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

Media

WATER

Instrumentation

Ion Chromatography

Method Subcategory

Inorganic

Method Source

EPA-OGWDW/TSC

Citation

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.

Interferences

(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.

(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 < 4^oC. 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

This method has 12 analytes associated with it.

Analyte	Detection Level	Bias	Precision	Spiking Level
Bromate(15541-45-4) Bromate	1.440 ug/L	101% Rec (SL)	8.86 % RSD (SL)	5.00 ug/L
Bromide(24959-67-9) Bromide Bromide (9CI) Bromide ion (-1)	0.014 mg/L	96% Rec (SL)	0.92 % RSD (SL)	0.50 mg/L
Chlorate(14866-68-3) Chlorate	1.310 ug/L	98% Rec (SL)	0.82 % RSD (SL)	100.00 ug/L
Chloride(16887-00-6) Chloride Chloride ion	0.004 mg/L	99% Rec (SL)	0.10 % RSD (SL)	50.00 mg/L
Chlorite(14998-27-7) Chlorite	0.890 ug/L	96% Rec (SL)	0.99 % RSD (SL)	100.00 ug/L
Fluoride(16984-48-8) Fluoride	0.009 mg/L	90% Rec (SL)	1.18 % RSD (SL)	2.00 mg/L
Methyl fluoroacetate(453-18-9) Fluoroacetic acid methyl ester Methyl fluoroacetate	N/A	N/A	N/A
Nitrate(14797-55-8) Nitrate Nitrate ion Nitrate-N Nitrates/nitrites Nitrogen, nitrate	0.008 mg/L	95% Rec (SL)	0.14 % RSD (SL)	10.00 mg/L
Nitrate/nitrite(E-10128) NO2+NO3 NO2/NO3 NO3+NO2 Nitrate + nitrite Nitrate plus nitrite Nitrate+nitrite Nitrate/nitrite Nitrite + nitrate Nitrite+nitrate	N/A	N/A	N/A
Nitrite(14797-65-0) Nitrite Nitrite (as ion) Nitrite nitrogen Nitrite-N Nitrites Nitrogen, nitrite	0.001 mg/L	85% Rec (SL)	0.51 % RSD (SL)	1.00 mg/L
Phosphate(14265-44-2) Orthophosphate Orthophosphate, total Phosphate Phosphorus (as phosphate) Phosphorus, phosphate, ortho Reactive phosphorus Total orthophosphate Total phosphorus	0.019 mg/L	96% Rec (SL)	0.14 % RSD (SL)	10.00 mg/L
Sulfate(14808-79-8) Sulfate Sulfate (as ion) Sulphate (as ion)	0.019 mg/L	90% Rec (SL)	0.11 % RSD (SL)	50.00 mg/L

Precision Descriptor Notes:	Precision and accuracy values were calculated using data from nine replicate analyses of a fortified reagent water sample. Additional precision and accuracy data, including data from different matrices, are available in the method.
Detection Level Note:	MDL procedure is equivalent to the procedure at 40 CFR part 136, Appendix B. MDLs were determined using the standard deviation of 7 replicate analyses of an analyte-fortified reagent water sample multiplied by the t-value for 6 degrees of freedom at the 99% confidence level (3.14). Detailed instructions for how MDLs are determined are found in Section 9.2.4 of the Method.

Revision	PDF/Link
Revision 1.0, 1997

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

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