Question about internal standard and its dynamic range

[jusuom]

I would need help in this:

http://www.sepsci.com/chromforum/viewtopic.php?t=7031

[jusuom]

Any ideas/remarks from anybody?

[Peter Apps]

Intersting points.

You are right about the response for the internal standard needing to be within the dynamic range of the analysis.

The slope and intercepts of the analyte and internal standard calibrations do not need to be similar. The IS does need to be closely similar to the analyte in its behaviour during sample preparation (especially), separation and detection. All else being equal isotope labelled analogues of the analyte are the best internal standards.

Peter