Alkalinity water sample should be collected in 250 ml or greater volume in glass or polyethylene bottles. Since alkalinity is susceptible ot change between the time of collection and the time of analysis, the titration should be performes within a few hours of collection. The sample must be sealed from exposure ti the atmosphere. The main problem encountered when holding the sample for extended periods of time is the loss of free carbon dioxide which results in a conversion of bicarbonate to carbonate ion.