Chromatography Forum

Simple question for you guys: is there a quantitative parameter that is used to describe the polarity of a solvent in the context of HPLC? I was thinking that a simple dipole moment calculation would do the job, but for HPLC it must be more complex. For HPLC the miscibility of solvents is also relevant, and the magnitude of a dipole moment does not reflect this molecular characteristic.

Is there a parameter that takes both these qualities into account? I am not asking for an explanation, a one sentence answer will suffice as I can do the digging

Thanks,

Luke

Hi

Eluent strenght (based on solubility on silica gel) is one that comes to mind, but there might be others.

Some vendors of HPLC solvents have lists with various parameters.

Roughly speaking (and grossly oversimplifying!), the sum of hydrogen-bonding acidity, hydrogen-bonding basicity, and dipole moment correlate well with what we intuitively think of as "polarity". If you can get hold of a copy of Snyder, Kirkland, and Dolan's "Introduction to Modern Liquid Chromatography" (here's a link to it on Amazon: http://tinyurl.com/bltfok8 ) look around page 33-34 for a more detailed discussion.

Thanks for the tips!!!

Luke