Glossary
187
radial axis: a direction describing the horizontal (forward and backward)
movement of the tray’s arm. The tray uses this motion to position the vial
gripper at the correct distance from the center of the tray. See also home
positions.
retention time: the time it takes from the moment of injection until a
compound elutes and is detected at the peak maximum.
run: a discrete analysis performed under a given set of conditions on one
instrument.
run time: the time, during the run, that has elapsed from the initiation of data
acquisition (or time of injection). For completed runs, this term refers to the
total time from injection (or initiation of data acquisition) to the end of the run
(or termination of data acquisition).
sample: a liquid, gas, solid, or heterogeneous portion of material that is
representative of the whole.
sample carryover: any memory of the previous sample shown in the
chromatogram.
After an injection, the syringe retains a volume of sample in the needle and
between the plunger and barrel that ranges from 0.6 to 1 µl. Normal laboratory
practice requires washing the syringe with a solvent and/or the next sample to
dilute and wash away the remaining sample.
The first two chromatograms show the effect of carryover when 1 µl from a vial
of methanol is injected after 1 µl from a vial of a solute dissolved in methanol.
The peaks in the second chromatogram are from the solute left in the syringe
from the first injection.
To Next Page
Loading...
