OVA7000 Routine Service Manual V1.5
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3.2
Reagent Replacement and Monitoring
Reagents can usually be replaced while the OVA7000 is carrying out an analysis providing precautions are taken
to stop air from being sucked into the reagent tubes. The OVA7000 will normally use electrolyte, standard and
cell rinse solution (normally deionised water). Other applications may also use various acid and working
electrode plating solutions.
For each application cycle it will be necessary to calculate the consumption of each of these reagents and pre-
plan their replacement. If possible, plan the replacement procedure so that it can be carried out at a set time (e.g.
Friday afternoon or Monday morning) each week.
For example, an application that uses 9.5 mL of electrolyte per sample in the voltammetry cell and runs an
analysis every 15 minutes will require 912 mL of acid per 24 hours of run time. ((24 x 60)/15) x 9.5. In seven
days of continuous running approximately 7 litres of electrolyte will be required.
It is essential that each reagent is replaced when the relevant pump is not operating. Identify the longest period in
the analytical cycle that the pump does not operate. If the time the pump is off is never less than 5 minutes, it
may be advisable to stop the OVA7000 by using the
Stop
button. In this way you will not inadvertently admit air
to the reagent tubes.
3.2.1
Replacing Reagent during a Run
Replacing reagent during OVA7000 operation (Run).
1.
When the corresponding pump is off, carefully remove the flexible tubing from the reagent container to
be changed and place on a clean surface.
2.
Refill the container with fresh reagent.
3.
Re insert the flexible tubing into the container. Ensure the tubing reaches the bottom of the container.
The reagent is now ready for use.
4.
Standard lines should always be purged as they pump small volumes which must nevertheless be
accurate, so that even small air bubbles can cause a significant error
Warning: If for any reason air bubbles are admitted to the tubing, the instrument will have to be stopped and
the line will have to be purged.
3.3
Pump Calibration
Calibration allows each pump to be set for accurate delivery of the required volume. This should ideally be
carried out every week, each time the pump or pump head is replaced, when the instrument has not been used for
a few weeks or when the instrument is used for the first time.
An accurate 10 mL volumetric cylinder, or digital scales with at least 0.1 gram resolution, is required. The digital
scales can be used to accurately measure water volume by zeroing the container and reading grams as mL.
Ensure access to the OVA7000 Main screen as per section 2.1, Powering Up and Communicating with the
OVA7000 on page 7. From the Main screen select
Calibrate Pumps
. The Calibration screen will be displayed.
