Varian ProStar 400, Руководство по эксплуатации

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Sample Drain for Loopfilling by Headspace Pressure
Time-based loopfilling by sample headspace pressure can be
selected (see
Operation on page 17) to shorten loopfill time for
larger loop volumes (see Injection Principle on page 14).
To allow time-based loopfilling and to prevent hydrostatic sample
loss, the special sample drain for headspace pressure loopfill
must be connected at the injection valve, replacing the dispenser
connection at the valve.
Sample Consumption
Rest volume
Since the sample needle is always at some (very short) distance
above the bottom of the sample vial, a certain volume of sample
always remains in the vial, out of reach of the sample needle.
This volume is called the
rest volume .
For standard 1.5 mL vials, the rest volume is approximately
200 µL. For a conical vial, the rest volume is only a few µL.
Refer to page 30 for adjustment of needle penetration depth.
Pre-flush volume
Prior to the FIRST injection, the sample needle and tubing
(needle
→
injection valve) are flushed with sample (for dispenser
controlled loopfill, see page 14, Injection Principle ).
Depending on the concentration differences between samples
and the cross-contamination allowed, this so-called pre-flush
volume may range between 30-999 µL (programmable). Only
dispenser controlled loopfilling uses a pre-flush.
If sample loss greater than 30 µL for pre-flush is not acceptable,
select NEEDLE WASH between sample vials in SYSTEM
SETTINGS to avoid cross-contamination. See
Operation on
page 17.