To insure that drinking water during the Apollo missions did not become contaminated with microorganisms, chemical disinfectants were periodically injected into the water supply by the astronauts. A chlorine solution was used for the Command Module. The chlorine (sodium hypochlorite diluted to 1860 mg/L) was contained in 20 cc cylindrical ampules, like this one. Twenty minutes before water was consumed, the ampule was inserted into the water tank. Immediately afterward, a second ampule, containing a buffer (sodium dihydrogen phosphate) was inserted to neutralize the pH of the water, with and inhibitor, sodium nitrate (to slow corrosion). After waiting the 20 additional minutes for the chemicals to disperse throughout the tank, the water was potable.
This ampule was flown on Apollo 11 Command Module and was returned unused. NASA transferred it to the Smithsonian along with the rest of the contents of the Command Module in 1970.
Transferred from the NASA - Johnson Space Center