ASTM D5542-94(1999)e1
(Test Method)Standard Test Methods for Trace Anions in High Purity Water by Ion Chromatography
Standard Test Methods for Trace Anions in High Purity Water by Ion Chromatography
SCOPE
1.1 These test methods cover the determination of trace ([mu]g/L) levels of fluoride, acetate, formate, chloride, phosphate, and sulfate in high purity water using ion chromatography in combination with sample preconcentration. Other anions, such as bromide, nitrite, nitrate, sulfite, and iodide can be determined by this method. However, since they are rarely present in significant concentrations in high purity water, they are not included in this test method. Two test methods are presented and their ranges of application, as determined by a collaborative study, are as follows:
1.2 It is the user's responsibility to ensure the validity of these test methods for waters of untested matrices.
1.3 The common practical range of Test Method A is as follows: chloride, 1 to 100 [mu]g/L, phosphate, 3 to 100 [mu]g/L, and sulfate, 2 to 100 [mu]g/L.
1.4 The common practical range of Test Method B is as follows: fluoride, 1 to 100 [mu]g/L, acetate, 10 to 200 [mu]g/L, and formate, 5 to 200 [mu]g/L.
1.5 The values stated in SI units are to be regarded as the standard.
1.6 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.
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An American National Standard
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Designation: D 5542 – 94 (Reapproved 1999)
Standard Test Methods for
Trace Anions in High Purity Water by Ion Chromatography
This standard is issued under the fixed designation D 5542; 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.
e NOTE—A footnote was editorially removed in June 1999.
1. Scope priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1 These test methods cover the determination of trace
(μg/L) levels of fluoride, acetate, formate, chloride, phosphate,
2. Referenced Documents
and sulfate in high purity water using ion chromatography in
2.1 ASTM Standards:
combination with sample preconcentration. Other anions, such
D 1066 Practice for Sampling Steam
as bromide, nitrite, nitrate, sulfite, and iodide can be deter-
D 1129 Terminology Relating to Water
mined by this method. However, since they are rarely present
D 1192 Specification for Equipment for Sampling Water
in significant concentrations in high purity water, they are not
and Steam in Closed Conduits
included in this test method. Two test methods are presented
D 1193 Specification for Reagent Water
and their ranges of application, as determined by a collabora-
D 2777 Practice for Determination of Precision and Bias of
tive study, are as follows:
Applicable Methods of Committee D-19 on Water
Limit of Detection
D 3370 Practices for Sampling Water from Closed Con-
Range Tested (Single Operator)
(μg/L Added) (μg/L) Sections
duits
Test Method A: 7–15
D 4327 Test Method for Anions in Water by Chemically
Chloride 0–24 0.8
Suppressed Ion Chromatography
Phosphate 0–39
Sulfate 0–55 1.8
D 4453 Practice for Handling of Ultra-Pure Water Samples
Test Method B: 16–22
Fluoride 0–14 0.7
3. Terminology
Acetate 0–414 6.8
Formate 0–346 5.6
3.1 Definitions:
3.1.1 For definitions of terms used in these test methods
1.2 It is the user’s responsibility to ensure the validity of
refer to Terminology D 1129.
these test methods for waters of untested matrices.
3.2 Definitions of Terms Specific to This Standard:
1.3 The common practical range of Test Method A is as
3.2.1 analytical columns—a combination of one or more
follows: chloride, 1 to 100 μg/L, phosphate, 3 to 100 μg/L, and
guard columns followed by one or more separator columns
sulfate, 2 to 100 μg/L.
used to separate the ions of interest. It should be remembered
1.4 The common practical range of Test Method B is as
that all of the columns in series contribute to the overall
follows: fluoride, 1 to 100 μg/L, acetate, 10 to 200 μg/L, and
capacity of the analytical column set.
formate, 5 to 200 μg/L.
3.2.2 breakthrough volume—the maximum sample volume
1.5 The values stated in SI units are to be regarded as the
that can be passed through a concentrator column before the
standard.
least tightly bound ion of interest is eluted.
1.6 This standard does not purport to address all of the
3.2.3 concentrator column—an ion exchange column used
safety concerns, if any, associated with its use. It is the
to concentrate the ions of interest and thereby increase method
responsibility of the user of this standard to establish appro-
sensitivity.
3.2.4 eluant—the ionic mobile phase used to transport the
These test methods are under the jurisdiction of ASTM Committee D19 on
sample through the exchange column.
Water and are the direct responsibility of Subcommittee D19.03 on Sampling of
3.2.5 guard column—a column used before the separator
Water and Water-Formed Deposits, Surveillance of Water, and Flow Measurement
column to protect it from contaminants, such as particulate
of Water.
matter or irreversibly retained materials.
