Chromatography Forum

hi
in our labs, we developp new methods in HPLC. Thera are some softwares for the optimisation on the market: drylab, chromsword, osiris.
which is the best
in those softwares, to start the calculs, we need to enter the dead volume of the column and the gradient delay. does anybody have a simple method to calculate those two parameters?
- we work with C18 columns - the mobil phase is generally water-acn or buffer-acn

pierre

Pierre,

There is an article in LC.GC vol. 21, #12 pp.1124-1133, Dec. 2003 that covers this in detail. The web address is

http://www.lcgcmag.com/lcgc/article/art ... p?id=78758

Good luck!

The column dead volume can be estimated with an accuracy that is sufficient for your purposes by using 2/3 of the column volume.

Unfortunately, there is no way to estimate the gradient delay volume of your instrument. You need to measure it.

The on-line help file that comes with the DryLab evaluation version has a procedure for measuring gradient delay volume ("dwell volume"). You can download the evaluation version of the DryLab program from Rheodyne's web site (the link is in the "Sponsored by" box at the top of the screen).