Several important new features have recently been added to the Brookhaven 90Plus Nanoparticle Size Distribution Analyser.
Brookhaven's 90Plus is a compact dynamic light scattering (DLS) instrument designed for routine high quality analysis of the particle size distributions of submicron particles and droplets - suspensions and emulsions.
The recently announced 9010AT digital correlator is an integral part of the 90Plus specification and brings benefits which include significantly reduced power consumption compared with previous models.
The 90Plus is now available with a choice of photomultiplier (PMT) or avalanche photodiode (APD) detectors.
The APD enhances the already high sensitivity which results from the use of a high power - 30mW - laser diode source enabling the 90Plus to be used to determine the sizes of protein molecules such as lysozyme (radius 1.6nm) in solution by the DLS technique.
The increased sensitivity also improves results with samples such as liposomes which, due to their optical properties, scatter light only weakly.
The 90Plus can also be used to determine molecular weights of polymers in solution by a DLS technique involving the Mark - Houwink - Sakurada relationship.
However, this requires knowledge of other parameters of the polymer-solvent combination which may not be readily available.
Molecular weight capabilities are greatly enhanced by the newly introduced 90PDP option for the 90Plus.
This enables the system to be used in static light scattering mode (SLS) to determine absolute mean molecular weights by the Debye Plot method which involves simply making a series of measurements at different polymer concentrations.
This is facilitated by the 40 microlitre capacity flow-through sample cell which is part of the 90PDP package and which is also available separately.
Particle size analysis is increasingly used in quality assurance and for critical applications, for example in the pharmaceutical sector, the 90Plus software is now available in a fully 21CFR Part 11 compliant version.
The standard version of the software already includes useful Statistical Process Control (SPC) plots.
To complement its particle size and molecular weight analysis capabilities, the 90Plus can be made even more versatile by the addition of Brookhaven's ZetaPlus and/or ZetaPALS options for determining zeta potentials.
Brookhaven pioneered the PALS technique (phase analysis light scattering) and the ZetaPALS is the only instrument able to make zeta potential measurements solely using PALS technology.
With powerful built-in computer, the 90Plus is an excellent all-round particle and polymer characterization system ideally suited to formulation studies and many other applications involving colloidal or nanoparticle systems.
