[Rowanstudent1989]

What relative response should I be expecting on FID for benzene, THF, benzyl alcohol, hexane, and aniline?

[chiralic]

Hello Rowanstudent1989:

What is your standard compound? What is your stationary phase?

You must read this concept:
Relative Retention (r)
The ratio of the adjusted or net retention volume (time) or retention factor of a component relative to that of a standard, obtained under identical conditions:

r = V_Ri'/V_R(st)' = V_Ni /V_N(st) = t_Ri'/t_R(st)' = k_i /k_st

Depending on the relative position of the peak corresponding to the standard compound in the chromatogram, the value of r may be smaller, larger or identical to unity.

Also you can search on internet the following term: Relative Retention Indices

Best regards,

Chiralic

[DrCMS]

Hello Rowanstudent1989:

What is your standard compound? What is your stationary phase?

You must read this concept:
Relative Retention (r)
The ratio of the adjusted or net retention volume (time) or retention factor of a component relative to that of a standard, obtained under identical conditions:

r = V_Ri'/V_R(st)' = V_Ni /V_N(st) = t_Ri'/t_R(st)' = k_i /k_st

Depending on the relative position of the peak corresponding to the standard compound in the chromatogram, the value of r may be smaller, larger or identical to unity.

Also you can search on internet the following term: Relative Retention Indices

Best regards,

Chiralic

Read the question before you answer it. 

Rowanstudent1989 asked about the relative response factors for these compounds in an FID detector not about retention times.

In answer to that question I'm not sure.  I'd expect benzene and hexane to be similar with the the others being lower in the order aniline> benzyl alcohol >THF.

[Rivet]

I agree.  The FID basically counts carbons.

[redskytonight820]

The larger the organic molecule, the more of a relative response you will get.

For example, Toluene will get more of a response from FID than Benzene.

[chiralic]

Dear Dr.CMS...I read in wrong way...

The FID signal is proporcional to the number of carbon atoms in hydrocarbon molecules, and the presence of a heteroatom in the molecule causes a decrease in the signal of the FID.

The signal-deacreasing effect of heteroatom and functional groups are expressed by the EFFECTIVE CARBON-ATOM NUMER.

Regards

Chiralic