Page 183 - Illustrated Pocket Dictionary of Chromatography

SPECIFICITY 185

sorbent Synonymous with the packing material: It is what provides
adsorption or partition sites for analyte phase transfer.
source A generator of an output that is altered when it is directed
through a sampled. For example, a UV source can be a “continuous”
source that gives high-intensity output from 190 to 400nm (such as deu-
terium) or a high-intensity line emission source such as zinc (214nm),
cadmium (229 and 336nm), and mercury (254nm and others).

Two UV sources are shown above. The left source is prealigned in a housing that
is locked into the source chamber in the detector. The right source must be aligned
once it is placed into the source chamber.

spacer arm Used in affinity and chiral chromatographic supports
to move an enzyme-active or 3-D interaction site far enough away
from the surface so as to offer the analyte rapid and unhindered
access.
specification Defines the target level of a given chemical or phys-
ical test along with acceptable upper and/or lower limits for that test
for a particular material. For example, if the limit of free salicylic acid
in aspirin is 0.3%, then all results must be lower than this limit (upper
bounded limit). The specification for aspirin itself is a purity level with
a target of 100% and an acceptable range of ±10% (90–110%).
specificity Refers to a detector, column, or system that interacts
with only one compound.