effect of pH of mobile phase in HPLC

[mritunjai078]

I want to know effect of pH of mobile phase in Liquid Chromatography.

[Consumer Products Guy]

This can range from great effect to materials affected by pH (amines, phenolics, etc.) to no affect for materials not affected by pH.

You'll need to do some reading, or provide way more specifics.

[praveenpaliwal]

In simple word we r trying to hold some of ionic species in side the column. The ionization of such species r affeted by the pH and pKa values of the analytes.
In simple we can say thet if u want to analyze acid , se the acidic pH so thet u can supress the ionization and if u want to analyze base u should supress the ionization of basic analytes.
But always take care about pka values.

[HW Mueller]

Praveen, that is a bit simple, one might have situations where ionization is wanted to reduce a high retention time, or a zwitter my be needed to be shifted around. The silanolate-silanol equilibrium might need to be influenced. Weak ion exchangers might need pH control. One may want to control other solid phase chemistries like that of the graphitic carbon column (Hypercarb), etc.