Chromatography Forum

If I analyze for multiple analytes, do all analytes need to be present in all solutions? Can I calibrate 1 analyte using one set of calibration standards and then calibrate a second analyte using a separate set of calibration standards? The assumption here, is that both analytes are quantitated in a single chromatogram with adequate resolution. A source would also be helpful!

You can process data where you've got two independent sets of calibration standards containing different calibrants, but it's a real inconvenience and there is no benefit to doing so; it's the sort of thing you'll do if you're running someone else's samples and they've given you the standards ready-prepared but not all in the same vials, or if you realise half way through the batch that you want to add an analyte, so you stick an extra calibration series on the end (hey, bracketing's for wimps...)

The easiest way to do it is just to set up a processing method for standard set A, fill in all the details in your sequence, and process it, then set up a processing method for standard set B, modify your sequence, and process it again. So basically it's double the work. I don't believe there are any specific issues about the validity of this - both halves of the process are completely normal analyses unaffected by the other half.

But of course you're quite right about resolution. You can't do this just because standards A and B run on top of each other and aren't properly resolved, because then they won't be properly resolved in the samples either.