Reliable analytical measurements of environmental samples are the
next essential ingredient, after sampling, in making sound decisions
about safeguarding public health and improving the quality of the
The development of analytical methods bgan in the late 1800s to
support water purification, commerce and agriculture. Today, the
EPA provides the analytical methods for compounds of interest under
the different regulations.
- List of Lists-A Catalogue of Analytes and Methods, US
EPA Office of Water
- Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020
- Test Methodds for Evaluating Solid Waste, 3rd edition,
- Contract Laboratory Program (CLP) Methods
spectrophotometry measures the interaction of electromagnetic radiation with matter. Often used for drinking water and wastewater.
Electrode Methods: The determination of Ph and fluoride
are examples of electrode methods. The potential (voltage) from
an electrode sensitive to the material of interest is measured against
a standard potential. Often used for drinking water and wastewater.
Gravimetric Methods: Examples of gravimetric analyses are
the Total Residue Method and the Oil and Grease Method. Gravimetric
methods require weighing small amounts of the material of interest
on a sensitive laboratory balance. Often used for drinking water
Titrimetric Methods: Titrimetric methods of analysis require
dispensing accurately measured volumes of reagents of known concentration.
At the "end point" of a titrimentric analysis, the added reagent
exactly balances the concentration of the material of interest.
Often used for drinking water and wastewater.
Gas Chromatography: Volatile compounds may be gases at standard
conditions or liquids or solids that can be converted to vapor by
heat. Environmental samples of water, soil, or waste can be sampled
with gas chromatography. Gas chromatography provides a pictorial
record of the separated sample components. Results are both qualitative
(what is present) as well as quantitative (how much is present).
Often used for volatile compounds.
Mass Spectrometry: An analytical technique used for to identifiy
and quanitfy compounds. This technique can also be used to determine
the molecualr structure of the compound. A mass spectrometer is
used to produce ions from from the compound which are then seperated
according to their charge-to-mass ratios (m/z, or mass/intensity)
Liquid Chromatography: A technique for seperating a mixture
of components. The technique involves two phases: a liquid mobile
phase and a stationary phase, usually a solid. The components of
the liquid pass through the solid at different speeds and, thus,
Units of Measure
Measurements are obtained from anlaytical laboratories and from
field instruments. Common examples for chemical concentrations are