Sephadex G 50

The media used for gel exclusion chromatography include dextran (Sephadex™), polyacrylamide (Bio-Gel P™) and dextran-polyacrylamide (Sephacryl™) and agarose (Sepharose™ and BioGel A™). Each is available with a variety of different ranges of pore size in the beads, permitting separation of macromolecules of different size.
A gel with a smaller range of pore sizes (and hence a smaller range over which it can separate macromolecules on the basis of their size) will give a higher resolution; a gel with a wider range will give lower resolution, but will permit fractionation of a larger range of sizes as an initial step when the approximate molecular mass of the enzyme is not known.
The particle size of the gel beads (the mesh size) also affects resolution; smaller beads permit higher resolution, but a lower flow rate through the column (and hence a slower separation).
The table shows the useful range for the most commonly used gel filtration media - the lower and upper molecular sizes (in kDa) over which they can be used to separate macromolecules. The upper limit is known as the exclusion limit of the gel - the size above which proteins will elute in the void volume of the column.
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lower limit

upper limit



dextran gels



Sephadex G-50

1.5

30



Sephadex G-75

3

80



Sephadex G-100

4

150



Sephadex G-150

5

300



Sephadex G-200

5

600



polyacrylamide gels



Bio-Gel P-10

1.5

20



Bio-Gel P-30

2.5

40



Bio-Gel P-60

3

60



Bio-Gel P-100

5

100



Bio-Gel P-150

15

150



BioGel P-200

30

200



Bio-Gel P-300

60

400



dextran-polyacrylamide gels



Sephacryl S-200

5

250



Sephacryl S-300

10

1500



Sephacryl S-400

20

8000



agarose gels



Sepharose 6B

10

4000



Sepharose 4B

60

20,000



Sepharose 2B

70

40,000



Bio-Gel A-0.5

10

500



Bio-Gel A-1.5

10

1500



Bio-Gel A-5

10

5000



Bio-Gel A-15

40

15,000



Bio-Gel A-50

100

50,000