PerkinElmer CLARUS 590 GC, User Manual

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Glossary of Clarus GC Terms . 19
Glossary of Chromatographic Terms
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Adsorption
– A process that occurs at the surface of a liquid or solid as a result of the attractive forces
between the adsorbent and the solute. These forces may be physical or weakly chemical.
Analysis
– The complete investigation of a sample by gas chromatographic separation including
identification of the sample components and quantitative measurements.
Anode
– The negatively charged electrode in any electrical circuit to which charged particles and ions are
attracted.
Band Broadening – A process that occurs in the GC whereby the peak width for a component increases
the longer the component travels through the column.
Baseline
– The detector signal to a recorder or integrator when only the carrier gas is passing through
the detector.
Baseline drift
– Any regular change occurring in the baseline signal from the detector, usually resulting
from column temperature and/or gas flow changes.
Blank run
– A run without the sample being injected.
Bleed
– The evaporation of the stationary phase from a column.
Capillary column
(wall coated open tubular column) – A small-internal-diameter column whose inside
wall is coated with a liquid phase.
Carrier gas – The mobile phase of the separation system. An inert gas which transports the sample
from the injector through the column to the detector. This gas is usually helium, hydrogen, or nitrogen.
Column conditioning
– A process for producing a stable column by heating the column with carrier gas
flowing to remove volatile impurities from the stationary phase.
Detectors
– Hardware that responds to sample components producing an electrical signal that can be
measured to quantitate the amount of each component present.
Flow programming
– The stored PPC program is interpreted as real column mass flow settings or
capillary column flow settings from which the inlet pressure is calculated. This is dependent on the
capillary control mode and installed pressure or split control option.
Flow rate – The mass flow of carrier gas or detector gas in milliliters per minute.
Ghost peaks
– Peaks that are not due to sample components, for example, peaks produced by carrier
gas impurities, septum, or components from previous analyses..
Injection port
– The hardware through which the sample is introduced to the column by injection.
Linearity
– Quantitatively all detectors will produce a linear response with respect to solute
concentration over a defined range, for example, the Linear Range.
Liquid phase
– The material in the column that causes the components to separate because of
partitioning of the components between the mobile phase (carrier gas) and the stationary phase (liquid
phase).
Low est limit of detection – The smallest amount of sample that can be detected by the detector being
used. Usually defined as any signal that is as great as two times the noise level. Also referred to as
Minimal Detectable Quantity (MDQ).
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Reference: Denney, R.C. A Dictionary of Chromatography.