Microparticles made using potassium persulfate as the initiator have sulfate groups on their surface. As a result, these particles are negatively charged and are hydrophilic, as shown in equation (1). PDF Potassium Persulfate
The SPHEROTM polystyrene particles greater than 3μm are usually prepared using benzoyl peroxide as the initiator. These particles are relatively more hydrophobic, as shown in equation (2). PDF BPO
SPHEROTM polystyrene particles are composed of linear polystyrene without any cross-linking agent. These particles cannot tolerate organic solvents such as toluene, xylene, chloroform, methylene chloride, acetonitrile, dimethyl formamide or acetone. However, SPHEROTM polystyrene particles are stable in the presence of some water miscible solvents such as dimethyl sulfoxide and alcohols. Uniform size cross-linked polystyrene particles that are stable in the presence of organic solvents are also available. Uniform SPHEROTM polystyrene particles are ideal for use in immunoassays such as latex agglutination, particle based enzyme immunoassays and fluorescence immunoassays. A tight size range of SPHEROTM polystyrene particles is maintained by monitoring size using a NICOMP Laser Particle Sizer (for particles less than 3μm) and a Scanning Electron Microscope and/ or Beckman Coulter MultisizerTM 3 for larger particles. Although the size measurements are accurate, these particles are not certified for use as a calibration standard for size measurements or pore size analysis.
These polystyrene beads are used during the production of our other product lines including fluorescent, functionalized, crosslinked, magnetic, and protein coated particles. In addition, Spherotech polystyrene beads are used to manufacture a wide range of flow cytometry beads for applications, such as calibration, alignment, sensitivity measurements, compensation, and various kits for assay development.