Reverse phase HPLC and end-capping

[joho]

Am still revising but have confused myself somewhat over whether the above are the same thing or two different things.

 

In my notes I have:

normal phase silica gel with Si-O-SiOC18H37 groups and SiOH active sites for interaction with analytes and called that ODS1.

 

reverse phase HPLC as being chemically modified and having Si-OSiOCH3 groups on the active sites and called that ODS2.

 

I then have notes describing end-capping as the reaction of organochlorosilanes with silanol groups and an equation of SiOH + C18H37SiCl3 being silylated and hydrolysed to Si-OSiC18H37 (+ 2HCl) but thats the same as the groups on the NPHPLC.

 

If the active sites on RP HPLC are already modified how can this end-capping occur? Am confusing myself even more and can't even get the right words for my questions to make sense!:) Can anyone help again! Thank you.

 

Edit: Found the answer but can't delete this post - sorry! Will leave it in case anyone wants to answer anyway!