Particle Size Standards and Microspheres

• Certified Particle Size Standards
  
• General Purpose Microspheres & Particles
  
• Fluorescent Microspheres
  
• Reagent Microspheres
  
• Standards for Particle Counting Methods
  
• Particles for Special Applications
  
• Microspheres For Flow Cytometry

Fluorescent Microspheres and Particles

Fluorescent microspheres and particles emit bright and distinctive colours when illuminated by light of shorter wavelengths. This property improves their contrast and visibility relative to background materials. In addition to the features of conventional microspheres and particles, the fluorescent products offer extra sensitivity and detectability for analytical methods. The products can be stored at room temperature and can be dispersed in aqueous media or air without degrading their fluorescent properties.

Typical applications include: testing of filtration media and systems, vial and container cleaning studies, flow tracing and fluid mechanics, medical imaging and flow cytometry, fluorescence microscopy and photography.

Fluorescent Polymer Microspheres (Aqueous)

These microspheres contain dyes incorporated into the polymer matrix during polymerisation. This produces bright fluorescent colours, minimises photobleaching and prevents dye leaching in aqueous media. They consist of crosslinked polystyrene with a specific gravity of 1.05g/cm³ and a refractive index of 1.59 @ 589nm. The aqueous suspensions contain 1% solids in a multi-component dispersing system which prevents particle aggregation.

Available particle sizes range from 30nm to 10µm for the green fluorescent microspheres, 30nm to 3.0µm for blue fluorescent microspheres and from 50nm to 2.0µm for the red. CVs range from below 20% (for the smallest particles) to less than 3%; for all particles of 200nm or greater, the CV is less than 5%.

Package quantities are 15mL or 90mL for the submicron sizes and 10mL or 60mL for the larger particles.

To download a brochure in Adobe Acrobat format giving full details of fluorescent microspheres in aqueous suspension, including individual sizes available, please click here.

Fluorescent Polymer Microspheres (Dry)

These microspheres are made of polystyrene-divinylbenzene which has a specific gravity of 1.05g/mL and a refractive index of 1.59 @ 540nm. Two fluorescent colours are available : green for 365nm UV excitation (yellow-green for violet to blue excitation) and red (emission max 612nm, excitation maximum 542nm). Mean diameters range from 6µm (CV <16%) to 165µm (CV <8%) for the green dye and 6µm to 30µm for the red. They are supplied in bottles of 1g and 5g.

To download a brochure in Adobe Acrobat format giving full details of fluorescent microspheres in dry powder form, including individual sizes available,please click here.

(CV = coefficient of variation = standard deviation as a percentage of mean diameter)

UV-Excitable Fluorescent Microspheres

Designed as a replacement for zinc cadmium sulphide particles in myocardial infarct studies, this new product (Catalogue Reference 34-1) consists of polystyrene microspheres, 1 –10µm diameter, which fluoresce a brilliant yellow-green when illuminated by UV (e.g. a hand-held Woods lamp).

Their use is described by Dr James Downey in the International Society for Heart Research website (www.ishrworld.org).

To download a brochure in Adobe Acrobat format giving full details of these microspheres, please click here.

CUSTOM DYED MICROSPHERES

If you cannot find a product to meet your specific requirements in Duke's standard range of products, then you can probably have them made to order. Virtually any of Duke's polymer microspheres can be supplied dyed with your choice from a wide range of plain and fluorescent dyes.

For further information on this service, please contact Brookhaven