Page 22 - Illustrated Pocket Dictionary of Chromatography

16 BAR

wavelengths that pass through a monochrometer in a UV-visible detec-
tor. Linearity is better as bandwidth decreases, but the trade-off is that
the radiation that reaches the sample decreases with decreasing
bandwidth and so the detection limit generally increases.
bar A unit of measure for pressure equal to ~14.7psi, 1atm, or
~0.1MPa.
baseline The operating baseline is generated by the eluent only
through the system. For isocratic or isothermal runs the baseline
should be constant with no upward or downward drifting. For a gra-
dient (composition or thermal), a shift in baseline is often expected
but should result in a smooth change in the baseline and should be
reproducible from run to run.
baseline resolution Occurs when in the case of two adjacent
peaks the least-retained peak completely elutes before the later-
eluting peak begins to elute.

In the top separation the peaks are only partially resolved. The bottom separation
shows baseline resolution, i.e., the elution profile for the first-eluting peak reaches
the system baseline before the second peak starting to elute.