ASTM D5996-96(2000)
(Test Method)Standard Test Method for Measuring Anionic Contaminants in High-Purity Water by On-Line Ion Chromatography
Standard Test Method for Measuring Anionic Contaminants in High-Purity Water by On-Line Ion Chromatography
SCOPE
1.1 This test method covers on-line analysis of high-purity water by the ion chromatography technique. This test method is applicable for measuring various anionic contaminants in high-purity water, typically in the range of 0.02 to 100 µg/L. This test method is used to determine the concentration of acetate, formate, chloride, fluoride, phosphate, nitrate, and sulfate in a continuously flowing sample. The range of the test method is only as good as the reagent water available for preparing standards. At extremely low concentrations,
1.2 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
Designation: D 5996 – 96 (Reapproved 2000)
Standard Test Method for
Measuring Anionic Contaminants in High-Purity Water by
On-Line Ion Chromatography
This standard is issued under the fixed designation D 5996; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope D5542 TestMethodsforTraceAnionsinHighPurityWater
by Ion Chromatography
1.1 This test method covers on-line analysis of high-purity
water by the ion chromatography technique. This test method
3. Terminology
is applicable for measuring various anionic contaminants in
3.1 Fordefinitionsoftermsusedinthistestmethod,referto
high-purity water, typically in the range of 0.02 to 100 µg/L.
Terminology D1129.
This test method is used to determine the concentration of
3.2 Definitions of Terms Specific to This Standard:
acetate, formate, chloride, fluoride, phosphate, nitrate, and
3.2.1 analytical column,, n—a column used to separate the
sulfate in a continuously flowing sample. The range of the test
anions of interest.
method is only as good as the reagent water available for
3.2.2 analytical column set,, n—a combination of one or
preparing standards. At extremely low concentrations, <1.0
more guard columns followed by one or more analytical
µg/L, preparing standards is difficult, and extra care must be
columns.
taken in their preparation. The sample may have to be
3.2.3 anion suppressor device,, n—a device that is placed
conditioned from higher pressures and temperatures to condi-
between the analytical columns and the detector. Its purpose is
tionsthataresuitableforusebyon-lineinstruments.Therange
to inhibit detector response to the ionic constituents in the
ofthetestmethodisonlyasgoodasthereagentwateravailable
eluant, so as to lower the detector background and at the same
for standard preparation.
time enhance detector response to the ions of interest.
1.2 This standard does not purport to address all of the
3.2.4 breakthrough volume,, n— the maximum sample vol-
safety concerns, if any, associated with its use. It is the
ume that can be passed through a concentrator column before
responsibility of the user of this standard to establish appro-
the least tightly bound ion of interest is eluted. All of the
priate safety and health practices and determine the applica-
columns in series contribute to the overall capacity of the
bility of regulatory limitations prior to use.
analytical column set.
2. Referenced Documents 3.2.5 concentrator column,, n—an ion exchange column
used to concentrate the ions of interest and thereby increase
2.1 ASTM Standards:
method sensitivity.
D 1066 Practice for Sampling Steam
2 3.2.6 eluant,, n—the ionic mobile phase used to transport
D 1129 Terminology Relating to Water
the sample through the analytical column.
D 1192 Specification for Equipment for Sampling Water
2 3.2.7 guard column,, n—a column used before the analyti-
and Steam in Closed Conduits
cal column to protect it from contaminants, such as particulate
D 1193 Specification for Reagent Water
matter or ionic species that may chemically foul the resins and
D2777 PracticefortheDeterminationofPrecisionandBias
degrade their performance.
ofApplicableTest Methods of Committee D-19 onWater
3.2.8 ion chromatography,, n—a form of liquid chromatog-
D 3370 Practices for Sampling Water from Closed Con-
raphy in which ionic constituents are separated by ion ex-
duits
change followed by a suitable detection means.
D 3864 Guide for Continual On-Line Monitoring Systems
3.2.9 resolution,, n—the ability of an analytical column to
for Water Analysis
separate constituents under specific test conditions.
D4453 PracticeforHandlingofUltra-PureWaterSamples
4. Summary of Test Method
4.1 A continuously flowing sample is injected into the
This test method is under the jurisdiction ofASTM Committee D19 on Water
instrument through a sample injection valve. The sample is
and is the direct responsibility of Subcommittee D19.03 on Sampling of Water and
pumped through a concentrator column where the anions of
Water-Formed Deposits, Surveillance of Water, and Flow Measurement of Water.
interest are collected on ion-exchange resin. After a suitable
Current edition approved July 10, 1996. Published October 1996.