Current edition approved April 15, 1994. Published September 1994.
Limit of detection is lowest measurable concentration not reportable as zero at
99 % level of confidence as per EPRI study as cited in Sections 15 and 22.
3 4
Insufficient data to calculate limit of detection. Annual Book of ASTM Standards, Vol 11.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D 5542 – 94 (1999)
3.2.6 ion chromatography—a form of liquid chromatogra- 5.2 Purity of Water— Unless otherwise indicated, refer-
phy in which ionic constituents are separated by ion exchange ences to water shall be understood to mean reagent water
followed by a suitable detection means. conforming to Specification D 1193, Type I. Column life may
3.2.7 resolution—the ability of an analytical column to be extended by passing Type I water through a 0.22 μm filter
separate constituents under specific test conditions. prior to use. Freshly prepared water should be used for making
3.2.8 separator column—the ion exchange column used to the low level standards intended for calibration. The detection
separate the ions of interest according to their retention limits of this method will be limited by the purity of the water
characteristics prior to their detection. and reagents used to make the standards. The purity of the
3.2.9 suppressor device—a device that is placed between water may be checked by use of this method. Anion concen-
the analytical columns and the detector. Its purpose is to inhibit trations of less than 0.2 ppb each, is typical of Type I water.
detector response to the ionic constituents in the eluant, so as
6. Sampling
to lower the detector background and at the same time enhance
detector response to the ions of interest. 6.1 Collect samples in accordance with Practice D 1066,
Specification D 1192, Practice D 3370, and Practice D 4453, as
4. Significance and Use
applicable.
4.1 The anions fluoride, chloride, and sulfate have been 6.2 Collect samples in polystyrene bottles that should be
identified as important contributors to corrosion of high pres- filled to overflow and capped, so as to exclude air. Glass
sure boilers, electric power turbines and their associated heat sample bottles should not be used, as they can contribute ionic
exchangers. Many electric power utilities attempt to reduce contamination.
these contaminants in their boiler feed water to less than 1 6.3 Samples should be analyzed within 48 h of sampling.
μg/L. When acetate, formate or phosphate data are required, refrig-
4.2 In the semiconductor manufacturing process these ions, erate at 4° Celsius upon sampling.
among others, have been identified as a cause of low product 6.4 To prevent added ionic contamination, no preservation
yield and, thus, must be monitored and controlled to levels
or filtration of the sample shall be done.
similar to those required by the electric power industry.
TEST METHOD A—CHLORIDE, PHOSPHATE, AND
4.3 Low molecular weight organic acids, such as acetate and
SULFATE
formate, have been found in many steam generator feed waters
and condensates. They are believed to come from the high
7. Scope
temperature breakdown of organic matter found in boiler make
7.1 This test method is optimized for the quantitative
up water. It is felt that these organic acids promote corrosion by
determination of trace levels of chloride, phosphate, and
lowering the pH of boiler waters and may even be corrosive
sulfate. Anions such as fluoride, acetate, and formate can be
themselves.
detected by this method, but are not reliably resolved from
4.4 Such low molecular weight organics may also be
each other. See Fig. 1 for a typical chromatogram.
produced when ultraviolet light is used to produce bacteria-free
7.2 Using a concentrated sample volume of 20 mL, the test
water for semiconductor processing. Such polar organic con-
method is applicable in the range outlined in Section 1. The
taminants are suspected of causing reduced semiconductor
range of this test method may be extended by concentrating a
yields.
smaller or a larger sample volume. Be sure not to exceed
4.5 Phosphates are commonly added to drum boilers in the
concentrator column breakthrough volume (see annex).
low mg/L level to precipitate calcium and magnesium and
thereby prevent scale formation. Ion chromatography can be
8. Summary of Test Method
used to monitor the concentration of such chemicals in boiler
8.1 A flow diagram of an ion chromatograph is shown in
water, as well as detect unwanted carry-over into the steam.
Fig. 2. With the sampling valve in the load position, the
5. Reagents
desired volume of sample (for example, 20 mL) is pumped
through a concentrator column where the anions of interest are
5.1 Purity of Reagents—Reagent grade chemicals shall be
trapped. The sampling valve is then switched to the inject
used in all tests. Unless otherwise indicated, it is intended that
position and the pumped eluant, containing sodium carbonate
all reagents shall conform to the specifications of the Commit-
and bicarbonate, sweeps these anions through the analytical
tee on Analytical Reagents of the American Chemical Society,
columns where they are separated according to their retention
where such specifications are available.
characteristics relative to the anions in the eluant. The eluant
5.1.1 Other grades may be used, provided it is first ascer-
stream next passes through a suppressor where all cations are
tained that the reagent is of sufficiently high purity to permit its
exchanged for hydrogen ions. This converts the carbonate and
use without lessening the accuracy of the determination.
bicarbonate in the eluant to the poorly ionized carbonic acid,
thus reducing the background conductivity.
