Chromatography Forum

Greeting all,

Wonder if anyone knows how to set the tune parameters in Agilent 5973 MSD such that it behaves like an FID, i.e. the entire mass range have same response. Thanks.

Hubert

I am not sure I understand what you want to do. It sounds like you want to detune the MS to pass all ions to the detector?

You can get a total ion current result by acquiring in scan mode over a wide range and using the TIC. And, you can verify the relative sensitivity as a function of mass by looking at the tune report. If you turn the quadropole to be nothign more than an ion guide, how will you ensure that the efficiency of transmission, one mass relative to another, does not change over time? Changing transmission efficiency will reslt in varying reponse factors between molecules.

While you might be able to acquire the total ion current this way, the response factor will not be the same as for the FID.

In principle, it is impossible for that to be done. The FID responses are not related to the number of ions produced in the MS inlet for analytes. This simply means, like Don said, that it is not possible to correlate FID with TIC even if you use the quadrupole simply as an ion guide. Extreme case, for example, is water for which you will see no FID response, but will see response from MS.

chhubert,

I don't know if this is the same thing as what you are asking, but I do know of someone who is using their MS to measure total gasoline (GRO) in addition to BTEX in environmental samples. Not exactly sure how they are doing it but if this what you are interested in, I will ask and he might answer.

Best regards.