The Stabino® II is a second generation zeta potential instrument for analysing and optimising the stability of colloids and dispersions, based on measurement of streaming potential.
Employing a unique oscillating piston design, the system incorporates rapid pH and polyelectrolyte titrations for investigation of stable pH regions, Iso-Electric Point (IEP), charge density and surface functionalisation. The system is ideally suited to formulation development and has applications in quality control.
Fast pH & polyelectrolyte titrations – calculate IEP or charge density in minutes
High resolution zeta potential plots – based on accurate streaming potential measurements
Mix & Measure principle – oscillating piston for continuous sample mixing avoids sedimentation – often a problem when approaching the iso-electric point
Highly flexible, non-optical technique – accurate measurements including non-spherical particles, at a wide range of concentrations, up to 40% w/v
Intuitive, self-explaining software – making setting up a measurement extremely quick and easy
Market-leading post-sales support – from both Analytik and Colloid Metrix
As the exclusive distributor for the UK and Ireland, Analytik is proud to supply the Stabino® from Colloid Metrix. Through Analytik, you’ll have access to our team of experts to help develop your application and get the most out of your investment.
For more information, or to discuss your requirements with a product specialist, please call us on +44 (0)1954 232 776 or email firstname.lastname@example.org.
Zeta potential and charge titration for the rapid assessment of stability and formulation of colloids
The stability of colloidal material and dispersions is a vital factor in the development, formulation and quality assurance of new products.
Long measuring times, imprecise and non-significant measurements, due to only selective and low-resolution measurements of the zeta potential, often lead to a flawed analysis of the dispersion stability and can incur high costs. In addition, agglomeration of particles can reduce production efficiency and product quality, so a measurement method that can accurately determine the critical coagulation point is essential.
Particle surface charge and interface potentials, such as the zeta potential and the streaming potential, are widely used to characterise the stability of suspensions, emulsions and nanoparticles. These parameters are established as a typical measure representing the electrostatic repulsion between particles in order to assess the stability of colloids and dispersions.
The Stabino® II from Colloid Metrix provides fast, precise and reproducible particle charge measurements due to its high resolution and data point density. Able to measure the surface charge of particles in the range of 0.3 nm to 300 μm, with a concentration range of up to 40% by volume, its optimised measuring technology can determine 5 parameters simultaneously, within just a few seconds:
In addition, the Stabino® II has a built-in titration function where all the parameters are determined simultaneously, at every titration dosage step. The isoelectric point can be determined within a few short minutes.
pH titration: determination of the isoelectric point and stable pH ranges.
Polyelectrolyte titration: statements about the stability and charge density.
Titration with dispersant: for dispersant optimisation.
Titration with salts: zeta potential as a function of the conductivity.
Formulation: titration with additives to obtain the optimum formulations.
The Stabino affords users complete control over their experiments, giving extremely high resolution zeta potential plots thanks to its ability to titrate quickly and frequently, with potential readings taken every 5 seconds.
Interested in the Stabino®? Request a quote or call us on +44(0)1954 232 776 to discuss your requirements.
Particles become immobilised on the PTFE beaker and oscillating piston. The fluid stream moves the mobile ion cloud surrounding each particle, allowing the electrodes to measure streaming potential.
The heart of the Stabino is cylindrical PTFE measuring beaker and piston. Sample is added to the beaker and the piston oscillates at a constant frequency during measurement. Particles become immobilised on the surface of the beaker and piston, allowing the fluid stream created by the moving piston to shift the mobile ion cloud around each particle up and down, creating an oscillating frequency. The potential created is detected and measured by the two electrodes as streaming potential. From this, zeta potential is calculated.
Zeta potential alone is often not sufficient information to assess the stability of a colloid. +/-30mV is often quoted as a threshold for stability, but this does not give the full picture and is only relevant to the sample as it stands in that exact chemical environment. It is entirely possible for two samples to have -30mV zeta potential but have very different stabilities. The Stabino provides a full insight into the colloid being assessed, primarily via pH and polyelectrolyte titrations.
pH titrations – allow the assessment of stable pH regions and determination of the iso-electric point (IEP) with extremely high resolution. IEP determination via classical light-scattering methods is problematic due particles agglomerating and then sedimenting out when approaching the IEP. The Stabino constantly mixes the sample via the oscillating piston and is therefore not hindered by this problem and can measure the exact pH at which zero charge is achieved.
Polyelectrolyte titrations – by titrating a counter-charged polyelectrolyte solution, information on charge density can be estimated. This gives a much greater understanding of how stable a dispersion is. Predictions of shelf-life or stability over time can be built up using this method.
Salt titrations – allow investigation of the relationship between conductivity and zeta potential Salt titrations are relevant to applications such as protein aggregation or waste water treatment, where changing the conductivity deliberately causes particles in solution to form aggregates so they can be filtered out of solution.
Other titrations – ultimately, any titrant can be used on the Stabino and its effect on zeta potential monitored. Some custom applications may include assessing the effect of varying volumes of an additive or stabiliser, different amounts of pigment in an ink solution and so on.