Shahjalal University of Science and

Technology,

Sylhet

Department of ChemistryCourse no. : CHE 370

Course title : Computational ChemistryA presentation on gel chromatography

Submitted to,

Dr Muhammad Abul Hasnat&

Dr Ahmed Jalal Farid Us Samad

Presented by,Tanjila IslamReg No.: 2010131019Semester : 3/2

Gel chromatography

Developed by,Tanjila Islam

Reg no.: 2010131019Semester : 3/2

Principle of gel chromatography :• Gel chromatography, also known as

gel permeation chromatography(GPC), is a chromatographic technique that separates dissolved molecules on the basis of their size by pumping them through specialized columns containing a microporous packing material(gel).

Gel chromatography

Points to accentuate on :• Stationary phase is a porous polymer matrix whose

pores are completely filled with the solvent to be used as the mobile phase. • The pore size is highly critical, since the basis of the

separation is that molecules above a certain size are totally excluded from the pores, and the interior of the pores is accessible, partly or wholly, to smaller molecules.• The flow of mobile phase will cause larger

molecules to pass through the column unhindered, without penetrating the gel matrix, whereas smaller molecules will be retarded according to their penetration of the gel.

By-Tan

jila Islam

Molecules coming towards pores into gel

A simple view for GPC :

Figure 1 : Principle of gel chromatography: A) mixture applied to the top of the column; B) partial separation; C) complete separation; D)excluded substance emerges from the column. By-Tanjila Islam

Column parameters and separation :• A column is made up by pouring a slurry of swollen gel particles in

the solvent used to swell the gel into a suitable tubular container.• An equation is given below:

Vt = V0 + Vi + Vm where,

Vt = the total volume of the column (which can be measured), V0 = the volume of liquid outside the gel matrix (known also void or dead volume), Vi = the volume of liquid inside the matrix, Vm= the volume of the gel matrix,

By-Tanjila Islam

Fig : Separation parameter for GPC column

Criteria of gel :

Fig: Choice of gel

* The gel must be chemically inert, * It must be mechanically stable, * It has to be a carefully formed and reproducible porous structure, * It must contain a fairly uniform particle size.

Variety of gels : Dextran gel:• natural linear polysaccharide

containing α-1,6 link• insoluble in aqueous media • formed by cross-linking of -OH

groups of dextran and a dispersion of epichlorohydrin in an organic medium• high chemical stability

Fig : structure of dextran gel

Agarose gel :• large porous size gel• formed from the neutral fraction of agar

and the agarose units cross-linked with alternating 1,3 linked-β-D-galactose and 1,4-linked 3,6-anhydro-α-L-galactose units • formed below 30˚C• Useful for large molecule separation Fig : Polymer of agarose gel

Polyamide gel:• low solubility• used for separation of

phenols, organic acids etc• ability to form strong H-

bonds between its amide and the phenolic

-OH groups

Methodology:

Fig: Instrumentation of gel chromatography

• Column preparation • Sample preparation

Application :• Group separations and desalting• Fractionation of mixtures• Molecular weight determinations : log M = A – B(Ve/Vo)• Protein ligand binding

Fig : Group separation of haemoglobin and sodium chloride

THANK YOUBy,Tanjila Islam