The unopened ampoules are stable for at least one year from the date of manufacture. Once the ampoule has been opened any unused concentrate should be discarded. The working standards that are made from the concentrate are subject to stability according to the laboratory’s written SOP. Most methods call for regular standardization of working stock sulfide solutions. The solutions are useable as long as they are within the acceptance criteria of the laboratory. Storing the solutions with minimum headspace at 4°C should help increase the length of time for which the solution is stable.

You receive 6 ampoules of 1.5 mL each.