Chromatography Forum

Hello. I´m analysing fatty acid methyl ester by a GC-FID instrument. In my samples i don´t have enough sensibility to distinguish this peaks over another.
I´ve heard that there is a method (i don´t know it name) with you can improve the sensibility of your peaks by means of add a known amount of your analite of interest.Does anyone know anything about this?

Thanks

Hello. I´m analysing fatty acid methyl ester by a GC-FID instrument. In my samples i don´t have enough sensibility to distinguish this peaks over another.
I´ve heard that there is a method (i don´t know it name) with you can improve the sensibility of your peaks by means of add a known amount of your analite of interest.Does anyone know anything about this?

Thanks

Not that way. You won't improve sensitivity of FID by adding FAME to your sample. Instead your sample should be more concentrated allowing you to detect FAMES of interest.

I suspect you need to improve resolution of your GC method (right column, proper carrier flow, proper temp. program).

More details neccessary.

From what I gather, you're looking either for better resolution (separation between peaks) or greater sensitivity (greater height on peaks). If the former, then there could be two ways to approach it, depending on details you might need to give us:

1) You have the wrong type of column installed
2) You need to work on the acquisition method (temp. program, pneumatics, etc)

If the latter, you could approach it a few ways:

1) More concentrated sample
2) Lower split ratio
3) Splitless injection

Adding more of an analyte you're looking for is going to give you fabricated results--you'll end up seeing what you put in, right? There are times when you want to dope samples to see certain peaks change, but I'm guessing this isn't one of those times.

You need to give more details:

Column characteristics/type
Flows
Temp program
a sample chromatogram

Anything you can give to help us help you.

Best of luck!