ASTM D4327-97
(Test Method)Standard Test Method for Anions in Water by Chemically Suppressed Ion Chromatography
Standard Test Method for Anions in Water by Chemically Suppressed Ion Chromatography
SCOPE
1.1 This test method covers the sequential determination of fluoride, chloride, nitrite, ortho -phosphate, bromide, nitrate, and sulfate ions in water by chemically suppressed ion chromatography. Note 1-Order of elution is dependent upon the column used; see Fig. 1.
1.2 This test method is applicable to drinking and waste waters. The ranges tested for this test method for each anion were as follows (measured in mg/L): Fluoride 0.26 to 8.49 Chloride 0.78 to 26.0 Nitrite-N 0.36 to 12.0 Bromide 0.63 to 21.0 Nitrate-N 0.42 to 14.0 o-Phosphate 0.69 to 23.1 Sulfate 2.85 to 95.0
1.3 It is the user's responsibility to ensure the validity of this test method for other matrices.
1.4 Concentrations as low as 0.01 mg/L were determined depending upon the anions to be quantitated, in single laboratory work. Utilizing a 50-[mu]L sample volume loop and a sensitivity of 3 [mu]S/cm full scale, the approximate detection limits shown in Table 1 can be achieved. If lower detection levels are required, the sensitivity may be improved by using a lower scale setting (100 [mu]L). The analyst must assure optimum instrument performance to maintain a stable baseline at more sensitive conductivity full-scale settings.
1.5 The upper limit of this test method is dependent upon total anion concentration and may be determined experimentally as described in Annex A1. These limits may be extended by appropriate dilution or by use of a smaller injection volume.
1.6 Using alternate separator column and eluents may permit additional anions such as formate or citrate to be determined. This is not the subject of this test method.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
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Designation: D 4327 – 97
Standard Test Method for
Anions in Water by Chemically Suppressed Ion
Chromatography
This standard is issued under the fixed designation D 4327; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the sequential determination of
fluoride, chloride, nitrite, ortho-phosphate, bromide, nitrate,
and sulfate ions in water by chemically suppressed ion chro-
matography.
NOTE 1—Order of elution is dependent upon the column used; see Fig.
1.
1.2 This test method is applicable to drinking and waste
waters. The ranges tested for this test method for each anion
were as follows (measured in mg/L):
FIG. 1 Chromatogram Showing Separation Using the AS4A
Fluoride 0.26 to 8.49
Column
Chloride 0.78 to 26.0
Nitrite-N 0.36 to 12.0
levels are required, the sensitivity may be improved by using a
Bromide 0.63 to 21.0
Nitrate-N 0.42 to 14.0
lower scale setting (<3 μS/cm) or a larger sample injection loop
o-Phosphate 0.69 to 23.1
(>100 μL). The analyst must assure optimum instrument
Sulfate 2.85 to 95.0
performance to maintain a stable baseline at more sensitive
1.3 It is the user’s responsibility to ensure the validity of this
conductivity full-scale settings.
test method for other matrices.
1.5 The upper limit of this test method is dependent upon
1.4 Concentrations as low as 0.01 mg/L were determined
total anion concentration and may be determined experimen-
depending upon the anions to be quantitated, in single labora-
tally as described in Annex A1. These limits may be extended
tory work. Utilizing a 50-μL sample volume loop and a
by appropriate dilution or by use of a smaller injection volume.
sensitivity of 3 μS/cm full scale, the approximate detection
1.6 Using alternate separator column and eluents may per-
limits shown in Table 1 can be achieved. If lower detection
mit additional anions such as formate or citrate to be deter-
mined. This is not the subject of this test method.
1.7 This standard does not purport to address all of the
This test method is under the jurisdiction of ASTM Committee D-19 on Water
safety problems, if any, associated with its use. It is the
and is the direct responsibility of Subcommittee D19.05 on Inorganic Constituents
responsibility of the user of this standard to establish appro-
in Water.
Current edition approved Oct. 15, 1991. Published February 1992. Originally
priate safety and health practices and determine the applica-
published as D 4327 – 84. Last previous edition D 4327 – 88.
bility of regulatory limitations prior to use.
The following references may be consulted for additional information:
Small, H., Stevens, T. S., and Bauman, W. C., “Novel Ion Exchange Chromato-
TABLE 1 Approximate Single Laboratory Detection Limits in
A,B
graphic Method Using Conductrimetric Detection,” Analytical Chemistry, Vol 47,
Reagent Water
1975, p. 1801.
Retention MDL
Stevens, T. S., Turkelson, V. T., and Alve, W. R., “Determination of Anions in
Analyte Peak No.
Time, min mg/L
Boiler Blow Down Water with Ion Chromatography,” Analytical Chemistry, Vol 49,
1977, p. 1176.
Fluoride 1 1.2 0.01
Sawicki, E., Mulik, J. D., and Witgenstein, E., Editors, Ion Chromatographic Chloride 2 1.7 0.02
Analysis of Environmental Pollutants, Ann Arbor Science Publishers, Ann Arbor, Nitrite-N 3 2.0 0.004
MI, 1978.
