Best and most conveniently stored together with proper recognition and precaution for their individual acid or alkaline nature. Keep bottles tightly closed.
Ready-to-use Buffer Solutions' shelf life varies depending on pH value-from good to poor. The higher the pH value, the shorter the shelf life. Storage conditions vary so widely that it isn't possible to be specific about shelf life. Concentrated buffers, buffer capsules and buffers in Chemvelopes all have better long-term shelf life than standard buffers.
The pH 4, 7 and 10 buffer solutions are dyed for convenience, to allow easy identification and prevent confusion. These three buffers are the standards used to calibrate pH meters.