Question

1.Show calculations for making following reagents

A. 500 ml of a 1M solution of Tris (molecular weight 121.1 g/mol)                                      1Pt

B. 200 ml of 0.2M EDTA (MW 372.2 g/mol)                                                                                  1Pt

C. 100 ML of TE buffer (contains 10 mM Tris and 1 mm EDTA) using A and B                  

Answer 1

Molarity = (weight of the compound/ molecular wight) x (1000/volume in mL)

From the above formula

A) weight of the tris is = 60.55 grams

B) Weight of the EDTA needed is = 14.888 grams

TE buffer is often used to store DNA and RNA.

C) for 100 mL TE buffer, 1mL of tris and 0.2 mL of EDTA diluted to 100mL (with water)

for 1 liter of 1x TE solution

volume	reagent	final conc.
10 ml	1M Tris-HCl pH 7.5 or 8.0 (see notes)	10 mM
2 ml	0.5M EDTA pH 8.0	1 mM
988 ml	ddH2O