Bromide 4 2.9 0.01
Mulik, J. D., and Sawicki, E., Editors, Ion Chromatographic Analysis of Nitrate-N 5 3.2 0.002
Environmental Pollutants, Vol/No. 2, Ann Arbor Science Publishers, Ann Arbor, MI, o-Phosphate 6 5.4 0.003
Sulfate 7 6.9 0.02
1979.
Weiss, J., Handbook of Ion Chromatography, Dionex Corp., Sunnyvale, CA, A
Data provided by US EPA/EMSL Laboratory, Cincinnati, OH.
1986. B
Column: as specified in 7.1.4.
Waters Innovative Methods for Anion Analysis, Waters Chromatography Division
Detector: as specified in 7.1.6.
of Millipore, Method A 107 and A 116, 1990.
Eluent: as specified in 8.3.
Haddad, P. R., and Jackson, P. E., Ion Chromatography: Principles and
Pump rate: 2.0 mL/min.
Applications, Elsevier Scientific Publishing Co., 1990. Sample loop: 50 μL.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 4327
2. Referenced Documents 5. Significance and Use
2.1 ASTM Standards: 5.1 Ion chromatography provides for both qualitative and
− −
D 1066 Practice for Sampling Steam quantitative determination of seven common anions, F ,Cl ,
3 − −2 − − −2
D 1129 Terminology Relating to Water NO , HPO ,Br ,NO , and SO , in the milligram per
2 4 3 4
D 1193 Specification for Reagent Water litre range from a single analytical operation requiring only a
D 2777 Practice for Determination of Precision and Bias of few millilitres of sample and taking approximately 10 to 15
Applicable Methods of Committee D-19 on Water min for completion.
D 3370 Practices for Sampling Water from Closed Con-
NOTE 2—This test method may be used to determine fluoride if its peak
duits
is in the water dip by adding one mL of eluent (at 1003 the concentration
in 8.3) to all 100-mL volumes of samples and standards to negate the
3. Terminology
effect of the water dip. (See 6.3, and also see 6.4.) The quantitation of
3.1 Definitions—For definitions of terms used in this test unretained peaks should be avoided. Anions such as low molecular weight
organic acids (formate, acetate, propionate, etc.) which are conductive
method, refer to Terminology D 1129.
coelute with fluoride and would bias fluoride quantitation in some
3.2 Definitions of Terms Specific to This Standard:
drinking waters and most waste waters.
3.2.1 analytical columns—a combination of one or more
− − − −
5.2 Anion combinations such as Cl /Br and NO /NO ,
guard columns followed by one or more separator columns
2 3
which may be difficult to distinguish by other analytical
used to separate the ions of interest. It should be remembered
methods, are readily separated by ion chromatography.
that all of the columns in series contribute to the overall
capacity of the analytical column set.
6. Interferences
3.2.2 chemical suppressor device—a device that is placed
between the analytical columns and the detector. Its purpose is 6.1 Since chloride and nitrite elute very close together, they
are potential interferents for each other. It is advisable not to
to inhibit detector response to the ionic constituents in the
eluent, so as to lower the detector background and at the same have one of these anions present in a ten-fold excess over the
− −
other; that is, Cl /NO ratios higher than 1:10 or 10:1 if both
time enhance detector response to the ions of interest.
3.2.3 eluent—the ionic mobile phase used to transport the ions are to be quantitated.
6.2 As with other types of chromatography, if one of the
sample through the system.
3.2.4 guard column—a column used before the separator sample components is present at very high levels, it may
interfere by causing a very large peak on the chromatogram
column to protect it from contaminants, such as particulate
matter or irreversibly retained materials. which could mask other peaks present. This type of interfer-
ence is normally minimized by dilution of the sample (see
3.2.5 ion chromatography—a form of liquid chromatogra-
phy in which ionic constituents are separated by ion exchange Annex A1) and in some instances may be corrected if the
concentration of that anion is of interest. However, care should
followed by a suitable detection means.
be taken not to dilute the analyte concentration below its
3.2.6 resolution—the ability of an analytical column to
detectable limit.
separate constituents under specific test conditions.
6.3 Water from the sample injection will cause a negative
3.2.7 separator column—the ion exchange column used to
peak or dip in the chromatogram when it elutes, because its
separate the ions of interest according to their retention
conductivity is less than that of the suppressed eluent. This dip
characteristics prior to their detection.
