PerkinElmer Raman Flex 400 Series, Getting Started Manual

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50 . RamanFlex 400 Series Getting Started Guide
Figure 14 Fiber optic probe with the immersion sleeve detached
Non Immersion
When using 785 nm lasers, many types of glass exhibit fluorescent bands between
1400–1600 cm
−1
. Spectra of the glass container should be obtained before analyzing the
sample to ensure that glass-derived fluorescence bands do not pose a problem. With 785 nm
excitation, fused silica (quartz) should be used instead of glass where possible as this does
not yield fluorescent peaks. Pyrex is also excellent for Raman analysis.
If glass fluorescence is a problem and it is not possible to use quartz containers, then it is
possible to acquire a spectrum of the container, and then spectrally subtract this from any
spectra containing this fluorescent signature.
When working through containers it is best to try different probe positions. If the liquid of
interest is not absorbing it may be best to focus through the container by placing the FOP in
contact with the container.
Sampling Slurries / Highly absorbing species
Please refer to
Sampling Liquids
. For sample immersion care taken in focusing the probe
within the sleeve can result in a dramatic improvement in spectral quality.
Gas Sampling
Although Raman scattering from gas samples is very weak, the FOP can be used to measure
gas phase under long acquisition times.
Immersion
sleeve
Fiber optic probe