Question

You carry out a gas chromatography experiment and find that the k' for methane is 4.46 and pentane is 111.8. What will be the k' value for propane?

Answer 1

k is the retention factor

the retention factor is given

k'A = t R - tM / tM

where

Retention time (Tr)

The time between sample injection and an analyte peak reaching a detector at the end of the column is termed the . NOTE that each of the analytes in a sample will have a different retention time.

Mobile Phase time (Tm)

The time taken for the mobile phase to pass through the column is called tM. Which is a STANDARD since it is our mobile phase

For:

methane --> 1 carbon, K = 4.46

propane --> 3 carbon, K = ?

pentane --> 5 carbon, K = 111,8

then

calculate slope

m = (111.8-4.46)/(5-1) = 26.835

For the point of propane

K - 4.46 = 26.835(5-3)

k = 58.13 of propane

which makes sesnse since it must be between metahne - pentane