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Isco 4700 Refrigerated Sampler
Section 4 Operation
4.4 Grab Samples
4.5 Calibrate Sample
Volumes
4-8
Grab samples let you take a single sample on demand and col-
lecting it in an external container. You can collect a grab sample
while the sampler is running a program, paused, or at the Main
Menu screen.
To collect a grab sample:
1. Press the GRAB SAMPLE button.
2. The sampler asks how much liquid to collect. To collect a
sample volume defined by pump counts, select USE
DEFINED SAMPLE. To collect a different volume, select the
ENTER SAMPLE VOLUME, then use the Number buttons
to enter the desired grab sample volume.
Note
If you selected the USE DEFINED SAMPLE option, the sam-
pler will collect the sample volume according to the DEFINED
SAMPLE calibration setting. For more information on this fea-
ture see the example "Defining the Sample Volume" on page
3-21.
3. The sampler displays GRAB SAMPLE PRESS (enter)
WHEN READY and waits for you to prepare to collect a
grab sample. Pull the lower pump tube from the bulkhead
fitting. Hold the end of the tube over a container. Press the
Enter button when you are ready.
4. The sampler goes through a complete sample collection
cycle and deposits the requested amount of liquid in the
container.
5. Return the pump tube to the bulkhead fitting.
Note
If a grab sample is taken while a program is running, it is not
counted as part of the number of samples.
The sampler can deliver sample volumes repeatable to ±5 ml or
±5% of the average volume in a set. For accurate sample
volumes, the sampler uses the suction line length (section 3.3.3)
to generate pump tables. The pump tables along with the liquid
detector are used to determine the suction head height and
measure the liquid volume. By calculating the suction head, the
delivered volumes are not affected by varying liquid levels.
Note
Incorrect suction line values, disabling the liquid detector, and
worn pump tubes may adversely affect the sample volume
accuracy.
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