Examination of Pretreatment Conditions (1) Dependency on Flow Rate

In the column switching method using acetaminophen (a hydrophilic drug), we investigated the influence of the flow rate to the analysis. The eluent volume passed through the pretreatment column was fixed (2.5mL). The flow rate was changed from 0.5 to 2.0mL/min at the step of pretreatment. Consequently, we found that the flow rate of 0.8mL/min or less was preferable to MSpak PK-2A.
Please refer to System diagram.

Sample : 2.5ppm Acetaminophen, 100micro-L

Pretreatment
Column       : Shodex MSpak PK-2A (2.0mmID*10mm)
Eluent       : 10mM CH3COONH4(pH7.0)
Column temp. : Room temp.
 
Analysis 
Column       : Shodex MSpak GF-4A (4.6mmID*10mm) x 2
Eluent       : 10mM CH3COONH4(pH7.0)/CH3CN=85/15
Flow rate    : 0.3mL/min
Detector     : UV(254nm)
Column temp. : Room temp.