Bromide, chloride, fluoride, nitrate, nitrite and sulfate are measured together by ion chromatography, following EPA Method 300.0 (Part A). The method applies to drinking water, groundwater, surface water and wastewater.
A small volume of the sample is injected into the ion chromatograph. The anions are separated on a guard column and an analytical column, pass through a suppressor, and are measured with a conductivity detector. Each anion is identified by its retention time and quantified against a calibration curve prepared from standards of that anion. Substances with similar retention times can overlap an anion’s peak; diluting or fortifying the sample resolves most of these interferences.
Concentrations are given in milligrams per liter (mg/L). A result describes the sample as received; on its own it does not show that water is safe to drink or that a system meets a permit or regulation.
Bromide is one of the six anions in this group. Bromate, a by-product of drinking water disinfection, is a different test (EPA Method 300.1) and is not part of this group.
EPA lists chloride among its secondary drinking water standards, which deal with aesthetic effects rather than health; the effect it names is a salty taste. Reported as the chloride ion.
Fluoride appears in both EPA’s primary drinking water standards and its secondary (aesthetic) standards. Reported as the fluoride ion.
EPA regulates nitrate in public drinking water measured as nitrogen, and lists runoff from fertilizer use, leaking septic tanks and sewage, and erosion of natural deposits as sources. EPA Method 300.0 also expresses nitrate as nitrogen (nitrate-N); a result can instead be expressed as the nitrate ion, so tell us which basis you need. Nitrate-N is about 0.226 times the same amount expressed as nitrate ion.
EPA regulates nitrite in public drinking water measured as nitrogen, with the same listed sources as nitrate. EPA Method 300.0 also expresses nitrite as nitrogen (nitrite-N); a result can instead be expressed as the nitrite ion, so tell us which basis you need. Nitrite-N is about 0.304 times the same amount expressed as nitrite ion.
EPA lists sulfate among its secondary drinking water standards; the effect it names is a salty taste. Reported as the sulfate ion.
For drinking water compliance or permit samples, tell us the program before you sample: the method has to be one that program accepts. Contact us for containers and sampling instructions before you collect the sample. Other water tests are available upon request.
The method numbers on this page follow the published EPA and Standard Methods designations. These references describe the methods; the TNI LAMS registry lists each method’s code and revision.
Questions about a sample or a method, call 360-967-7010 or email [email protected].
