USGS-NWQL: I-2058: Anions, dissolved, water, IONCHR

Summary
Analytes
Revision
Data and Sites

Official Method Name

Anions, ion-exchange chromatographic, low ionic-strength water, automated

Current Revision

1985

Media

WATER

Instrumentation

Ion Chromatography

Method Subcategory

Inorganic

Method Source

USGS-NWQL

Citation

Methods for the Determination of Inorganic Substances in Water and Fluvial Sediments, Techniques of Water-Resources Investigations of the United States Geological Survey, Book 5, Chapter A1 Edited by Marvin J. Fishman and Linda C. Friedman

Brief Method Summary

Chloride is determined sequentially with six other anions by ion-exchange chromatography. Ions are separated based on their affinity for the exchange sites of the resin. The separated anions in their acid form are measured using an electrical-conductivity cell. See method I-2057, anions, ion-exchange chromatographic, auto-mated, and method I-2058, anions, ion-exchange chromatographic, precipitation, automated.

Scope and Application

This method may only be used for the determination of dissolved bromide, chloride, fluoride, nitrate, orthophosphate, and sulfate in water with a specific conductance of approximately 100 uS/cm or less.
Analysis must be performed on a filtered (rinsed 0.45 um membrane filter) or particulate-free, unacidified sample.

Applicable Concentration Range

The range of the method varies by analyte; see the method for more information.

Interferences

A negative peak or dip, which is caused by a combination of water and carbonate, is seen in the chromatogram using a fiber suppressor. This interference is eliminated by adding concentrated eluent to the sample.
Because low-ionic strength samples contain low concentrations of these six anions, there will be no unresolved peaks and, therefore, no interferences.
Oxalate, acetate, or formate may interfere if present.

Quality Control Requirements

Calibrate instrument using calibration standards (CAL). Quality control samples (QCS) and laboratory blanks (LB) analyzed at a minimum of I each after every 10 samples. (Reference OFR 95-443).

Sample Handling

Container Description: 250 mL Polyethylene bottle.
Treatment and Preservation: Filter through 0.45-um filter; using filtered sample to rinse container.

Maximum Holding Time

180 days

Relative Cost

$51 to $200

Sample Preparation Methods

This method has 6 analytes associated with it.

Analyte	Detection Level	Bias	Precision	Spiking Level
Bromide(24959-67-9) Bromide Bromide (9CI) Bromide ion (-1)	0.010 mg/L	N/A	N/A
Chloride(16887-00-6) Chloride Chloride ion	0.010 mg/L	N/A	4.30 % RSD (SL)	0.23 mg/L
Fluoride(16984-48-8) Fluoride	0.010 mg/L	N/A	8.10 % RSD (SL)	0.09 mg/L
Nitrate(14797-55-8) Nitrate Nitrate ion Nitrate-N Nitrates/nitrites Nitrogen, nitrate	0.010 mg/L	N/A	7.70 % RSD (SL)	0.06 mg/L
Phosphate(14265-44-2) Orthophosphate Orthophosphate, total Phosphate Phosphorus (as phosphate) Phosphorus, phosphate, ortho Reactive phosphorus Total orthophosphate Total phosphorus	0.010 mg/L	N/A	8.80 % RSD (SL)	0.05 mg/L
Sulfate(14808-79-8) Sulfate Sulfate (as ion) Sulphate (as ion)	0.010 mg/L	N/A	2.60 % RSD (SL)	2.60 mg/L

Precision Descriptor Notes:	Precision based on analysis of a sample 10 times by a single operator.
Detection Level Note:	Minimum reporting level.

Revision	PDF/Link
1985

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USGS-NWQL: I-2058: Anions, dissolved, water, IONCHR

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