Loading and End Capping

The carbon loading is a measure of the carbon content of the silica bonded stationary phase. It is normally quoted as a percentage (some examples are given in Table 6.4). A higher amount of carbon loading has the following advantages  

It results in a more hydrophobic stationary phase. A more hydro-phobic stationary phase results in increased retention and therefore better resolution of hydrophobic analytes. It should be noted, however, that a higher carbon loading does not always result in a better separation. This is of particular significance when dealing with highly nonpolar analytes. In this case, a more hydrophobic stationary phase will have a greater attraction for the nonpolar analyte and may mean that retention times are excessive or that the analyte is retained completely. 

It provides greater column capacity. This allows for a larger sample amount to be injected onto the column, either as a more concentrated 

Column Type Manufacturer Carbon Loading (%) Application 

ODS-L Capital HPLC 15 Highly polar analytes (e.g., sugars) 

---

Carbon loading and end capping will there be interaction with residual silanol groups or do you need to be able to inject highly concentrated solutions, possibly at high pH ... 

---