Question

You are provided 1M Tris-Hcl, pH = 9.0, NaCl (MW = 58.44), and Chelex resin “beads”. Describe how you would prepare 10% Chelex in 50mM Tris-HCl, pH = 9.0. You’ll need 5ml of this solution.

Answer 1

Answer = preparation of  10% Chelex in 50mM Tris-HCl, pH = 9.0 as follows:

You are provided 1M Tris-Hcl, pH = 9.0,

first we have to prepare 50 mM Tris -HCl from 1M Tris -HCl :

C1 ( starting concentration ) = 1 M = 1000 mM

V1 = ? ml

C2 = 50 mM

V2 = 5ml

formula is :

C1 ( starting concentration ) X V1 (starting volume) = C2 (final conc.) X  V2 ( final volume)

V1 ml = C2 X V2 / C1

= 50 mM X 5 ml / 1000 mM

= 0.25 ml

therefore take 0.25 ml of 1M Tris -HCl  pH = 9.0., and dilute upto 5 ml of distilled water.we get 50mM tris-HCl of pH 9.

to prepare 10% Chelex in 50mM Tris-HCl, pH = 9.0 :

10 % means 10 gms of Chelex in 100 ml of buffer.

10 gms of chelex -------------------- 100 ml of Tris-HCl , 50 Mm buffer ----------------- 10% solution.

? gms of chelex-------------------- 5 ml of  Tris-HCl , 50 Mm buffer -------------------- 10 % solution

= 10 X 5 / 100

= 0.5 gms of chelex.

Therefore for preparation of 10 % chelex in 50 Mm Tris- HCl , pH 9 , - 5ml, weigh 0.5 gms of chelex and dilute upto 5 ml with 50 Mm Tris- HCl , pH 9