ASTM D6581-00
(Test Method)Standard Test Method for Bromate, Bromide, Chlorate, and Chlorite in Drinking Water by Chemically Suppressed Ion Chromatography
Standard Test Method for Bromate, Bromide, Chlorate, and Chlorite in Drinking Water by Chemically Suppressed Ion Chromatography
SCOPE
1.1 This test method covers the determination of the oxyhalides - chlorite, bromate, and chlorate, and bromide, in raw water, finished drinking water and bottled (non-carbonated) water by chemically suppressed ion chromatography. The ranges tested using this method for each analyte were as follows:Chlorite20 to 500 g/LBromate5 to 30 g/LBromide20 to 200 g/LChlorate20 to 500 g/L
The upper limits may be extended by appropriate sample dilution or by the use of a smaller injection volume. Other ions of interest, such as fluoride, chloride, nitrite, nitrate, phosphate, and sulfate may also be determined using this method. However, analysis of these ions is not the object of this test method.
1.2 It is the user's responsibility to ensure the validity of these test methods for waters of untested matrices.
1.3 This test method is technically equivalent with Part B of U.S. EPA Method 300.1, titled "The Determination of Inorganic Anions in Drinking Water by Ion Chromatography".
1.4 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 6581–00
Standard Test Method for
Bromate, Bromide, Chlorate, and Chlorite in Drinking Water
by Chemically Suppressed Ion Chromatography
This standard is issued under the fixed designation D 6581; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope D 3856 Guide for Good Laboratory Practices
D 5810 Standard Guide for Spiking intoAqueous Samples
1.1 This test method covers the determination of the oxy-
D 5847 Standard Practice for the Writing Quality Control
halides - chlorite, bromate, and chlorate, and bromide, in raw
Specifications for StandardTest Methods forWaterAnaly-
water, finished drinking water and bottled (non-carbonated)
sis
water by chemically suppressed ion chromatography. The
ranges tested using this method for each analyte were as
3. Terminology
follows:
3.1 Definitions—For definition of terms used in the test
Chlorite 20 to 500 µg/L
methods, refer to Terminology D 1129.
Bromate 5 to 30 µg/L
Bromide 20 to 200 µg/L
3.2 Definitions of Terms Specific to This Standard:
Chlorate 20 to 500 µg/L
3.2.1 ion chromatography—a form of liquid chromatogra-
The upper limits may be extended by appropriate sample phy in which ionic constituents are separated by ion exchange
dilution or by the use of a smaller injection volume. Other ions then detected by an appropriate detection means, typically
ofinterest,suchasfluoride,chloride,nitrite,nitrate,phosphate, conductance.
and sulfate may also be determined using this method. How- 3.2.2 eluent—the ionic mobile phase used to transport the
ever, analysis of these ions is not the object of this test method. sample through the chromatographic system.
1.2 It is the user’s responsibility to ensure the validity of 3.2.3 analytical column—the ion exchange column used to
these test methods for waters of untested matrices. separate the ions of interest according to their retention
1.3 This test method is technically equivalent with Part B of characteristics prior to detection.
U.S. EPA Method 300.1 , titled “The Determination of Inor- 3.2.4 guard column—a column used before the analytical
ganic Anions in Drinking Water by Ion Chromatography”. column to protect it from contaminants, such as particulates or
1.4 This standard does not purport to address all of the irreversibly retained material.
safety concerns, if any, associated with its use. It is the 3.2.5 analytical column set—a combination of one or more
responsibility of the user of this standard to establish appro- guard columns, followed by one or more analytical columns
priate safety and health practices and determine the applica- usedtoseparatetheionsofinterest.Allofthecolumnsinseries
bility of regulatory limitations prior to use. then contribute to the overall capacity and resolution of the
analytical column set.
2. Referenced Documents
3.2.6 suppressor device—an ion exchange based device that
2.1 ASTM Standards:
is placed between the analytical column set and the conduc-
D 1129 Terminology Relating to Water tivity detector. Its purpose is to minimize detector response to
D 1193 Specification for Reagent Water
the ionic constituents in the eluent, in order to lower back-
D 2777 Standard Practice for Determination of Precision ground conductance; and at the same time enhance the con-
and Bias of Applicable Methods of Committee D-19 on
ductivity detector response of the ions of interest.
Water 3.2.7 resolution—the ability of an analytical column to
D 3370 Practices for Sampling Water
separate the method analytes under specific test conditions.
4. Summary of Test Method
These test methods are under the jurisdiction of ASTM Committee D19 on
4.1 Oxyhalides (chlorite, bromate, and chlorate) and bro-
Water and are the direct responsibility of Subcommittee D19.05 on Inorganic
mide in raw water, finished drinking water and bottled water
Constituents in Water.
are determined by ion chromatography. A sample (200 µL) is
Current edition approved July 10, 2000. Published October 2000.
U.S. EPA Method 300.1, Cincinnati, OH, 1997.
injected into an ion chromatograph and the pumped eluent
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.
