Hi!

I am trying to regenerate my Ni-NTA column, and as you can see from the picture, there are 3 resins: two in the back are in darker green; one in the front is light blue.

The light blue one is the fresh resin. Two in the back is after recharge.

I am wondering why the color is so different?

And the regenerating protocol I am using is:

1. 10CV of 500mM NaCl, 50mM EDTA pH 8, 0.02% NaN3

2. 10CV water

3. 10CV 100mM NiSO4 in water

4. 10CV water

5. 10CV 500mM NaCl, 0.02% NaN3

6. 10CV water

7. Store column in 0.02% NaN3