We are currently running our environmental Sample analysis on a HPLC/triple-Quad LC/MS MS (API 2000). I wonder whether we may just move the method without major modifications (except for column dimensions and particle size for UHPLC separation) or whether some specific adjustments are advised?
http://www.sigmaaldrich.com/analytical-chromatography/hplc/method-transfer-calculator.html This calculator may help - you will probably need to adjust the mobile phase flow rate, and depending if your aim is to significantly decrease the run time, you may need to look at modifying (increasing) the data acquisition rate as well, or you can lose peak shape integrity. If your column dimensions are significantly different, then sample load will also need to be changed. I know some instruments have built in calculators that can automatically adjust these parameters, simply by changing the mode from HPLC to UHPLC.
As I understand you want to use Exactive - only full scan MS in high resolution and in negative mode. There is a limitation which comes from function of Orbitrap - better resolution means longer time in analyser so - with resolution which is reasonable for environmental samples (70000 FWHM) you can have a trouble with scaning frequency - number of points per peak. I use for this analysis QExactive and MS (0,7 FWHM)/PS HRMS (17500 FWHM) because the selectivity even at 70000 was not enough good in real samples - fish extracts. I have to use chromatography at 3 µm particle size (50mmx2,1 mm ID) to get good sampling frequency in chromatograms. Peak width 0,2-0,3 min. is O.K. for transer the method. If you have peak width 0,1 min. and lower you will probably have some troubles. You have to check in Exactive manuals (or ask service support) how long time in ms will take full scan at your suggested resolution for your m/z range and calculate theoretical sampling frequency. All sulphonates and carboxylates could be done in negative mode. If you want ot add polarity switching it will be much slower - on border for conventional chromatogrphy.
Hi Roland, I would assume you can keep you HPLC methd. the MS method you need to redo from scratch the ion source is quite different on the 2000 you probaby run MRM, which you would not do on the orbi. the collision energies are different for 2000 vs the thermo machines as sciex is using nitrogen and on the thermo machine you are probably using argon as collision gas.... just a few ideas ;-) kind regards
kai
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