Metrohm 889 IC Sample Center - Manual (Page 27)

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4 Functioning
889 IC Sample Center
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4 Functioning
4.1 Injection modes
Three different injection modes can be utilized:
￭ Full loop injection: for full precision
￭ Partial loopfill injection: for full flexibility
￭ Pickup injection: for smallest loss of sample
The sample loop injection with pressure-assisted sample aspiration =
PASA
™ can be used with all three injection modes. This is a tried and tes-
ted concept which combines high accuracy with simplicity and reliability.
￭ No movement of the sample needle
￭ Reduced risk of bubbles in the sample intake
￭ No wearing or contamination of the injection port
1
2
3
4
5
Figure 12 PASA ™ injection concept
1 Buffer loop 2 High pressure pump
3 Separation column 4 Sample loop
5 Compressed air
The syringe aspirates the sample out of the sample vessel and into the
sample loop. The buffer loop between the syringe and the injection valve