ASTM D6581-00(2005)
(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
SIGNIFICANCE AND USE
The oxyhalides chlorite, chlorate, and bromate are inorganic disinfection by-products (DBPs) of considerable health risk concern worldwide. The occurrence of chlorite and chlorate is associated with the use of chlorine dioxide, as well as hypochlorite solutions used for drinking water disinfection. The occurrence of bromate is associated with the use of ozone for disinfection, wherein naturally occurring bromide is oxidized to bromate. Bromide is a naturally occurring precursor to the formation of bromate.
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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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D 6581–00 (Reapproved 2005)
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 1193 Specification for Reagent Water
D 2777 Standard Practice for Determination of Precision
1.1 This test method covers the determination of the oxy-
and Bias of Applicable Methods of Committee D19 on
halides - chlorite, bromate, and chlorate, and bromide, in raw
Water
water, finished drinking water and bottled (non-carbonated)
D 3370 PracticesforSamplingWaterfromClosedConduits
water by chemically suppressed ion chromatography. The
D 3856 Guide for Good Laboratory Practices in Laborato-
ranges tested using this method for each analyte were as
ries Engaged in Sampling and Analysis of Water
follows:
D 5810 Standard Guide for Spiking into Aqueous Samples
Chlorite 20 to 500 µg/L
D 5847 Standard Practice for the Writing Quality Control
Bromate 5 to 30 µg/L
Bromide 20 to 200 µg/L
Specifications for StandardTest Methods forWaterAnaly-
Chlorate 20 to 500 µg/L
sis
The upper limits may be extended by appropriate sample
3. Terminology
dilution or by the use of a smaller injection volume. Other ions
ofinterest,suchasfluoride,chloride,nitrite,nitrate,phosphate, 3.1 Definitions—For definition of terms used in the test
and sulfate may also be determined using this method. How- methods, refer to Terminology D 1129.
ever, analysis of these ions is not the object of this test method. 3.2 Definitions of Terms Specific to This Standard:
1.2 It is the user’s responsibility to ensure the validity of 3.2.1 ion chromatography—a form of liquid chromatogra-
these test methods for waters of untested matrices. phy in which ionic constituents are separated by ion exchange
1.3 This test method is technically equivalent with Part B of then detected by an appropriate detection means, typically
U.S. EPA Method 300.1 , titled “The Determination of Inor- conductance.
ganic Anions in Drinking Water by Ion Chromatography”. 3.2.2 eluent—the ionic mobile phase used to transport the
1.4 This standard does not purport to address all of the sample through the chromatographic system.
safety concerns, if any, associated with its use. It is the 3.2.3 analytical column—the ion exchange column used to
responsibility of the user of this standard to establish appro- separate the ions of interest according to their retention
priate safety and health practices and determine the applica- characteristics prior to detection.
bility of regulatory limitations prior to use. 3.2.4 guard column—a column used before the analytical
column to protect it from contaminants, such as particulates or
2. Referenced Documents
irreversibly retained material.
2.1 ASTM Standards:
3.2.5 analytical column set—a combination of one or more
D 1129 Terminology Relating to Water guard columns, followed by one or more analytical columns
usedtoseparatetheionsofinterest.Allofthecolumnsinseries
then contribute to the overall capacity and resolution of the
These test methods are under the jurisdiction of ASTM Committee D19 on
analytical column set.
Water and are the direct responsibility of Subcommittee D19.05 on Inorganic
3.2.6 suppressor device—an ion exchange based device that
Constituents in Water.
