Agilent Technologies G1367A, Reference Manual

Page: 49 / 286

Optimizing Performance
2
1100 Series WS MWS Reference Manual 49
Fast Injection Cycle and Low Delay Volume
Short injection cycle times for high sample througput is one of the main issues
in analytical laboratories. Shortening cycle time starts with:
• shortening column length
• high flow rate
• steep gradient
Having optimized these parameters, further reduction of cycle times can be
obtained using the overlapped injection mode.
Overlapped Injection Mode
In this process, as soon as the sample has reached the column, the injection
valve is switched back to bypass and the next injection cycle starts but waits
with switching to mainpass until the actual run is finished. You gain the
sample preparation time when using this process.
Switching the valve into the bypass position reduces the system delay volume
by approximately 300 µl (the mobile phase is directed to the column without
passing sample loop, needle and needle seat capillary). This can help to have
faster cycle times especially if low flow rates have to be used like it is
mandatory in narrow bore and micro bore HPLC.
N O T E
Having the valve in bypass position can increase the carry-over in the system.