92 Agilent 1200 Infinity Series DAD User Manual
5 Optimizing the Detector
Optimizing for Sensitivity, Selectivity, Linearity and Dispersion
Slit Width (G4212A)
The 1290 Infinity DAD (G4212A) has a variable slit at the entrance of the
spectrograph. This is an effective tool to adapt the detector to changing
demand of different analytical problems.
A narrow slit provides spectral resolution for analytes with very fine
structures in the absorbance spectrum. An example of such a spectrum is
benzene. The five main absorbance bands (fingers) are only 2.5 nm wide and
just 6 nm apart from each other.
Figure 23 Benzene at 1 and 4 nm slit width (principle)
A wide slit uses more of the light shining through the flow cell. This gives
lower baseline noise as shown in Figure 24 on page 93.