EPA-OGWDW/TSC: 300.1:  Anions in Water by IC

  • Summary
  • Analytes
  • Revision
  • Data and Sites
Official Method Name
Determination of Inorganic Anions in Drinking Water by Ion Chromatography
Current Revision
Revision 1.0, 1997
Ion Chromatography
Method Subcategory
Method Source
  Methods for the Determination of Organic and Inorganic Compounds in Drinking Water, Volume 1 (EPA/815-R-00-014)
Brief Method Summary
The concentration of anions in a 10-uL (for common anions) or 50-uL (for disinfection byproducts) sample are determined using an ion chromatography (IC) system equipped with a conductivity detector (CD).
Scope and Application
This method determines certain inorganic anions (both common and disinfection byproducts) in reagent water, surface water, ground water, and finished drinking water. Methyl fluoroacetate is measured using the fluoride ion.
Applicable Concentration Range
Linear calibration range (LCR) should be established by the analyst.

(A) Co-elution: Modifying the eluent with organic solvents, changing the detection system, or pretreating the sample can reduce co-elution.

(B) Pretreatment cartridges: Use of a pretreatment cartridge can lead to artifacts in the sample; use with caution.

(C) Turbidity: Remove turbidity using filtration.

(D) Weakly-bound anions: Anions which are weakly retained by the column interfere with fluoride determination at > 1.5 mg/L.

(E) Carryover effects: There are some compounds in ozonated and chlorine dioxide matrices which will elute well after sulfate. These may carry over in later runs.

(F) Chlorine dioxide. Chlorine dioxide can form chlorite. Remove chlorine dioxide by purging the sample with inert gas.

Quality Control Requirements
Initial demonstration of laboratory performance and subsequent analysis in each analysis batch of a Laboratory Reagent Blank (LRB), Laboratory Fortified Blank (LFB), Instrument Performance Check Standard (IPC), Calibration Check Standards, Laboratory Fortified Sample Matrices (LFM), and either Field, Laboratory or LFM duplicate sample analyses.
Sample Handling
Samples should be collected in plastic or glass bottles that have been thoroughly cleaned and rinsed with reagent water. Sample bottles used for chlorite analysis must be opaque or amber. Preserve samples to be analyzed for bromate, chlorate, and chlorite with 50 mg/L of ethylene diamine (EDA). Samples analyzed for nitrate-N, nitrite-N, ortho-Phosphate-P, sulfate, and chlorite should be stored at < 4oC. When collecting a field sample from a treatment plant employing chlorine dioxide, the field sample must be sparged with an inert gas (helium, argon, nitrogen) prior to the addition of EDA preservative.
Maximum Holding Time
28 days for bromide, chloride, fluoride, bromate, and chlorate
14 days for chlorite
48 hours for Nitrate-N, Nitrite-N, and ortho-Phosphate-P
Relative Cost
$51 to $200
Sample Preparation Methods