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Intensity
distribution
[%]
r
H
Polydisperse
Polydispersity implies multiple particle sizes or types in the sample. If there are
multiple species of different sizes the intensity distribution will have multiple peaks.
If there is a single species but it is of varying folded quality or oligomeric state this
will show up as a broadening of the peaks found in the intensity distribution plot. It
is also possible for both phenomena to occur in the same sample.
Which PDI values are considered good?
A PDI value of ≤ 0.1 is considered a highly monodisperse
sample; PDIs up to 0.3 are considered mostly monodisperse;
a PDI from 0.3 to 0.7 is somewhat polydisperse; and a PDI >
0.7 is considered highly polydisperse and unsuitable for DLS.
The exact thresholds considered acceptable will vary
depending on your application. It is always a good idea to
look closely at the intensity distribution for high PDI samples
to determine if the high PDI is a result of oligomerization,
multiple species, or large aggregations.
