Agilent InfinityLab LC Series 1260 Infinity II FLD User Manual
123
Optimizing the Detector
5
Finding the Best Wavelengths
A Real Example
Although an excitation wavelength of 340 nm is quoted in the literature the
module scan of orthophthalaldehyde, a derivative of the amino acid alanine,
(
on page 123) shows a maximum between 220 nm and 240 nm.
Figure 45
Scan Orthophthalaldehyde Derivative of Alanine
When you are looking for the wavelength by scanning, scan over the whole
range. As this example shows a maximum may be found in a completely
different wavelength range.
N O T E
When comparing fluorescence excitation spectra directly with DAD spectra or literature
based absorbance spectra, you should consider large differences in the used optical
bandwidth (FLD = 20 nm) which cause a systematic wavelength maximum shift depending
on the absorbance spectrum of the compound under evaluation.
