Metrohm 889 IC Sample Center - Manual (Page 34)

4.4 Partial loopfill injection
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889 IC Sample Center
5 Switching the injection valve to INJECT
The injection valve switches to the INJECT position. The sample loop
is now part of the flow path of the eluent; the sample is transported
to the separation column. The determination is started.
Air segment with the partial loopfill injection
An air segment can be used in order to reduce the necessary volume of
sample solution. The air segment must be located at the head of the rins-
ing volume and will not be injected.
In the case of a standard needle, the rinsing volume with air segment
must be at least 30 µL for one injection, and at least 35 µL for injections
without air segments. In the case of high-viscosity samples, larger rinsing
volumes must be programmed and the rate of the syringe stroke must be
reduced in order to improve reproducibility.