Certified Particle Size Standards
Certified particle size standards from Duke Scientific Corporation are traceable to the Standard Meter through the National Institute of Standards and Technology (NIST). This feature enables laboratories to demonstrate the traceability of their analytical methods as required by ISO 9000, ISO 10012, ANSI/NCSL Z540, GMP/GLP and other standards and regulations. Duke Scientific?s particle size standards provide third party traceability of calibration procedures to national and international agencies through an unbroken chain of measurements with specified uncertainties. The products are also used to develop and test new analytical instruments for particle size characterization of materials.
They are available as uniform spheres of polymer in a range of discrete sizes from 20 nanometers (nm) to 1000 micrometers (µm or microns). The spherical diameters are calibrated with linear dimensions transferred from NIST by methods developed at Duke Scientific Corporation. Spheres are used instead of irregularly shaped particles to minimize shape effects on the response of analytical systems.
Each standards contains a Certificate of Calibration and Traceability to NIST which includes a description of the calibration method and its uncertainty, and a table of chemical and physical properties. A Material Safety Data Sheet with handling and disposal instructions is also included. Packages are lot-numbered for technical service and support after the sale.
Nanosphere Particle Size Standards
they are highly uniform polystyrene spheres calibrated in billionths of a meter (nanometers) with NIST traceable methodology. One nanometer is 0.001 micrometer or 10 Angstroms. Nanosphere Size Standards are packaged as aqueous suspensions in 15 milliliter (mL) dropper-tipped bottles. The concentrations are optimized for ease of dispersion and colloidal stability. The spheres have a density of 1.05 g/cm3 and an index of refraction of 1.59 @ 589 nm (25°C).
Nanosphere Size Standards are ideal for the calibration of electron and atomic force microscopes. They are also used in laser light scattering studies and colloidal systems research. The 20 to 900 nm range of diameters is convenient for checking the sizes of bacteria, viruses, ribosomes and sub-cellular components.
Microsphere Size Standards
The mean diameters of these products have been calibrated with Duke Scientific's NIST traceable microscopy methods. Their size distribution and uniformity were measured by electrical resistance analysis or optical microscopy. All of the Microspheres .
Products from 1 to 160 µm are made from polystyrene (PS) and packaged as aqueous suspensions in 15 mL dropper-tipped bottles, at an optimum concentration for dispersion, handling and dilution. Diameters of 200 µm and larger are made from polystyrene crosslinked with divinylbenzene (PSDVB) except for the two largest products, which are made from polymethylmethacrylate (PMMA) and packaged as dry spheres.
EZY-CAL Particle Size Standards
This product line offers a series of ready-to-use standards for validating optical particle counters with an absolute minimum of diluting or handling. The products are suspensions of polymer microspheres in water with a concentration of 2,000 particles per milliliter (ml). A magnetic stir bar is included in each bottle for clean, convenient and direct sampling by instruments with a 2-100 μm size range.
This series of monodisperse size standards is provided for setting or checking the calibration of channel thresholds at the most commonly used points. Their certified diameters are measured by methods traceable to NIST and/or BCR. They are packaged as 100 ml bottles, sufficient for four or five calibration procedures on most counters.
The microspheres are composed of polystyrene divinylbenzene, which has an index of refraction of 1.59 @ 540nm and a specific gravity of 1.05. The aqueous suspension medium contains a combination of dispersing agents which help keep the particles from clumping or sticking to flow surfaces in the particle counter.
In summary, the EZY-CAL product line meets of the unique and demanding requirements of the contamination control laboratory in modern industries.