Altering pH of a luminol solution

[ChanYoung Park]

The recipe for luminol solution that I found on the internet is:
0.2g luminol, 4.0g Na₂CO₃, 24.0g NaHCO₃, 0.5g (NH₄)₂CO₃, 0.4g CuSO₄ dissolved in 1 dm³ of water.
How can I alter the pH of the solution to get a range of pH values from 7 to 14 without affecting the chemisty of the solution?

 

[Borek]

Very general answer: you can't. At some point copper hydroxide will precipitate, and the "chemistry" of the solution will change.

Less general answer: identify buffer in the solution, think how you can change its pH.

 

[ChanYoung Park]

Very general answer: you can't. At some point copper hydroxide will precipitate, and the "chemistry" of the solution will change.

Less general answer: identify buffer in the solution, think how you can change its pH.

What if I use NaOH and luminol dissolved in 1 dm³ water?

 

[Borek]

What if I use NaOH and luminol dissolved in 1 dm³ water?

Why the volume? What if you used them dissolved in 2 dm³ water?

Yes, adding NaOH will definitely change pH. But as I said earlier, you can as well change ratio of conjugates making a buffer and prepare solution of a different pH. You won't get far from the original pH this way though.