Agilent Technologies Agilent 1260 Infinity System User's Manual page 62

3
Optimization of the Agilent 1260 Infinity Binary LC
How to Achieve Higher Sensitivity
Columns
Sensitivity is specified as a signal- to- noise ratio (S/N) and hence the need
to maximize peak height and minimize baseline noise. Any reduction in
peak dispersion will help to maintain peak height and so extra- column
volume should be minimized by use of short, narrow internal diameter,
connection capillaries and correctly installed fittings. Using smaller inner
diameter columns should result in higher peak height and is therefore
ideal for applications with limited sample amounts. If the same sample
amount can be injected on a smaller i.d. column, then the dilution due to
column diameter will be less and the sensitivity will increase. For
example, decreasing the column i.d. from 4.6 mm to 2.1 mm results in a
theoretical gain in peak height of 4.7 times due to the decreased dilution
in the column. For a mass spectrometer detector, the lower flow rates of
narrow columns can result in higher ionization efficiencies and therefore
higher sensitivity.
Detector Settings
The detector has a number of parameters that are used to optimize
performance. The following sections describe how the detector parameters
affect performance characteristics:
• Flow cell affects sensitivity,
• Wavelength and bandwidth affect sensitivity, selectivity and linearity,
• Slit Width affects sensitivity, spectral resolution and linearity,
• Peak Width affects sensitivity and resolution.
62 1260 Infinity Binary LC - System User Guide