Is it ok to keep ph buffer solution after it's made up

Is it ok to keep ph buffer solution after it's made up from the individual sachets. I know they're cheap but it seems a waste to throw away unless it's necessary ... and I can't see how it being made up would affect it's shelf life ( considering you can buy it made up as well as in a powder ). I'd be storing it in a honey jar ( essentially a mason jar ) ... and of course washing the electrode in distilled water before immersing it in the solution

 

The problem is that the air contains CO2 and that dissolves in water to form carbonic acid which consumes some of the buffering capacity of the buffer especially for pH 10 buffer, less so for pH 7 and not very much at all for pH 4. So you can doubtless get away with storing it after preparation with pH 4, can maybe get away with it at 7 but shouldn't attempt to store pH 10 for very long at all. Of course the situation isn't any worse than if you buy the buffers pre-mixed in bottles. If you do that be very careful with pH 10. Pour out what you need quickly and recap the bottle tout suite. This problem is clearly one of the big advantages of the capsules and sachets provided you use them as intended.

 

thanks for that very informative answer

 

I find that the sachets or capsules of buffer make small batches of solution that will last when stored in sealed containers. As mentioned above, the 4 and 7 solutions are sufficiently stable to be long-lived when properly stored.