D 6581–00
(sodium carbonate) sweeps the sample through the analytical e.g., Dionex IonPac AG9-HC, or equivalent. The purpose of
column set. Here, anions are separated from the sample matrix this column is to protect the analytical column from particulate
according to their retention characteristics, relative to the matter and irreversibly retained material.
anions in the eluent. 7.1.4 Analytical Column—Anion exchange column capable
The separated anions in the eluent stream then pass through of separating the ions of interest from each other, as well as
a suppressor device, where all cations are exchanged for from other ions which commonly occur in the sample matrix,
hydronium ions.This converts the eluent to carbonic acid, thus e.g., Dionex IonPac AS9-HC (4 mm ID), or equivalent. The
reducing the background conductivity. This process also con- separation shall be at least as good as that shown in Fig. 2.The
verts the sample anions to their acid form, thus enhancing their use of 2 mm IDAS9-HC column, in conjunction with a 50 µL
conductivity. The eluent stream then passes through a conduc- sample loop, may improve the peak shape for early eluting
tivity cell, where they are detected. A chromatographic inte- anions, such as chlorite and bromate.
grator or appropriate computer-based data system is typically
NOTE 1—TheAnalytical Column Set (see 3.2.3) should be able to give
used for data presentation.
baseline resolution of all anions, even for a 200 µLinjection containing up
4.2 The anions are identified based on their retention times
to 200 mg/L, each, of common anions, such as chloride, bicarbonate, and
compared to known standards. Quantification is accomplished sulfate.
by measuring anion peak areas and comparing them to the
7.1.5 Suppressor Device—A suppressor device based upon
areas generated from known standards.
cation exchange principles. In this method, a membrane-based
self regenerating suppressor device, Dionex ASRS-ULTRA,
5. Significance and Use
was used. An equivalent suppressor device may be used
5.1 The oxyhalides chlorite, chlorate, and bromate are provided that comparable method detection limits are achieved
inorganic disinfection by-products (DBPs) of considerable
and that adequate baseline stability is attained.
health risk concern worldwide. The occurrence of chlorite and
7.1.6 Conductivity Detector—A low-volume, flow through,
chlorate is associated with the use of chlorine dioxide, as well
temperaturestabilized conductivity cell equipped with a meter
as hypochlorite solutions used for drinking water disinfection.
capable of reading from 0 to 1000 µS/cm on a linear scale.
The occurrence of bromate is associated with the use of ozone
7.1.7 Data System—A chromatographic integrator or
for disinfection, wherein naturally occurring bromide is oxi-
computer-based data system capable of graphically presenting
dized to bromate. Bromide is a naturally occurring precursor to
the detector output signal versus time, as well as presenting the
the formation of bromate.
integrated peak areas.
8. Reagents and Materials
6. Interferences
8.1 Purity of Reagents—Reagent grade chemicals shall be
6.1 Positive errors can be caused by progressive oxidation
used in all tests. Unless otherwise indicated, it is intended that
of residual hypochlorite and/or hypobromite in the sample to
all reagents shall conform to the specifications of the Commit-
the corresponding chlorate and bromate. Furthermore, chlorite
tee onAnalytical Reagents of theAmerican Chemical Society,
can also be oxidized to chlorate, causing negative errors for
where such specifications are available. Other grades may be
chloriteandpositiveerrorsforchlorate.Theseinterferencesare
used, provided it is first ascertained that the reagent is of
eliminated by the sample preservation steps outlined in 8.5.
sufficiently high purity to permit its use without reducing the
Chloride present at > 200 mg/Land carbonate present at > 300
accuracy of the determination.
mg/Lcan interfere with bromate determination. These interfer-
8.2 Purity of Water—Unless otherwise indicated, references
ences can be minimized, or eliminated, by the sample pretreat-
to water shall be understood to mean reagent water conforming
ment steps outlined in 8.6. Fluoride and low molecular weight
to Specification D 1193,Type I. Other reagent water types may
monocarboxylic acids, present at mg/L concentrations, may
be used, provided it is first ascertained that the water is of
interfere with the quantitation of chlorite and bromate.
sufficiently high purity to permit its use without adversely
affecting the bias and precision of the determination.
7. Apparatus
8.3 Eluent, Concentrate (90.0 mM Sodium Carbonate)—
7.1 Ion Chromatography Apparatus—Analytical system
Dissolve 9.540 g of sodium carbonate in 1000 mL of water.
complete with all required accessories, including eluent pump,
8.4 Eluent, Analysis (9.0 mM Sodium Carbonate)—Dilute
injector, syringes, columns, suppressor, conductivity detector,
100.0 mL of Eluent Concentrate (8.3) to 1.000 L with water.
data system and compressed gasses.
