Simply dissolve the contents of a Chemvelope in 500 mL of distilled water to make a precise buffer solution.

Simply dissolve the contents of a Chemvelope in 500 mL of distilled water to make a precise buffer solution. Carton of 5 envelopes includes 1 vial of preservative solution. Powders keep 5 years; prepared solutions keep 3 weeks (or 3 months with preservative added). Preservative contains a pH indicator and colors each buffer solution for easy identification.