8.1.1 This also converts the anions to their acid form, thus
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
enhancing their conductivity. The eluant stream then passes
listed by the American Chemical Society, see Analar Standards for Laboratory
through an electrical conductivity detector, where the separated
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
anions are detected. A strip chart recorder and/or a chromato-
and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
MD. graphic integrator is used for data presentation.
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D 5542 – 94 (1999)
FIG. 2 Schematic of an Ion Chromatograph
9.4 Samples containing high (mg/L) concentrations of am-
monia, morpholine, or other additives which raise the hydrox-
ide concentration (pH) of the sample may cause low break-
through volumes. This problem may be avoided by taking such
samples after the cation resin of a cation conductivity detector.
10. Apparatus
10.1 Ion Chromatograph—The ion chromatograph should
have the following components assembled, as shown in Fig. 2.
10.1.1 Eluant and Regenerant Containers.
10.1.2 Eluant Pump, capable of delivering 2 to 5 mL/min of
FIG. 1 Anions by Test Method A
eluant at a pressure of up to 2000 psig. Wetted parts of the
pump should be nonmetallic, so as not to contaminate the
8.2 The anions are identified based on their retention times,
concentrator or analytical columns with metals, or both.
when compared to known standards. Quantitation is accom-
10.1.3 Sample Pump, capable of delivering up to 5 mL/min
plished by measuring the peak height or area and comparing it
of sample at a pressure of at least 200 psig. Wetted parts of the
to a calibration curve generated from known standards.
pump should be nonmetallic, so as not to contaminate the
9. Interferences
concentrator and/or analytical columns with metals.
9.1 When working at microgram per litre concentrations 10.1.4 Concentrator Column—Anion exchange column
and lower, contamination can be a very serious problem. with sufficient capacity to concentrate at least 20 mL of sample
Extreme care must be exercised in all phases of the test method before reaching chloride breakthrough.
10.1.5 Guard Column— Anion exchange column, typically
(sample collection, storage, and analysis) to eliminate contami-
nation. of the same anion exchange material used in the separator
9.2 As with other types of chromatography, if one of the column. The purpose of this column is to protect the separator
sample components is present at very high concentration column from particulate matter and irreversibly retained ma-
levels, it may interfere by causing a very large peak on the terials.
chromatogram that could mask other peaks present. This type 10.1.6 Separator Column— Anion exchange column ca-
of interference may normally be minimized by dilution of the pable of separating chloride from the injection void volume, as
sample, depending on the concentration of other anions. well as resolving the anions chloride, phosphate, and sulfate.
9.3 When loading concentrator columns, high concentra- 10.1.7 Suppressor Column—A membrane based cation ex-
tions of certain anions may cause low breakthrough volumes of changer which is continuously regenerated by a flow of dilute
other anions. These certain anions may act as eluants and sulfuric acid.
displace other anions from the concentrator column. See annex 10.1.8 Detector—A low-volume, flow-through,
to determine breakthrough volume. Do not attempt to concen- temperature-compensated electrical conductivity cell equipped
trate a volume of sample greater than 80 % of the breakthrough with a meter capable of reading from 0 to 1000 uS/cm on a
volume. linear scale.
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D 5542 – 94 (1999)
10.1.9 Recorder, compatible with the detector output with a levels expected in the samples. If desired, a standard may be
full-scale response time of2sor less. prepared that contains all six anions. A typical range would be
10.1.10 Integrator—An electronic integrator, such as is 5, 10, and 25 μg/L of each anion per standard. This would be
used with gas and liquid chromatographs, may be used to prepared by taking 5, 10, and 25 mL of the standard stock
quantitate peak area, as well as peak height. The peak area data solution and diluting to 1 L with water for each standard. The
can be used in the same way peak height is used to quantitate blank standard is a portion of the same water used to prepare
results. the working standard solutions.
10.1.11 Sample Bottles— Polystyrene culture bottles with a
11.6 Some investigators prefer to work with standard solu-
total capacity of approximately 270 mL have been found
tions that are prepared by diluting microlitre qualities of stock
satisfactory.
standards (or low level standards) using push-button microlitre
10.1.12 The following is a summary of the columns and
pipet
...
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