8.4.1 The Eluent Analysis solution (9.0 mM Sodium Car-
7.1.1 Eluent Pump—capableofdelivering0.25to5mL/min
bonate)mustbepurgedfor10minuteswithheliumpriortouse
of eluent at a pressure of up to 4000 psi.
to remove dissolved gasses in order to ensure optimal system
7.1.2 Injection Valve—A low dead-volume switching valve
performance.
that will allow the loading of a sample into a sample loop and
8.5 Ethylenediamine (EDA) Preservation Solution (50.0
subsequent injection of the loop contents into the eluent
g/L)—Dilute 11.2 mL of ethylenediamine (99%) to 200 mL
stream. A loop size of up to 200 µL may be used without
compromising the resolution of early eluting peaks, such as
“Reagent Chemicals,American Chemical Society Specifications,”Am. Chemi-
chlorite and bromate.
cal Soc., Washington, DC. For suggestions on the testing of reagents not listed by
7.1.3 Guard Column—Anion exchange column typically
theAmerican Chemical Society, see “Analar Standards for Laboratory Chemicals,”
packed with the same material used in the analytical column, by BDH Ltd., Poole, Dorset, U.K., and the “United States Pharmacopoeia.”
D 6581–00
FIG. 1 Chromatogram of a Standard Containing Low µg/L Oxyhalides, and Bromide, in the Presence of Common Inorganic Anions. See
Table 1 for Analysis Conditions.
FIG. 2 Chromatogram of Low µg/L Oxyhalides, and Bromide, in Simulated Drinking Water. See Table 1 for Analysis Conditions.
with reagent water. Prepare this solution fresh monthly. Add cation exchange SPE cartridges can be used to minimize the
1.00 mL of this solution per 1.000 L of blank, standard or carbonate and chloride interferences, respectively, if required.
sample to produce a final EDA concentration of 50 mg/L.
Dionex OnGuard-H and OnGuard-Ag cartridges have been
8.6 SPE Sample Preatment Cartridges— Chloride present
at > 200 mg/L and carbonate present at > 300 mg/L can
+ +
interfere with bromate determination. H form and Ag form
D 6581–00
shown to be suitable for this application. The use of these 11. Quality Control
pretreatment cartridges will effect recoveries for bromide,
11.1 Before this test is applied to analyzing unknown
requiring that it be analyzed in a separate run.
samples, the analyst should establish quality control proce-
8.7 Suppressor Regenerant Solution— If a suppressor re-
dures as recommended in Guide D 3856.
quiring chemical regeneration is used, the regenerant solution
11.2 The laboratory using this test should perform an initial
is prepared by cautiously adding 3.00 mL of concentrated
demonstration of laboratory capability. Analyze seven repli-
sulfuric acid (sp. gr. 1.84) to 4.000 Lof water. If anAnion Self
cates of an Initial Demonstration of Performance (IDP) solu-
Regenerating Suppressor is used, it should be operated in the
tion. The IDP solution contains method analytes of known
external water mode.
concentration, prepared from a different source to the calibra-
8.8 Standard Solutions, Stock (1.00 mL = 1.00 mg)—
tion standards, used to fortify reagent water, which also
Purchase certified solutions or prepare stock standard solutions
contains a final EDA concentration of 50 mg/L (8.5). Ideally,
from the following salts, as described below:
the IPD solution should be prepared by an independent source
—
8.8.1 Bromate (BrO ) Solution, Stock (1.00 mL = 1.00 mg
from reference materials. The level 3 standard used for the
—
BrO )—Dissolve 1.180 g of sodium bromate (NaBrO)in
3 3
method precision and bias study is recommended as an IDP
water and dilute to 1.000 L.
solution.
—
8.8.2 Bromide (Br ) Solution, Stock (1.00 mL = 1.00 mg
The mean and standard deviation of the seven values should
—
Br )—Dissolve 1.288 g of sodium bromide (NaBr) in water
then be calculated and compared, according to Standard
and dilute to 1.000 L.
D 5847, to the single operator precision and recovery estab-
—
8.8.3 Chlorate (ClO ) Solution, Stock (1.00 mL = 1.00 mg
lished for this Test Method. The upper limit for acceptable
—
C1O )—Dissolve 1.275 g of sodium chlorate (NaClO)in
3 3 precision and the range of acceptable recoveries are detailed
water and dilute to 1.000 L.
below:
—
8.8.4 Chlorite (ClO ) Solution, Stock (1.00 mL = 1.00 mg
IDP Solution Acceptable IDP
—
ClO )—Dissolve 1.680 g of sodium chlorite (NaClO)in
Analyte Amount Method S Precision, n = 7
2 2 0
water and dilute to 1.000 L. Note that as sodium chlorite is
Chlorite 180 µg/L 4.4 µg/L # 11.8 µg/L
usually available only as an 80% technical grade salt, the 80%
Bromate 10 µg/L 0.66 µg/L # 1.67 µg/L
purity is accounted for in the 1.680 g weight cited above. If an
Bromide 75 µg/L 3.8 µg/L # 9.6 µg/L
Chlorate 180 µg/L 12.0 µg/L # 32.1 µg/L
alternate purity is used, make an appropriate adjustment in the
weight of salt used after determining the exact percentage of
NaClO , which can be done using an iodometric titration
Method Mean Lower Acceptable Upper Acceptable
,
2 6
Analyte Recovery IDP Recovery IDP Recovery
procedure.
8.9 Reagent Blank—Add 1.00 mL of
...
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