Annual Book of ASTM Standards, Vol 11.01. volume of sample has been passed through the concentrator
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 5996 – 96 (2000)
column, sample flow is diverted and an eluant is pumped 5.7 Additionally, on-line monitoring significantly reduces
throughtheconcentratorcolumntoremovethetrappedanions. the potential for contamination of high-purity water samples, a
This eluant then flows through an analytical column set where significant problem when sampling and testing high-purity
theanionsareseparatedbasedontheretentioncharacteristicof water.
each anion relative to the eluant used. The eluant stream
containing the anions of interest passes through a suppressor 6. Interferences
device where the cations from the eluant are exchanged for
6.1 When working with low concentration samples, blanks,
hydrogen ions, converting the anions to their acid form. After
and standards, contamination can be a serious problem. Ex-
the suppressor device, the eluant solution passes through a
treme care must be exercised in all phases of this test method.
conductivity detector where the separated anions are detected.
6.2 Improper sample line material or sample lines that have
Detectionlimitsfortheanionsareenhancedbecausetheanions
not been properly conditioned can give results that may not be
are in the acid form rather than the salt.
truly representative of the process stream. Absorption/
4.2 The anions are identified based on the retention time as
desorption of anions on sample line wall deposits can change
compared to known standards. By measuring peak height or
analytical results. Maintaining a minimum sample flow of 1.8
area and comparing the detector response to known standards,
m/s(6ft/s)willminimizedepositbuilduponsamplelinewalls,
the anions can be quantified.
reducing the potential for absorption/desorption of anions.
6.3 A single anion present at a concentration significantly
5. Significance and Use
higher than other anions could mask closely adjacent peaks on
5.1 In the power-generation industry, high-purity water is
the chromatogram.
usedtoreducecorrosionfromanions,suchassulfate,chloride,
6.4 Low breakthrough volumes may be experienced when
and fluoride. These anions are known to be detrimental to
continuouslymonitoringforanionsinwaterthathashaditspH
materials of construction used in steam generators, reactor
raised by ammonia, morpholine, or other additives. This
vessel internals and recirculation piping, heat exchangers,
interference can be eliminated by taking the sample from the
connectivepiping,andturbines.Mostelectricgeneratingplants
effluent of a cation resin column.
try to control these anions to <1.0 µg/L in the steam generator
6.5 Identification of the anion is based on retention time of
feed water. Some nuclear power plants have been able to
the anion of interest. An interfering anion having the same
control anion contaminants at less than 0.02 µg/L.
retention time as one of the anions of interest will result in
5.2 These anions and others cause low product yields in
erroneously high values for that anion.
semiconductor manufacturing. They are also monitored and
6.6 When loading a concentrator column, high concentra-
controlled at similarly low levels as in the electric power
tions of interfering anions may cause low breakthrough vol-
industry.
umes of other anions. These interfering anions may act as an
5.3 Low molecular weight organic acids (acetate, formate,
eluantanddisplaceotheranionsfromtheconcentratorcolumn.
propionate) have been detected in steam generator feed water.
SeeAnnexA1 to determine breakthrough volume. Do not load
These low molecular weight organic materials are believed to
a sample volume greater than 80% of the breakthrough
behigh-temperaturedegradationproductsofchemicalsusedto
volume.
control cycle water pH and organic contaminants in cycle
makeup water.
7. Apparatus
5.4 In the semiconductor industry, anion contaminants may
7.1 Ion chromatograph with the following components:
come from the breakdown of low molecular weight organic
7.1.1 Eluant Introduction System—The wetted portion of
materials by ultraviolet light radiation, which is frequently
the eluant pump should be nonmetallic or of a corrosion-
used to produce bacteria-free water. These organic compounds
resistantmetaltopreventcontaminationofthechromatography
may also contribute to low product yield.
columns.
5.5 Theproductionofhigh-puritywaterforprocessmakeup
7.1.2 Sample Injection System—The wetted portion of the
and use frequently employs the use of demineralizers to
sample pump should be nonmetallic or of a corrosion-resistant
remove unwanted anion contaminants. Also in the electric
metal to prevent metal contamination of the chromatography
power industry, demineralizers are used in the process stream
columns.
to maintain low levels of these contaminants. As such, it is
7.1.3 Anion Suppressor Device.
important to monitor this process to ensure that water quality
standards are being met.These processes can be monitored for 7.1.4 Conductivity Cell, low dead volume (1 µL). Tempera-
the above mentioned anions. ture compensated or corrected flow through conductivity
detectorshouldbecapableofmeasuringconductivityfrom0to
5.6 On-line measurements of these contaminants provide a
1000 µS/cm. If temperature controlled conductivity detector is
greater degree of protection of the processes by allowing for
used, temperature control should be at 60.5°C or better.
frequent on-line measurement of these species. Early detection
of contaminant ingress allows for quicker corrective action to 7.1.5 Suppressor Device Regenerant System—Some manu-
locate,reduce,oreliminate,orcombinationthereof,thesource. facturers provide integrated regenerant systems that reduce the
Grab samples will not provide the same level of protection consumption of eluant. Electrochemical suppressor regenerant
because of their intermittent nature and the longer time systems can be used, eliminating the need to prepare regener-
required to obtain and then analyze the sample. ant solutions.
D 5996 – 96 (2000)
8. Reagents 8.12 Anion Intermediate Solutions—Prepare a 1000 µg/L
standard of each anion by diluting 1.00 mL of each stock
...
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