Chromatography Forum

I work with silica particles that are coated with ethyleneglycol moieties. I silanized these silica in our lab. I noticed that for a new column there is a 'conditioning' period where it took several injections for the sample peak to achieve a constant height. Is this normal? if yes, why? I also read a paper that mentioned such behavior on their ethyleneglycol coated silica column, Im just wondering why.

Thanks

That's not an unusual problem in chromatography of proteins. Presumably there are some residual active sites (despite the silanization!) that are "eating" some of your sample.