FPP to SPP conversion - equations and calculator

[lanon2]

Hi All,

I spent the last hour researching the methodology for converting from FPP to SPP columns and each reference seems to have their own way of performing the calculation and with drastically different results. Does anyone have a reliable, easy to understand resource for this conversion? A calculator would be great, but I also want to understand exactly what calculations are being performed.

Even the phenomenex calculator for FPP to SPP conversion has me scratching my head.
https://www.phenomenex.com/Tools/Kinete ... 2d710e510a
The phenomenex calculator is telling me I should use the same injection volume after reducing the column length from 150 to 75 mm. How can that be? And, I have no idea how they are calculating the new flow rate!

Other references suggest I should calculate the new injection volume and the new flowrate in the same way as with FPP conversions (FPP method to FPP method) and the only change for FPP to SPP conversion would be the equation used for calculation of the new gradient time(s).

Not sure who is right?!

Looking for conversions for both isocratic and gradient methods.

Thanks!

[tom jupille]

Changing the physical parameters of a separation (particle size / column size / flow) is straightforward. There are a number of calculators available that will do the job (including one on our website at https://www.lcresources.com/sandbox/UPLC-HPLC.xls ).

Changing the stationary phase chemistry (since superficially porous and totally porous packings have different phase ratios, that's what you're doing) is a different story. In my opinion there is no consistent way to do it without experimental data; in essence you must (at least partially) redevelop the method. Chromatography modeling programs like DryLab or ChromSword can help in that regard, but they do require experimental input.