Precise Injection Volume; Draw And Eject Speed - Agilent Technologies InfinityLab LC Series User Manual

6
Optimizing Performance

Precise Injection Volume

Precise Injection Volume

Injection Volumes Less Than 2 µL
When the injection valve switches to the BYPASS position, the mobile phase in
the sample loop is depressurized. When the syringe begins drawing sample,
the pressure of the mobile phase is decreased further. If the mobile phase is
not degassed adequately, small gas bubbles may form in the sample loop
during the injection sequence. When using injection volumes < 2 μL, these gas
bubbles may affect the injection-volume precision. Use degassed mobile
phases for best injection-volume precision with injection volumes < 2 μL.
If the pump has no degasser, it is recommended to use an Agilent 1260 Infinity
degasser.
Also, using the automated needle wash (see
Carry-over"
minimum, further improving the injection volume precision.

Draw and Eject Speed

Draw Speed
The speed at which the metering unit draws sample out of the vial may have an
influence on the injection volume precision when using viscous samples. If the
draw speed is too high, air bubbles may form in the sample plug, affecting
precision. The default draw speed is 100 μL/min. This speed is suitable for the
majority of applications, however, when using viscous samples, set the draw
speed to lower speed for optimum results. A DRAW statement in an injector
program also uses the draw speed setting which is configured for the
autosampler.
138
on page 132) between injections reduces carry-over to a
Agilent InfinityLab LC Series Vialsamplers User Manual
"Optimization for Lowest