5-4
Operation - Advanced Use 5
Correct Use of the 402
Aspirating Large Volumes via the
Probe
1. The valve switches to connect the left-
hand syringe to the Tee-junction and
probe.
2. The piston of the right-hand syringe
remains in the top position to prevent
liquid from entering the syringe.
3. The left-hand piston descends to
aspirate the specified volume of sample
liquid.
Aspirating Small Volumes via the
Probe
1. The valve switches to connect the left-
hand syringe to the reservoir, thus
disconnecting the left-hand syringe
from the right syringe.
2. The piston of the left-hand syringe
remains in the top position.
3. The right-hand piston descends to
aspirate the specified volume of sample.
Right-hand Syringe Dispensing to
Probe
1. The valve switches to connect the left-
hand syringe to the reservoir, thus
disconnecting the left-hand syringe
from the right-hand syringe.
2. The piston of the left-hand syringe
remains in the top position.
3. The right-hand piston ascends to
dispense the specified volume of
sample.
(c) Left-hand Syringe
Aspirating from Probe
Left piston
descends
to aspirate
Right piston
remains at
the top
From Tee From Probe
(d) Right-hand Syringe
Aspirating from Probe
Left piston
remains
inactive
Right piston
descends to
aspirate
From Probe
Valve switched
to Reservoir
(e) Right-hand Syringe
Dispensing to Probe
Valve switched
to Reservoir
To Probe
Left piston
remains
inactive
Right piston
ascends to
aspirate
