Hi all,

This post is about sophisticating a bit further the process of extraction by playing a bit further (or controlling more precisely) the pH values of a solution. The idea for this post was sparked by Phlux's comments in this post where he wanted some careful pH values for differential precipitation of harmine and harmaline.

What I am talking about is buffers; some background about what a buffer is can be found in this topic/post. As a general definition however, a buffer is a special formulation of elements (salts, bases, acids) that resists to pH changes when acids and/or bases are added into it.

There is a fairly simple recipe for making buffered solutions just by using sodium bicarbonate (baking soda) and sodium carbonate (washing soda) mixed in various ratios. The recipe is as follows:

Dissolve 10.6 grams of sodium carbonate in 1 litre of water. Call this Solution A
Dissolve 8.4 grams of sodium bicarbonate in 1 litre of water. Call this Solution B

Now mix the Solutions A and B in various proportions (as shown in the table below) to achieve a desired pH value. The achieved pH value will be stable to small additions of bases or acids. Note that the pH value is dependent on the temperature.

Solution A | Solution B | pH@20 C | pH@37 C |
______________________________________
.......1........| .......9........| ....9.14....| ....8.77.....|
.......2........| .......8........| ....9.40....| ....9.12.....|
.......3........| .......7........| ....9.51....| ....9.40.....|
.......4........| .......6........| ....9.78....| ....9.50.....|
.......5........| .......5........| ....9.90....| ....9.72.....|
.......6........| .......4........| ...10.14...| ....9.90.....|
.......7........| .......3........| ...10.28...| ...10.08....|
.......8........| .......2........| ...10.53...| ...10.28....|
.......9........| .......1........| ...10.83...| ...10.57....|

For instance, if one wants to male a basic solution that maintains its pH at around 9.4 at room temperature, then he mixes 2 parts of solution A and 8 parts of solution B. For example, 20ml of Solution A and 80ml of Solution B.

Using buffered solutions is advantageous when one is dealing with molecules that are sensitive to extreme pH values like psilocin and when one is worried about the accuracy of his pH meter.

Credits for the table goes to the attached reference paper.