Determining the Injection Type (AS/AS50)

Autosampler Control
Determining the Injection Type (AS/AS50)

The AS or AS50 Autosampler can perform the following types of injections:

Injection Type	Description
Full	Full-loop injection to one system
Partial	Partial-loop injection to one system
Partial LS	Partial-loop, limited-sample injection to one system (no extra sample is aspirated)
Large Loop	Large-loop injection to one system
Simultaneous	Full-loop injections to two systems simultaneously
Concentrate	Concentrate injection to one system
Sequential Full	Full-loop injections to two systems alternately
Sequential Partial	Partial-loop injections to two systems alternately
Sequential Partial LS	Partial-loop, limited-sample injections to two systems alternately
Sequential Large Loop	Large-loop injection to two systems alternately
Sequential Concentrate	Concentrate injections to two systems alternately

The injection type is selected automatically, depending first on the sample mode selected on the System Parameters screen on the AS or AS50 (USB) front panel. The possible sample modes are Normal, Simultaneous, Concentrate, Sequential, and Sequential Concentrate.

For Normal and Sequential sample modes, the injection type is further determined by the following criteria:

A full-loop injection is performed when the Inj. Vol. (injection volume) is greater than the Loop Volume. The injection volume is entered in the Sequence. The loop volume is entered on the Plumbing Configuration screen on the AS or AS50 front panel.
A large-loop injection is performed when the loop volume is 200.0 to 7000.0 ml.
A partial-loop injection is performed when the injection volume is less than the loop volume and the cut volume is greater than 0. The cut volume specifies a volume of sample to be cut or discarded from each side of the aspirated sample during the injection process. The cut volume is entered in the Program.
A partial-loop, limited-sample injection is performed when the injection volume is less than the loop volume and the cut volume is 0.

The table below shows the volume of sample the autosampler aspirates from the sample vial or well plate well and the volume of sample injected onto the column.

Injection Type	Sample Volume Aspirated	Sample Volume Injected
Full-loop (2.5 to 16.9 mL loop)	Injection volume or 2.5 X loop volume + 25 ml (whichever is greater)	Loop volume
Full-loop (17.0 to 199.9 mL loop)	Injection volume or 4 X loop volume (whichever is greater)	Loop volume
Large-loop (200.0 to 7000.0 mL loop)	Injection volume or 1 X loop volume + 500 mL (whichever is greater)	Loop volume
Partial-loop	Injection volume + 2 X cut volume	Injection volume
Partial-loop, limited sample	Injection volume	Injection volume

Tips:

If the AS or AS50 (USB) is in Simultaneous mode, the autosampler can perform full-loop injections only.

For the best accuracy when performing partial-loop injections, specify an injection volume equal to half the loop volume or less.