Sampling for chemical analyses see also

The choice of bottle material and bottle size to suit the intended purpose of the analysis is important. The concentration of any disinfectants such as chlorine, chlorine dioxide or ozone must be measured immediately after sampling. 

Variable components e.g. Fe , H2S or HS , phenols, cyanides, etc. must be fixed at the place of sampling. O2 and CO2 must be measured at the time of sampling. 

For other measures see the special section on water preservation (1.7). 

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