Biochemical Techniques and Instrumentation

2.2.2.1.Dextran gels

The dextran gel materials are most common support matrices available in dry powder form and commercially known as 'Sephadex'. Dextran gel is made by cross-linking a polysaccharide, dextran with epichlorohydrin. They have hydrophilic character and swells in aqueous media. They are stable in water, salt solution, organic solvents, alkali and weak acidic solution. They are easily susceptible to bacterial contamination and hence require an addition of preservative during storage. Sephadex are available as a series of beads with different separation ranges (Table 2.3.2.1).

Gel type	Fractionation range (Da)
G-10	100-800
G-15	500-1,500
G-25	1000 – 5,000
G-50	1,500 – 30,000
G-75	3,000 – 80,000
G-100	4,000 – 1,50,000
G-150	5,000 – 3,00,000
G-200	5,000 – 6,00,000