Notes On Fluorescence Analysis - Hitachi PRIMAIDE 1440 Instruction Manual

2.3.3 Notes on fluorescence analysis

Table 2-5 Raman Spectral Peak Position at Each Excitation Wavelength
(Excitation
Wavelength)
Excitation
wavelength, and
Raman peak
position (nm)
(1) Raman Scattering
When fluorescence is measured, two additional peaks may
appear in the spectrum. The Rayleigh peak appears at the
excitation wavelength and is due to scattered light, while
the Raman peak appears at longer wavelength than the
excitation. The position of the Raman band is dependent
on the excitation wavelength, while the position of the
fluorescence is independent of the excitation wavelength
though its peak height changes. Both Rayleigh and
Raman scatterings occur due to a solvent. Take care not
to mistake them for fluorescence peaks.
Table 3-2 presents the position of the Raman peak for a
variety of excitation wavelengths.
In liquid chromatography, the Raman scattering appears as
a background rise. This means that baseline noise
increases to disturb high-sensitivity measurement.
Water Ethanol
248 271
313 350
365 416
405 469
436 511
2 - 11
Cyclohexane
267 267
344 344
405 408
459 458
500 499
Carbon
Chloroform
Tetrachloride
— —
320 346
375 410
418 461
450 502