Easy characterisation of dilute polymer solutions
by static light scattering
Characterising dilute polymer
solutions using static light scattering (SLS)
has never been easier, more accurate or better
value.
The BI-MwA uses a diode laser with detection via
seven integrated optical fibres to determine the
intensity of scattered light as a function of
angle and polymer concentration. From this information,
one of three plots is constructed with the standard
BI-MwA/ZP software: Zimm, Berry, or Debye. From
such plots the weight-average molecular weight,
Mw, the root-mean-square radius (radius of gyration),
Rg, and the second virial coefficient, A2, are
calculated. The BI-MwA can be used in batch or
flow mode, as a chromatography detector, or for
following the kinetics of polymerisation using
ACOMP, time-dependent static light scattering.
Most importantly, the BI-MwA has the highest performance/price
ratio of any light scattering detector used for
molecular weight determination.
A
significant application of the new BI-MwA is as
a component part of a GPC / SEC system to provide
much more detailed and accurate molecular weight
information for the separated polymer fractions
as they elute from the column. The great advantage
is that true molecular weight is determined absolutely,
without requiring pre-calibration, thereby eliminating
the errors inherent in using comparative methods
based on polystyrene or similar "standards".
Applications
SLS is an absolute technique for Mw determination
and, unlike viscosity measurements, requires no
calibration.
The BI-MwA is ideal for studying synthetic and
natural polymers in solution, including proteins
and polysaccharides. It can be used to investigate
macromolecular conformations, formation of oligomers
and complexes or to study aggregation and stability.
In some cases, shape information may be determined
by plotting log Mw vs log Rg; the slope of the
line can indicate whether the molecule is coiled,
rod-like or spherical. Molecular weights from
a few hundred (e.g. sugars) up to several million
can be determined using the BI-MwA.
For more
information on the the BI-MwA and its applications,
please contact us via the enquiry
form.
BI-MwA
Specification::
Angles:
35,50,75,90,105, 130, 145 plus reference
Fibres:
Low numerical aperture, integral with cell
Cell volume:
100µL (scattering volume 20nL)
Laser:
30mW, 660nm
Detector:
Ultra-high sensitivity CCD
Inputs:
Standard: 4 with 16 to 24 bit resolution.
Optional: Further 16 with 24 bit resolution.
Suitable for use with most RI, UV, viscometer
detectors and injectors, thermocouples, pump
outputs etc. Computer selectable gain.
Dimensions:
195(H) x 380 (W) x 210 (D) - alternative
format compatible with popular stacking GPC
component formats available soon.
Computer:
Requires external PC with USB interface.
Software:
BI-MwAZP for molecular weight by Zimm, Berry
or Debye Plot; BI-ACOMP for polymerisation
monitoring (TSDLS); WinGPC (LE) for GPC/SEC
mode.
