Metrohm 930 Compact IC Flex ChS Manual page 89

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930 Compact IC Flex ChS (2.930.1200)
3 Aspirating the sample and measuring the time
Aspirate a sample typical for the later application and use a stop-
watch to measure the time the sample needs to go from the sample
vessel to the end of the sample loop.
The time upon stopping the watch is the "transfer time".
4 Tightening the sample loop again
Tighten the sample loop again.
If the sample is injected automatically, the rinsing time must be at least
three times the transfer time.
Checking the rinsing time
You can determine if the applied rinsing time is sufficient by measuring the
sample carry-over directly. Proceed as follows to do this:
1 Preparing two samples
Sample A: A typical sample for the application.
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Sample B: Ultrapure water.
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2 Determining "Sample A"
Allow "Sample A" to run through the sample path for the duration of
the rinsing time; inject and then measure it.
3 Determining "Sample B"
Allow "Sample B" to run through the sample path for the duration of
the rinsing time; inject and then measure it.
4 Calculating the sample carry-over
The sample carry-over corresponds to the ratio of the peak areas of
the measurement from Sample B to the measurement from Sample
A. The smaller this ratio, the smaller the amount of sample carry-
over. This ratio can be changed by varying the rinsing time. This can
be used to determine the required rinsing time for the application.
5 Operation and maintenance
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