Current edition approved Jan. 1, 2005. Published January 2005.
is placed between the analytical column set and the conduc-
Originally approved in 2000. Last previous edition approved in 2000 as
tivity detector. Its purpose is to minimize detector response to
D 6581 – 00.
the ionic constituents in the eluent, in order to lower back-
U.S. EPA Method 300.1, Cincinnati, OH, 1997.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or ground conductance; and at the same time enhance the con-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
ductivity detector response of the ions of interest.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 6581–00 (2005)
3.2.7 resolution—the ability of an analytical column to 7.1.2 Injection Valve—A low dead-volume switching valve
separate the method analytes under specific test conditions. that will allow the loading of a sample into a sample loop and
subsequent injection of the loop contents into the eluent
4. Summary of Test Method
stream. A loop size of up to 200 µL may be used without
compromising the resolution of early eluting peaks, such as
4.1 Oxyhalides (chlorite, bromate, and chlorate) and bro-
chlorite and bromate.
mide in raw water, finished drinking water and bottled water
7.1.3 Guard Column—Anion exchange column typically
are determined by ion chromatography. A sample (200 µL) is
packed with the same material used in the analytical column,
injected into an ion chromatograph and the pumped eluent
e.g., Dionex IonPac AG9-HC, or equivalent. The purpose of
(sodium carbonate) sweeps the sample through the analytical
this column is to protect the analytical column from particulate
column set. Here, anions are separated from the sample matrix
matter and irreversibly retained material.
according to their retention characteristics, relative to the
7.1.4 Analytical Column—Anion exchange column capable
anions in the eluent.
of separating the ions of interest from each other, as well as
The separated anions in the eluent stream then pass through
from other ions which commonly occur in the sample matrix,
a suppressor device, where all cations are exchanged for
e.g., Dionex IonPac AS9-HC (4 mm ID), or equivalent. The
hydronium ions.This converts the eluent to carbonic acid, thus
separation shall be at least as good as that shown in Fig. 2.The
reducing the background conductivity. This process also con-
use of 2 mm IDAS9-HC column, in conjunction with a 50 µL
verts the sample anions to their acid form, thus enhancing their
sample loop, may improve the peak shape for early eluting
conductivity. The eluent stream then passes through a conduc-
anions, such as chlorite and bromate.
tivity cell, where they are detected. A chromatographic inte-
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.
baselineresolutionofallanions,evenfora200µLinjectioncontainingup
to 200 mg/L, each, of common anions, such as chloride, bicarbonate, and
4.2 The anions are identified based on their retention times
sulfate.
compared to known standards. Quantification is accomplished
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
provided that comparable method detection limits are achieved
5.1 The oxyhalides chlorite, chlorate, and bromate are
inorganic disinfection by-products (DBPs) of considerable and that adequate baseline stability is attained.
7.1.6 Conductivity Detector—A low-volume, flow through,
health risk concern worldwide. The occurrence of chlorite and
chlorate is associated with the use of chlorine dioxide, as well temperaturestabilized conductivity cell equipped with a meter
capable of reading from 0 to 1000 µS/cm on a linear scale.
as hypochlorite solutions used for drinking water disinfection.
The occurrence of bromate is associated with the use of ozone 7.1.7 Data System—A chromatographic integrator or
computer-based data system capable of graphically presenting
for disinfection, wherein naturally occurring bromide is oxi-
the detector output signal versus time, as well as presenting the
dized to bromate. Bromide is a naturally occurring precursor to
integrated peak areas.
the formation of bromate.
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-
towatershallbeunderstoodtomeanreagentwaterconforming
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,
injector, syringes, columns, suppressor, conductivity detector,
“Reagent Chemicals,American Chemical Society Specifications,”Am. Chemi-
data system and compressed gasses.
cal Soc., Washington, DC. For suggestions on the testing of reagents not listed by
7.1.1 Eluent Pump—capableofdelivering0.25to5mL/min
theAmerican Chemical Society, see “Analar Standards for Laboratory Chemicals,”
of eluent at a pressure of up to 4000 psi. by BDH Ltd., Poole, Dorset, U.K., and the “United States Pharmacopoeia.”
D 6581–00 (2005)
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.
