GC

Question 1

What is the difference is between gas-solid and gas-liquid gas chromatograpy

Answer 1

The Stationary Phase:

For gas-solid: a solid stationary phase is used

For gas-liquid: a liquid stationray phase is used.

Question 2

What is an internal Standard and what is the purpose of it.

Answer 2

An internal standard is a substance that is added to all samples . These are used to determine if there is any sample loss during the sample preparation step.

Question 3

How are quantitiative and qualitative infomation obatined from the gas chromotogram?

Answer 3

Quantitative infomation can found from the areas under the curuve.
Qualtitive information can be found from the rention times of the certin speices

Question 4

In GC what is the difference between retention time and retention index

Answer 4

Retention time is the time it takes to reach the detector.

The retention index is the time different carbon based compounds take to reach the detectors

Question 5

What is the main cause of band broading in gas chromatography using a capillary column?

Answer 5

In a capillary column there is no A term since there is no packing.

Also the Cmu term is due to a small radius.

Hence longtitdunal diffiusion is the main cause of band broadening

Question 7

Name 6 different detectors in GC

Answer 7

Nitrogen-Phosphours
Flame ionization detector
Mass-spec
Electron-capture detector
Sulfulr Chemiluinence device