Metrohm 881 Compact IC pro – Cation - Manual (Page 75)

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5 Operation and maintenance
881 Compact IC pro – Cation
￭￭￭￭￭￭￭￭ 67
The time measured corresponds to the "transfer time". The rinsing
time should be at least 3 times the transfer time.
Checking the rinsing time
It is possible to determine whether the rinsing time is adequate via a direct
measurement of the sample carry-over. Proceed as follows:
1 Preparing two samples
￭ Sample A: A typical sample for the application.
￭ Sample sample B: Ultrapure water.
2 Determining "Sample A"
Let "Sample A" pass through the sample path for the duration of the
rinsing time, then inject and measure.
3 Determining "Sample B"
Let "Sample B" pass through the sample path for the duration of the
rinsing time, then inject and measure.
4 Calculating the sample carry-over
The degree of the sample carry-over corresponds to the ratio of the
peak areas of the measurement for sample B to the measurement for
sample A. The lower the ratio, the lower the sample carry-over. This
ratio can be modified by varying the rinsing time – thus allowing the
rinsing time required for the application to be ascertained.
5.9 Injection valve
5.9.1 Protection
To prevent contamination of the injection valve, a 6.2821.120 inline filter
(see Chapter 3.11, page 32) should be mounted between the high pres-
sure pump and the pulsation damper.