Glossary
137
multiple headspace extraction An analytical technique that takes more
than one headspace sample from each sample vial, followed by
chromatographic analysis of each extracted sample. By summing up the peak
area for each compound, the total amount of that compound in the sample can
be determined, eliminating the effect of the matrix. See single headspace
extraction.
multiple puncture Multiple headspace extraction performed by puncturing
the septum separately for each extraction. See single puncture.
partition coefficient K (in gas chromatography.) The ratio of the amount of
a component per unit volume of the stationary phase (g cm-3) to its amount per
unit volume of the mobile phase at constant temperature and at equilibrium.
The partition coefficient is assumed to be independent of concentration at the
concentration prevailing in gas chromatography, and is related to the volume
VN by
where:
V
L
= volume of the liquid stationary phase
δ
L
= density of the liquid
m
L
= mass of the liquid
V
g
= specific retention volume
phase ratio The ratio of the volume of the mobile phase to the volume of the
stationary phase in a column
precision The agreement between the results of repeated data
quantitative analysis Analysis performed for the purpose of determining the
amount of a compound in a sample
K
VN
V
L
----------
VNδ
L
m
L
-----------------
V
g
Tδ
L
m
L
-------------------== =
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