Ce diaporama a bien été signalé.
Nous utilisons votre profil LinkedIn et vos données d’activité pour vous proposer des publicités personnalisées et pertinentes. Vous pouvez changer vos préférences de publicités à tout moment.

Paper Chromatography | Types of Papers Used

353 vues

Publié le

In Paper Chromatography wide variety of papers are available commercially in different sizes, shapes, porosities, thickness and chemical treatments.

Publié dans : Sciences
  • Soyez le premier à commenter

Paper Chromatography | Types of Papers Used

  1. 1. Ubaid Tariq Bhat M. Pharm (Pharmaceutical Biotechnology) Delhi Pharmaceutical Science and Research University Email: bhatubaid55@gmail.com PAPERS FOR CHROMATOGRAPHY
  2. 2. Wide variety of papers are available commercially in different sizes, shapes, porosities, thickness and chemical treatments. Types of papers A. Pure cellulose papers (Whatman papers) B. Modified cellulose papers 1. Chemically modified papers a. Carboxyl papers b. Acetylated papers 2. Impregnated papers 3. Loaded papers a. Paper loaded with adsorbent powder b. Papers loaded with Ion-Exchange celluloses c. Papers loaded with synthetic organic Ion-Exchange resins d. Papers loaded with inorganic Ion-Exchangers C. Glass fibre type papers
  3. 3. A. PURE CELLULOSE PAPER These types of papers are prepared from cotton linters selected to be especially low in organic and inorganic impurities and uniform in physical characteristics. Whatman papers have approximately the following percentage composition. components percentage α Cellulose 98-99 β Cellulose 0.3-1.0 Pentosans 0.4-0.8 Ether soluble matter 0.015-0.03 Ammonia 0.001-0.06 Organic nitrogen <0.01 Inorganic material 0.008-0.06
  4. 4. Various types of Whatman chromatography papers
  5. 5. Mostly used whatmann chromatographic filter papers are: Whatmann 31ET (coarser and faster)used for separation of substances having sufficiently wide apart Rf. Whatmann 3MM (fine paper) is generally used for preparative purposes. Whatmann 20 (slow paper) (MN 261, EDROL 208, S and S 2045, S and S 2071)  Troublesome inorganic impurities include copper and iron, which form complexes with amino acids and peptides, leading to tailing zones or multiple spots.  These interfering metal impurities are removed by washing with dilute HCl or metal complexing agent EDTA followed washing with distilled water.
  6. 6. B. MODIFIED CELLULOSE PAPERS Cellulose paper can be modified in several ways to alter its behaviour. 1. Chemically modified papers a. Carboxyl papers • The exchange capacity of the paper is increased by increasing the carboxyl content (1.4%) by partial oxidation. • Used for efficient separation of polar substances, Cationic separation of potential amines and amino acids. b. Acetylated papers • Whatmann no 1, S&S 602, ED papers are partially acetylated by treating with glacial acetic acid containing 5% of acetic anhydride.
  7. 7. • After standing at room temperature overnight the solution is then replaced by 22.5% acetic anhydride in amyl acetate and then perchloric acid is added slowly and kept on standby for 2- 3 hours. • Paper is removed, washed with cold water, rinsed with methanol and dried at room temperature. • The acetyl content is then about 26% by weight which is sufficient for separation of hydrophobic substances. • Uses: Reverse phase chromatography of lipophilic substances like steroids, insecticides, pigments and also metal cations. 2. Impregnated papers • Paper sheets are impregnated with oils to separate hydrophobic substances such as amines, lipids, steroids, vitamins, and pesticides (reverse phased chromatography)
  8. 8. 3. Loaded papers • Loaded papers consist of dispersion of powder, fibre, or resin in a normal cellulosic paper a. Paper loaded with adsorbent powder • E.g. Silica papers, alumina papers, zirconia papers, kieselguhr papers. • These papers are used to separate less polar and nonpolar substances (such as lipids, sterols, steryl esters, steroids, terpenes, dyes, insectcides, chloroplast pigments and inorganic ions. b. Papers loaded with Ion-Exchange celluloses • Chromatographic papers are coated by anionic or cationic exchangers
  9. 9.  Cellulose phosphate paper (Whatmann P 81) (bifunctional cationic exchanger)  Carboxymethylcellulose paper (Whatmann CM 82) (momofunctional cationic exchanger) Aminoethylcellulose paper (Whatmann AE 81) (monofuntional anionic exchanger) Diethylaminoethylcellulose paper (whatmann DE 81)  Ecteola cellulose paper (Whatmann ET 81)
  10. 10. c. Papers loaded with synthetic organic Ion-Exchange resins: • coated with micro pulverised ion-exchange resin incorporated into α-cellulose pulp (reeve angle papers) d. Papers loaded with inorganic Ion exchangers: e.g. zirconium phosphate, hydrous oxide, and ammonium molybdophosphate C. GLASS FIBER TYPE PAPERS •Manufactured from fine borosilicate glass fibres and can be employed with detection reagents that are too corrosive for cellulose based papers (e.g. chromic-sulphuric acid charring solution) •Also used in extreme conditions of temperature and acidity where cellulose papers are unstable.

×