Total Organic Carbon
The organic carbon in water and wastewater consists of multiple organic compounds in various oxidation
states. Some of these compounds can be oxidized further via biological or chemical processes. Total orga
nic carbon (TOC) is a more convenient and direct expression of total organic content than BOD, AOC, or
COD but does not provide the same kind of information.
True Color
Color is determined by visual comparison of the sample with known concentrations of colored solutions. T
he color value of water is extremely pH-dependent and invariably increases as the pH of the water is raise
d. When reporting a color value, specify the pH at which color is in solution. In some waters and wastewat
ers, apparent color is contributed principally by colloidal or suspended material.
Ion Chromatography
Ion chromatography is used for water chemistry analysis. Ion chromatographs are able to measure conce
ntrations of major anions, such as fluoride, chloride, nitrate, nitrite, and sulfate, as well as major cations s
uch as lithium, sodium, ammonium, potassium, calcium, and magnesium in the parts-per-billion (ppb) ran
ge. Concentrations of organic acids can also be measured through ion chromatography.
Some typical applications of ion chromatography include:
• Drinking water analysis for pollution and other constituents
• Determination of water chemistries in aquatic ecosystems
• Determination of sugar and salt content in foods
• Isolation of select proteins