Instruments

Circular dichroism (CD) measures the difference in absorbance of left- and right-hand polarised light, which can be a powerful tool for identification and characterization of chiral molecules.

The J-810 is a hybrid instrument consisting of a variable wavelength polarimeter and absorption spectrophotometer (~180-900 nm, Far-UV to Vis range). The J-810 is fitted with an Optical Rotation Dispersion (ORD) module and Peltier temperature control making it ideally suited to measure optical purity/identification of small molecules and natural products chemistry.

Circular dichroism (CD) measures the difference in absorbance of left- and right- handed polarized light of chiral molecules.  CD is commonly used to analyse the conformation of macromolecules, particularly protein secondary structure.

Linear dichroism (LD) measures the difference in absorption of light linearly polarised parallel and perpendicular to the orientation axis. LD can be used to give information about the conformation and orientation of structures with molecules that are either intrinsically oriented, or can be oriented during an experiment by external forces such as DNA complexes, fibrous proteins such as (e.g. cytoskeleton and amyloid proteins) and membrane peptides/proteins in liposomes.

The J-1500 is a hybrid instrument consisting of a variable wavelength polarimeter for CD or LD and absorption spectrophotometer (~180-900 nm, Far-UV to Vis range). The J-1500 is fitted with a 6-position multi-cell changer and computer controlled Peltier cooling/heating system. This set-up is ideally suited to:

• Determine protein secondary structure and analyse conformational changes
• Nucleic acid structure determination and changes upon binding or melting
• Other thermodynamic parameters and kinetics based measurements

The V-760 is a double-beam UV-Visible absorbance spectrometer that measures light absorption, reflectance or transmittance in the visible to ultraviolet region (187-900 nm).  The extended photometric linearity of the V-760 (up to 8 AU) enables measurement of highly absorbing samples which is particularly useful for materials with low transmission properties such as solid films. The V-760 can also be used in conjunction with a computer controlled Peltier cooling/heating system for fixed temperature and thermodynamic measurements.

The Zetasizer Nano is a combined light scattering system suitable for characterisation of colloid dispersions, nanoparticles and macromolecules such as polymer and protein solutions (3.8 nm to 100 μm, concentration ~0.1ppm to 40%w/v, pH 1-13, sample dependent).

Dynamic Light Scattering (DLS) is used to measure the diffusion of particles under Brownian motion, and convert this to a size distribution using the Stokes-Einstein relationship. Non-invasive back-scatter (NIBS) technology is incorporated to give better sensitivity and the ability to measure particles at high concentration.

Electrophoretic Light scattering (ELS) is used to measure zeta potential. An electric field is applied to the sample and mixed mode measurement, phase analysis light scattering (M3-PALS) is used to measure electrophoretic mobility and determine a zeta potential distribution.

Static Light Scattering (SLS) is used to determine the molecular weight (> ~1KDa) of proteins and polymers. The scattering intensity at a range of concentrations is measured to construct a Debye plot. From this the weight-average molecular weight and second virial coefficient can be calculated to provide a measure of protein solubility.