The Sofica instrument used a water cooled mercury vapor lamp as its light source. The measuring cell

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The Sofica instrument used a water cooled mercury
vapor lamp as its light source. The measuring
cell would be immersed in a liquid chosen to
eliminate errors and simplify calculations, as
well as providing efficient thermal control. The
detector was a semi-automatic photomultiplier
tube which could rotate through various angles.
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Light scattering Photometer
Sofica Instrument

• Solution immersed in constant temperature bath
• Photomultiplier tube picks up scattered light at
  various scattering angles q (rotated
  manually or automatically)

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Light scattering Photometer Dawn F (Wyatt
Technology)
Multi angle diode array means angular intensity
pattern can be obtained almost
instantaneously without rotation of a
photomultiplier tube
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Light scattering Photometer Dawn F (Wyatt
Technology)
18-angle light scattering detector for HPLC. 30mW
Gallium-arsenide laser light source.
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Dawn F Whats underneath the lid?!
photodiode detectors
incident beam
transmitted beam
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Molecular Weight Zimm plot
106.(Kc/Rq)
1/Mw
sin2(q/2) kc (k100)
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Polydisperse materials couple Dawn-F on line to
size exclusion chromatography
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Molecular Weight SECMALLS
Intensity
Elution Volume
Scattering Angle
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Molecular Weight SECMALLS
Colonic mucin
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Wyatt Technology developed this three angle
version of the DAWN-F instrument. The use of a
solid state laser allowed the footprint of laser
light scattering instrumentation to be reduced
greatly. The miniDAWN laser operates at 690 nm
and the instrument is capable of measuring a
molar mass range from a few hundred daltons to
greater than one million daltons.  Molecular
sizes may also be measured ranging from 10 to 50
nm.
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