Agilent Technologies InfinityLab LC Series User Manual page 133

6
Optimizing Performance
Optimization for Lowest Carry-over
of time for washing the outside of the needle with fresh solvent. This may be as
low as two or three seconds in routine situations where carryover is less of a
problem and 10 to 20 s for more complete washing. It is recommended that
washing the outside of the needle in the flush port should be standard
procedure to avoid contaminating the needle seat.
Using the Needle Wash in the Wash Vial
For very critical applications where the outside of the needle cannot be
cleaned sufficiently with one wash port solvent you can use an injector
program and an additional wash vial with an appropriate and stronger solvent
for cleaning. The wash vial should contain solvent in which the sample
components are soluble, and the vial should not be capped. If the wash vial is
capped, small amounts of sample remain on the surface of the septum, which
may be carried on the needle to the next sample.
Injector Program with Needle Wash
The injector program includes the command WASH. When this command is
included in the injector program, the needle is lowered once into the specified
wash vial or flushport before injection.
For example:
1 WASH > Location P2-A1 or flushport
2 Draw 5 μL from Sample Location P1-A1
3 INJECT
Line 1 moves the needle to vial P2-A1 or the flushport. Line 2 draws 5 μL from
the current sample vial P1-A1. Line 3 injects the sample (valve switches to
main pass).
Agilent InfinityLab LC Series Vialsamplers User Manual 133