−
usually occurs before Cl . Any peak of interest eluting near the
4. Summary of Test Method
water dip must be sufficiently resolved from the dip to be
4.1 An aliquot of sample is injected into an ion chromato- accurately quantitated. Some suggested techniques for elimi-
graph. The sample is pumped through two columns and a nation of the water dip are described in Appendix X1.
suppressor device and into a conductivity detector. The ana- 6.4 Due to the effect of the water dip and the interference of
lytical column and the guard column are packed with low- organic acids and due to the presence of carbonate ions in the
capacity anion exchanger. Ions are separated based on their separator column, the user of this test method is urged to use
affinity for the exchange sites of the resin. The suppressor caution when determining fluoride (see Note 2). If the user
device contains a fiber or membrane based cation exchanger wishes to be certain of good results and has interfering anions
which is continuously regenerated by a flow of dilute sulfuric present when determining fluoride, the eluent can be diluted
acid. The suppressor device reduces the background conduc- until separation of fluoride and carbonate is accomplished. This
tivity of the eluent to a low or negligible level by replacing the will cause an increase in retention time for anions such as
cations with the hydrogen ion, thereby converting the anions in sulfate to elute.
the sample to their corresponding acids. The separated anions
7. Apparatus
in their acid form are measured using an electrical-conductivity
cell. Anions are identified based on their retention times
7.1 Ion Chromatograph—The ion chromatograph should
compared to known standards. Quantitation is accomplished by have the following components assembled, as shown in Fig. 2:
measuring the peak height or area and comparing it to a
calibration curve generated from known standards.
Available from Dionex Corp., 1228 Titan Way, Sunnyvale, CA 94086. An
equivalent may be used. Other manufacturers’ components may provide equivalent
Annual Book of ASTM Standards, Vol 11.01. data.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 4327
response. The chromatogram in Fig. 1 uses a 100-μL size
sample loop.
7.1.9.1 When injections of volumes larger than the sample
loop size are made, any volume above the sample loop size
goes to waste. It is considered good technique to flush the
sample loop upon injection by injecting 2 to 3 times the sample
loop volume.
8. Reagents
8.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that
all reagents shall conform to the specifications of the Commit-
tee on Analytical Reagents of the American Chemical Society,
where such specifications are available. Other grades may be
used, provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
accuracy of the determination.
8.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean reagent water conforming
to Specification D 1193, Type II. Column life may be extended
by passing Type II water through a 0.22-μm filter prior to use.
FIG. 2 Schematic of an Ion Chromatograph Freshly prepared water should be used for making the stan-
dards intended for calibration. The detection limits of this test
method will be limited by the purity of the water and reagents
7.1.1 Eluent and Regenerant Containers.
used to make the standards. The purity of the water may be
7.1.2 Eluent Pump, capable of delivering 1 to 3 mL/min of
checked by use of this test method. Anion concentrations of
eluent at a pressure of up to 2000 psig.
less than 0.2 μg/L each are typical of this type of water.
7.1.3 Guard Column—Anion exchange column, typically of
8.3 Eluent—Dissolve 0.2856 g of sodium bicarbonate (1.7
the same anion exchange material used in the separator
mM) and 0.3816 g of sodium carbonate (1.8 mM) in water and
column. The purpose of this column is to protect the analytical
dilute to 2 L with water. Other eluents may also prove to be
column from particulate matter and irreversibly retained ma-
acceptable, provided they give the proper resolution between
terials.
the component peaks. This eluent will act as a growth media
7.1.4 Analytical Column—Anion exchange column capable
for algae. For this reason the eluent should not be kept for
of separating chloride from the injection void volume, as well
longer than one month.
as resolving the anions chloride through sulfate.
NOTE 4—Use of other eluents may change the order of elution of the
NOTE 3—Any analytical column may be used. However, the user
anions from that using the carbonate-bicarbonate eluent.
should be able to achieve the resolution and separation as shown in Fig.
8.4 Fiber or Membrane Suppressor Regenerant Solution—
1.
Cautiously add 3 mL of H SO (sp gr 1.84) to 4 L of water.
2 4
7.1.5 Suppressor Device—A fiber or membrane based cat-
8.5 Stock Solutions:
ion exchanger which is continuously regenerated by a flow of
−
8.5.1 Bromide Stock Solution (1.00 mL 5 1.00 mg Br )—
dilute sulfuric acid.
Dry approximately2gof sodium bromide (NaBr) for6hat
7.1.6 Detector—A low-volume, flow through, temperature-
150°C and cool in a desiccator. Dissolve 1.2877 g of the dried
compensated electrical conductivity cell equipped with a meter
salt in water and dilute to 1 L with water.
capable of reading from 0 to 1000 μS/cm on a linear scale.
−
8.5.2 Chloride Stock Solution (1.00 mL 5 1.00 mg Cl )—
7.1.7 Recorder, Integrator, Computer—A device compatible
Dry sodium chloride (NaCl) for1hat 100°C and cool in a
with the detector output capable of recording detector response
desiccator. Dissolve 1.648 g of the dry salt in water and dilute
as a function of time for the purpose of measuring peak height
to 1 L with water.
or area.
−
8.5.3 Fluoride Stock Solution (1.00 mL 5 1.00 mg F )—
7.1.8 Data System—An electronic integrator, such as is used
Dissolve 2.210 g of sodium fluoride (NaF) in water and dilute
with gas and liquid chromatographs, may be used to quantitate
to 1 L with water.
peak area, as well as peak height. The peak area data can be
−
8.5.4 Nitrate Stock Solution (1.0
...
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