text: To ensure consistency and repeatability, the methods use in the chemical analysis of water samples are often agreed and published at a national or state level. By convention these are often referred to as "Blue book"s.
  Certain analyses are performed in-field (e.g. pH, specific conductance) while others involve sampling and laboratory testing.
  The methods defined in the relevant standards can be broadly classified as:
  * Conventional wet chemistry including the Winkler method for dissolved oxygen, precipitation, filtration for solids, acidification, neutralisation, titration etc. Colourimetric methods such as MBAS assay which indicates anionic surfactants in water and on site comparator methods to determine chlorine and chloramines. Nephelometers are used to measure solids concentrations as turbidity. These methods are generally robust and well tried and inexpensive, giving a reasonable degree of accuracy at modest sensitivity.
  *Electro chemistry including pH, conductivity and dissolved oxygen using oxygen electrode. These methods yield accurate and precise results using electronic equipment capable of feeding results directly into a laboratory data management system
  *Spectrophotometry is used particularly for metallic elements in solution producing results with very high sensitivity, but which may require some sample preparation prior to analysis and may also need specialised sampling methods to avoid sample deterioration in transit.
  *Chromatography is used for many organic species which are volatile or which can yield a characteristic volatile component of after initial chemical processing.
  *Ion chromatography is a sensitive and stable technique that can measure lithium, ammonium NH and many other low molecular weight ions using ion exchange technology.
  *Gas chromatography can be used to determine methane, carbon dioxide, cyanide, oxygen, nitrogen and many other volatile components at reasonable sensitivities.
  *Mass spectrometry is used where very high sensitivity is required and is sometimes used  as a back-end process after gas liquid chromatography for detecting trace organic chemicals.
  Depending on the components, different methods are applied to determine the quantities or ratios of the components. While some methods can be performed with standard laboratory equipment, others require advanced devices, such as inductively coupled plasma mass spectrometry (ICP-MS).