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Using the Manual Injection Valve
How Much Sample Is Actually Injected?
5 Slowly inject sample.
6 Leave syringe in position and move valve to INJECT position.
7 Remove syringe.
How Much Sample Is Actually Injected?
When the sample loop is completely filled, the amount of sample injected is equal to
the volume of the sample loop plus the volume of the valve passages (1 in rotor and
2 in stator). This means that the actual amount of sample injected will be different to
the nominal value designated to your sample loop. However, since both standards
and samples are analyzed using the same loop, you rarely need to know the absolute
volume of the loop.
If you do need to know the actual volume of a sample loop, we recommend you
calibrate it fitted to the valve, so that you also take the valve passages into account.
How Much Sample Do I Need?
To completely fill the sample loop an excess of sample is required. This is about 2 to
3 loop volumes of sample to achieve 95 % of the maximum loop volume (the
remainder is residual mobile phase in the sample loop). Determine the optimum
number of loop volumes experimentally for your particular application.
When you partially fill the sample loop, do not inject more than half of the sample
volume. As you inject your sample into the loop, the sample mixes with the solvent
already in the loop and some of the sample could be lost through port 6 if you try to
inject too much.
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