Jordi Labs provides particle analysis for a range of materials.
Dynamic Light Scattering (DLS) or Photon Correlation Spectroscopy (PCS) or Quasi-eleastic Light Scattering (QELS)
The sample is analyzed by utilizing the effect of Brownian motion to calculate the hydrodynamic radius of a molecule in solution. The hydrodynamic size depends on the mass of the material and its conformation. This method determines particle size based on the scattering of light for particles in the sub micron to nanometer range. This method is particularly useful for identifying small amounts of aggregation in protein or polymer samples (<0.01% by weight). This method is prefered as compared to Laser Light Scattering when analyzing materials in the nanometer size range.
Electrozone Sensing Particle Size Analysis (L-Zone)
Particle size information is obtained by L- Zone through the measurement of the conductivity of the solution as the particles pass through a sensing zone. The presence of the particle within the sensing zone displaces a volume of liquid and thus reduces the measured conductivity. The momentary decrease in the current results in an electric pulse whose amplitude is proportional to the volume of electrolyte solution displaced. This allows the determination of the particle size. The instrument then sums the number of particles of a particular size passing through the sensing zone over a specific period of time. A plot of the particle size distribution is then obtained. The volume is measured directly but the size is reported as the equivalent spherical size and equals the size of a sphere that displaces the same volume of liquid. Particle sizes ranging from .4-1200µ can be analyzed by this method.
Laser Light Scattering Particle Size Analysis
A particulate sample is passed through a monochromatic, collimated light beam. Light is scattered at various angles relative to the incident beam. The intensity of the light and its angularity is then related to particle size based on Mie and Fraunhofer theory. The measured particle size is also a function of the wavelength of incident light and the relative refractive index of the suspension fluid and particle.
Samples containing a range of particle sizes result in a pattern of scattered light which is the summation of all the contributions of intensity by each particle at each angle. Particle sizes ranging from .1-1000µ can be analyzed by this method.
Particle Size and Shape Analysis by Light Microscopy
Sample images are obtained by placing the sample on a glass slide and observing the light transmitted through the sample. This technique is best for samples which are partially transparent or for the observation of fine powders (1-20µm). Digital images of the sample are captured allowing the determination of object size. This technique is useful for the observation of particulates as small as 1µm in diameter.
Porosimetry Analysis by Mercury Intrusion (PoreMI)
Mercury intrusion porosimetry involves placing the sample in a special sample cup (penetrometer), then surrounding the sample with mercury. Mercury is a non-wetting liquid to most materials and resists entering voids, doing so only when pressure is applied. The pressure at which mercury enters a pore is inversely proportional to the size of the opening to the void. As mercury is forced to enter pores within the sample material, it is depleted from a capillary stem resevoir connected to the sample cup. The incremental volume depleted after each pressure change is determined by measuring the change in capacitance of the stem. This intrusion volume is recorded with the corresponding pressure or pore size. Mercury porosimetry is applicable to pores from 30 Angstroms up to 900 micrometers in diameter.
Surface Area and Porosimetry Measurements (Porosimetry)
Sample surface and porosity measurements are made based upon gas sorption. A static volumetric technique of operation is applied which adapts the required rate at which gas is supplied for equilibration. This method of dosing and accounting for the volume of gas uptake enables the acquisition of highly accurate, highly reproducible results in the minimum time. Nitrogen is typically applied as the adsorptive gas.