by chemical interactions with the mobile phase.
Mobile phase
• it is where the sample is introduced into the system.
• It vaporizes the sample and injects it into the column.
Injector