Category Archives: Chemicals

Ficoll 400


Synonyms: Ficoll 400, Polysucrose-400, Ficoll PM 400
CAS Number: 26873-85-8
Chemical structure: (C12H20O10)n
Molecular Weight: ≈400,000

Appearance: White to yellowish powder

  • Ficoll 400 is high molecular weight non-ionic, highly branched, a synthetic polymer of sucrose. It is synthesized by the copolymerization of sucrose and epichlorohydrin.
  • Ficoll 400 is hydrophilic. It dissolves readily in water due to the high content of hydroxyl groups. Depending on the concentration, It forms clear to slightly hazy, colorless to yellowish solution in water.
  • The aqueous solution of Ficoll 400 is stable at alkaline and neutral pH but rapidly hydrolyzed at pH below 3.0, particularly at elevated temperatures.
  • Comparatively low osmolality and low membrane permeability make Ficoll 400 a better choice than sucrose for biological applications particularly for the separation of cells.


  • Isolation and purification of cells, cell membranes, cell organelles and viruses.
  • Denhardt’s solution, which is used for Northern and Southern hybridization, contains Ficoll 400.
  • Ficoll 400 can also be used as a high density agent for the preparation of DNA/RNA loading dye for agarose and polyacrylamide gel electrophoresis of DNA/RNA

Ethylenediaminetetraacetic acid (EDTA)

  • EDTA is a polyamino carboxylic acid. It is a colourless, water soluble solid. It’s conjugate base is named ethylenediaminetetraacetate.
  • EDTA is best known for its chelating property. It sequesters metal ions such as Ca2+ and Fe3+.
  • Most applications of EDTA rely on its ability to chelate metal ions. After being bound by EDTA, metal ions remain in solution but exhibit diminished reactivity. Metal ions are necessary for the action of many enzymes including DNases.
  • In molecular biology laboratories, EDTA is used for the preparation of many solutions including TAE, TBE, DNA loading dye, resuspension buffer (isolation of plasmid), Tris-EDTA, Trypsin-EDTA, etc.
  • It has been widely used in domestic products like food preservative and cosmetic stabilizer. It is also used extensively to dissolve limescale. Our daily use products like personal care, skin care, processed foods, cosmetic preparations and cleaning products often contains EDTA. It has extensive medical, engineering, agricultural and industrial applications as well.
  • EDTA applications in medical science (chelation therapy)
    • Eye drops containing EDTA are used to treat calcium deposits in the eye.
    • EDTA is sometimes used as an ointment for skin irritations produced by metals such as chromium, nickel, and copper.
    • EDTA is also used to treat lead poisoning or heavy metal toxicity.


  • Research in past three decades has established agarose as a useful matrix for number of biochemical techniques including gel electrophoresis, chromatography and support matrix to immobilize enzymes and cells.
  • These techniques utilize agarose for various molecular biology and biochemistry applications including nucleic acid analysis and purification, protein analysis and purification, immunodiffusion, gel filtration of viruses and sub-cellular particles, etc.
  • In addition, agarose can be used to culture cells. It can also be used in place of agar to prepare bacterial culture medium and also for animal cell culture (e.g., soft agar assay).
  • Agarose is available in a variety of form, which differ in physical properties.
  • Suitability of agarose for an application depends on its properties. The following parameters are considered while choosing agarose for an application:
    • Purity of agarose (mostly defined as the presence of sulfate content)
    • b. Melting/gelling point of agarose
    • c. Gel strength of gel
    • d. Electroendosmosis (EEO)
  • Lower grade agarose may be contaminated with other polysaccharides, as well as salts and proteins and often have high EEO, making them unsuitable for sensitive assays.
  • Although, ultra purified agarose are better choice for most assay, but they are costly which restrict their use.
  • Often the quality of agarose, their suitability for different assay are described in suppliers catalog, which can be used as a reference to chose an agarose for a particular application.