It is depend on how frequently you use it, we are daily using Shimadzu equipment, 10-15 min maximum enough to establish (including purging time)

Your question doesn't make sense - you do NOT equilibrate an HPLC. You might, however, flush solvent through the system if you were changing over to a different set of immiscible solvents, for example. You DO, however, equilibrate the HPLC column. Perhaps I am being a little pedantic but these are very different processes, fulfilling different roles.

If you mean to ask how long you should equilibrate your HPLC COLUMN then the answer is going to depend on the size, or more particularly the volume of your column and the solvent flow rate. A useful rule of thumb is to equilibrate with 20 column volumes, however, I would recommend that you consult the manufacturer's literature. Many chromatography companies have background reading on their websites.

Thank you Charles! The responses posted by Simon (who now has deleted their answer) and Kolita imply they have not yet learned the fundamentals of HPLC and are offering misinformation to confuse others using RG. Please do not follow their suggestions. Equilibration times are not based on "frequency of use" ???? Your specific HPLC system configuration AND method selection will determine what an appropriate column equilibration time should be. Equilibration times are based on method details, not made-up universal values or what someone at another lab uses. While column volume, flow rate and time are the key parameters to consider in determining estimated equilibration times, the truth is that it "takes as long as it takes". Math alone will not define the time. If you do not know how to calculate this time yet, it is because you have not yet learned the basic principles needed to use the system. Please do not use the HPLC system until after you have had time to learn the basic principles of chromatography AND the layout and operation of the specific HPLC system that you have.

In the many courses we teach, I often suggest starting with one of the classic books on the topic, "Introduction to Liquid Chromatography" by Synder, Dolan et al. It is an older book, but the concepts still apply to everything we do today. While no book will teach you how to perform chromatography, good books (and good websites too) will provide you with the key concepts needed before starting any analysis (e.g. Column void volume/time, K prime, Resolution, injection solution and volume, detection settings, mobile phase choice, polarity, pH etc). If possible, please find someone with professional experience at your school to help you as chromatography takes many years to reach just a basic level of proficiency.

Dear Keila!

I would say that Charles H Hocart is right. Your question is somehow incorrect and therefore you have to specify what exactly you are going to equilibrate. You have nothing to be equilibrated until the first run of the sample was made.

Whether you meant conditioning of column you bought? If so, then I would suggest following the recommendations of the column producer. Usually, this information is outlined in the specification for a HPLC column. Take a look, please!

Hope you already solved your problem!

Yours sincerely,

Vitali