The molecular size or hydrodynamic radius RH can be determined in two ways. The first method is by Dynamic Light Scattering (DLS), which is generally used as a batch technique to measure the average size in the whole sample, but can be used as a detector for Size Exclusion Chromatography (GPC/SEC).

When measuring molecular size a very accurate and precise method of obtaining RH of all components in a sample is by triple detection after separation by SEC.

By the use of online light scattering and viscometer detectors, the MW and intrinsic viscosity of the polymer or protein can be determined and hence the RH calculated at any point on the chromatogram.

The benefit of both these techniques is that there is no practical upper or lower size limit for the materials being investigated.

The measurement of molecular size is a useful parameter for a number of applications:

  • Comparison with molecular weight gives information about structure
  • DLS can use molecular size to give a quick estimate of molecular weight
  • DLS can give a fast screen of protein purity
  • Determination of protein melting point.

OMNISEC

OMNISEC

The world’s most advanced multi-detector GPC/SEC system

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Measurement Molecular structure, Molecular size, Molecular weight
Molecular weight range 200Da - 10MDa
Minimum sample mass (polystyrene) 100ng
Minimum sample mass (BSA) 100ng
Technology Gel Permeation Chromatography, Size Exclusion Chromatography (SEC), Light Scattering, Static Light Scattering

Zetasizer range

Zetasizer range

The world’s most widely-used systems for nanoparticle, colloid and biomolecular particle sizing and particle charge measurements

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Measurement Molecular size, Molecular weight, Particle size, Zeta potential
Temperature range 0°C - 120°C
Particle size range 0.3nm - 10µm
Technology Light Scattering, Dynamic Light Scattering, Electrophoretic Light Scattering, Static Light Scattering
Dispersion type Wet
Sample cell type Cuvette
Molecular measurement type Chromotography, Batch measurement

Empyrean Nano Edition

Empyrean Nano Edition

Versatile X-ray scattering platform

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Measurement Molecular weight, Particle shape, Particle size, Surface area, Protein aggregation, Protein stability, Phase identification, Phase quantification, Pore size distribution
Goniometer configuration Vertical goniometer, Θ-Θ
Particle size range 1 - 100 nm
Technology X-ray Diffraction (XRD), X-ray Scattering

OMNISEC

OMNISEC

The world’s most advanced multi-detector GPC/SEC system

Zetasizer range

Zetasizer range

The world’s most widely-used systems for nanoparticle, colloid and biomolecular particle sizing and particle charge measurements

Empyrean Nano Edition

Empyrean Nano Edition

Versatile X-ray scattering platform

More details More details More details
Measurement Molecular structure, Molecular size, Molecular weight Molecular size, Molecular weight, Particle size, Zeta potential Molecular weight, Particle shape, Particle size, Surface area, Protein aggregation, Protein stability, Phase identification, Phase quantification, Pore size distribution
Molecular weight range 200Da - 10MDa    
Minimum sample mass (polystyrene) 100ng    
Minimum sample mass (BSA) 100ng    
Temperature range   0°C - 120°C  
Particle size range   0.3nm - 10µm 1 - 100 nm
Goniometer configuration     Vertical goniometer, Θ-Θ
Technology Gel Permeation Chromatography, Size Exclusion Chromatography (SEC), Light Scattering, Static Light Scattering Light Scattering, Dynamic Light Scattering, Electrophoretic Light Scattering, Static Light Scattering X-ray Diffraction (XRD), X-ray Scattering
Dispersion type   Wet  
Sample cell type   Cuvette  
Molecular measurement type   Chromotography, Batch measurement  

OMNISEC

Zetasizer Advance Range

Empyrean Nano Edition

OMNISEC Zetasizer Advance Range Empyrean Nano Edition

The world’s most advanced multi-detector GPC/SEC system

Light Scattering for every application

Versatile X-ray scattering platform

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Measurement type
Molecular structure
Molecular size
Molecular weight
Technology
Gel Permeation Chromatography
Size Exclusion Chromatography (SEC)
Dynamic Light Scattering
X-ray Diffraction (XRD)