Agilent Technologies 1220 Infinity II LC User Manual page 128

8
Detector Description
Agilent 1220 Infinity II LC Diode Array Detector (DAD)
Figure 41
A wide slit uses more of the light shining through the flow cell. This gives
lower baseline noise as shown in
Figure 42
However, with a wider slit, the spectrograph's optical resolution (its ability to
distinguish between different wavelengths) diminishes. Any photodiode
receives light within a range of wavelength determined by the slit width. This
explains why the fine spectral structure of benzene disappears when using a
16-nm wide slit.
Furthermore, the absorbance is no longer strictly linear with concentration
for wavelengths at a steep slope of a compound's spectrum.
128
Benzene at 1, 4 and 16 nm slit width (principle)
Influence of the Slit Width on Baseline Noise
Figure 42 on page 128.
1220 Infinity II LC System User Manual