Standard Methods: 4110B: Anions in Water by Ion Chromatography

Summary
Analytes
Revisions
Data and Sites

Official Method Name

4110 B. Ion Chromatography with Chemical Suppression of Eluent Conductivity

Current Revision

Standard Methods Online

Media

WATER

Instrumentation

Ion Chromatography

Method Subcategory

Inorganic

Method Source

Standard Methods

Citation

Standard Methods Online - Standard Methods for the Examination of Water and Wastewater

Brief Method Summary

A water sample is injected into a stream of eluent and passed through a series of ion exchangers. The anions of interest are separated on the basis of their relative affinities for a low-capacity, strongly basic anion exchanger (guard and analytical columns). The separated anions are directed through a suppressor device that provides continuous suppression of eluent conductivity and enhances analyte response. In the suppressor the separated anions are converted to their highly conductive acid forms while the conductivity of the eluent is greatly decreased. The separated anions in their acid forms are measured by conductivity. They are identified on the basis of retention time as compared to standards. Quantitation is by measurement of peak area or peak height.

Scope and Application

This method is applicable, after filtration to remove particles larger than 0.45 um, to surface, ground, and wastewaters as well as drinking water. Some industrial process waters, such as boiler water and cooling water, also may be analyzed by this method.

Applicable Concentration Range

Interferences

Any substance that has a retention time coinciding with that of any anion to be determined and produces a detector response will interfere. Low-molecular-weight organic acids, bromate, and chlorite may interfere with the determination of chloride and fluoride. A high concentration of any one ion also interferes with the resolution, and sometimes retention, of others. Sample dilution or gradient elution overcome many interferences. Modifications such as preconcentration of samples, gradient elution, or reinjection of portions of the eluted sample may alleviate some interferences but require individual validation for precision and bias and are beyond the scope of this method.

Quality Control Requirements

See Section 4020 Quality Assurance/Quality Control for minimum QC guidelines. Preferably check recovery daily at reporting level using a reporting-level standard. Recovery should be between 75 and 125%. Alternate analysis of mid-range and high-range check standards after each 10 samples. Recovery should be between 90 and 110%. If the results are to be used for environmental compliance monitoring, document precision and accuracy of the method by the analysis of four replicates of a mid-range calibration standard and calculation of the average percent recovery, and the standard deviation of the recoveries, for each analyte. Additional QC may be required for regulatory purposes.

Sample Handling

See Section 1060 Collection and Preservation of Samples under the individual analytes determined.

Maximum Holding Time

See Section 1060 Collection and Preservation of Samples

Relative Cost

$51 to $200

Sample Preparation Methods

This method has 8 analytes associated with it.

Analyte	Detection Level	Bias	Precision	Spiking Level
Bromide(24959-67-9) Bromide Bromide (9CI) Bromide ion (-1)	0.014 mg/L	102% Rec (SL)	3.00 % RSD (SL)	0.30 mg/L
Chloride(16887-00-6) Chloride Chloride ion	0.004 mg/L	104% Rec (SL)	4.50 % RSD (SL)	25.00 mg/L
Fluoride(16984-48-8) Fluoride	0.002 mg/L	N/A	N/A
Nitrate(14797-55-8) Nitrate Nitrate ion Nitrate-N Nitrates/nitrites Nitrogen, nitrate	0.003 mg/L	106% Rec (SL)	2.60 % RSD (SL)	2.50 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	0.004 mg/L	97% Rec (SL)	4.00 % 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	0.014 mg/L	101% Rec (SL)	4.00 % RSD (SL)	10.00 mg/L
Sulfate(14808-79-8) Sulfate Sulfate (as ion) Sulphate (as ion)	0.018 mg/L	105% Rec (SL)	4.00 % RSD (SL)	50.00 mg/L

Precision Descriptor Notes:	Data in NEMI are taken from a table in the method showing single-laboratory recoveries for laboratory-fortified blanks (LFB) -- 30 sets of samples analyzed over a two month period. Additional performance data in raw and finshed waters can be found in the method. Also, multi-laboratory data from a joint validation study with EPA and ASTM using older columns and hardware can be found in the 20th Edition of Standard Methods.
Detection Level Note:	The detection level of an anion is a function of sample size. A table in the method presents detection levels obtained for reagent water with a 25-uL sample loop. Detection levels in natural waters may be substantially higher because of the presence of high levels of some of the anions.

Precision Descriptor Notes:

Data in NEMI are taken from a table in the method showing single-laboratory recoveries for laboratory-fortified blanks (LFB) -- 30 sets of samples analyzed over a two month period. Additional performance data in raw and finshed waters can be found in the method. Also, multi-laboratory data from a joint validation study with EPA and ASTM using older columns and hardware can be found in the 20th Edition of Standard Methods.

Detection Level Note:

The detection level of an anion is a function of sample size. A table in the method presents detection levels obtained for reagent water with a 25-uL sample loop. Detection levels in natural waters may be substantially higher because of the presence of high levels of some of the anions.

Revision	PDF/Link
Standard Methods Online
Standard Methods 18th Edition (1992)
Standard Methods 19th Edition (1995)
Standard Methods 18th, 19th, 20th ed.

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Standard Methods: 4110B: Anions in Water by Ion Chromatography

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