Answer:
for 1 Litre(1000 ml) of 1x TBE
10.8 g Tris
5.5 g Boric acid
4 ml 0.5 M EDTA (pH 8.0)
900 ml distilled water
Adjust volume to 1 Liter.
so for 250 ml divide everything by 4
2.7 g Tris
1.37 g Boric acid
1 ml 0.5 M EDTA (pH 8.0)
225 ml distilled water
Adjust volume to 250 Ml