Biological sample was analyzed directly using ODP2 HP. ODP2 HP is polymer based reversed phase column. One of advantage of ODP2 HP is very low adsorption of protein, because the surface of the packing material is high polar and the pore size is small. Since proteins like BSA are eluted early and its peak shape is sharp. ODP2 HP can separate drugs from proteins. Four LC/MS chromatograms of barbital were shown. These are comparison of using ODP2 HP and ODS, and barbital without BSA and with BSA. In using ODS (right), the peak height of barbital with BSA were lower than without BSA. It means there was ion suppression by existence of BSA. The comparison data of recovery of barbital also showed influence of BSA to ODS. ODP2 HP can be used for analysis of low molecular compounds in biological sample without bad influence of protein.
Sample : Barbital (500ng/L) in BSA (7.0mg/L), 10μL 1. Barbital
Column : Shodex ODP2 HP-2B, ODS from other manufacturer(2.0mmI.D. x 50mm each)
Eluent : 10mM Ammonium acetate/CH3CN=70/30
Flow rate : 0.2mL/min
Detector : ESI-MS (SIM negative)
Column temp. : 30°C