ABSTRACT
Accurate determinations of the numerous parameters and components in water samples are essential in many research programs. Nevertheless, no matter how accurate and sensitive the analytical devices and techniques applied during the analysis, the data will be useless unless special attention is given to counteracting the potential changes proceeding within a sample. A large number of substances contained in water can be expected to undergo various chemical, physical, and biological transformations. Such processes can alter the sample composition and consequently lead to unrepresentative results. Sample preservation is therefore necessary in order to inhibit reactions in the sample during the period between sampling and analysis. Unfortunately, analysis of water samples at the point of sample collection is often not possible, so sample preservation is imperative. A wide variety of techniques are therefore applied to minimize loss of target compounds from water samples during the sample holding time (Figure 2.1).