8.4 Eluent, Analysis (9.0 mM Sodium Carbonate)—Dilute 8.5 Ethylenediamine (EDA) Preservation Solution (50.0
100.0 mL of Eluent Concentrate (8.3) to 1.000 L with water. g/L)—Dilute 11.2 mL of ethylenediamine (99%) to 200 mL
8.4.1 The Eluent Analysis solution (9.0 mM Sodium Car-
with reagent water. Prepare this solution fresh monthly. Add
bonate)mustbepurgedfor10minuteswithheliumpriortouse
1.00 mL of this solution per 1.000 L of blank, standard or
to remove dissolved gasses in order to ensure optimal system
sample to produce a final EDA concentration of 50 mg/L.
performance.
D 6581–00 (2005)
A
TABLE 1 Instrumentation and Operating Conditions for the
8.6 SPE Sample Preatment Cartridges— Chloride present
Determination of Oxyhalides and Bromide and by Ion
at > 200 mg/L and carbonate present at > 300 mg/L can
Chromatography, as shown in Figs. 1 and 2
+ +
interfere with bromate determination. H form and Ag form
Ion Chromatograph DX-500 (or equivalent)
cation exchange SPE cartridges can be used to minimize the
Guard Column IonPac AG9-HC, (or equivalent)
carbonate and chloride interferences, respectively, if required.
Analytical Column IonPac AS9-HC, (or equivalent)
Eluent 9.0 mM Sodium carbonate
Dionex OnGuard-H and OnGuard-Ag cartridges have been
5 Flow-Rate 1.0 mL/min.
shown to be suitable for this application. The use of these
Injection volume 200 µL
pretreatment cartridges will effect recoveries for bromide,
Suppressor ASRS-ULTRA, (or equivalent), 100mA in external
water mode at 10 mL/min.
requiring that it be analyzed in a separate run.
Detector CD20 Conductivity Detector (or equivalent), stabilized
8.7 Suppressor Regenerant Solution— If a suppressor re-
at 35°C
quiring chemical regeneration is used, the regenerant solution
A
Dionex Corporation, Sunnyvale, CA.
is prepared by cautiously adding 3.00 mL of concentrated
sulfuric acid (sp. gr. 1.84) to 4.000 Lof water. If anAnion Self
sample to prevent conversion of residual hypochlorite or
Regenerating Suppressor is used, it should be operated in the
external water mode. hypobromite to chlorate or bromate. This also prevents metal
8.8 Standard Solutions, Stock (1.00 mL = 1.00 mg)— catalyzed conversion of chlorite to chlorate. The oxyhalides in
Purchase certified solutions or prepare stock standard solutions samples preserved in this manner are stable for at least 14 days
from the following salts, as described below: when stored in amber bottles at 4°C.
—
8.8.1 Bromate (BrO ) Solution, Stock (1.00 mL = 1.00 mg
—
11. Quality Control
BrO )—Dissolve 1.180 g of sodium bromate (NaBrO)in
3 3
water and dilute to 1.000 L.
11.1 Before this test is applied to analyzing unknown
—
8.8.2 Bromide (Br ) Solution, Stock (1.00 mL = 1.00 mg
samples, the analyst should establish quality control proce-
—
Br )—Dissolve 1.288 g of sodium bromide (NaBr) in water
dures as recommended in Guide D 3856.
and dilute to 1.000 L.
11.2 The laboratory using this test should perform an initial
—
8.8.3 Chlorate (ClO ) Solution, Stock (1.00 mL = 1.00 mg demonstration of laboratory capability. Analyze seven repli-
—
C1O )—Dissolve 1.275 g of sodium chlorate (NaClO)in
cates of an Initial Demonstration of Performance (IDP) solu-
3 3
water and dilute to 1.000 L. tion. The IDP solution contains method analytes of known
—
8.8.4 Chlorite (ClO ) Solution, Stock (1.00 mL = 1.00 mg
concentration, prepared from a different source to the calibra-
—
ClO )—Dissolve 1.680 g of sodium chlorite (NaClO)in tion standards, used to fortify reagent water, which also
2 2
water and dilute to 1.000 L. Note that as sodium chlorite is
contains a final EDA concentration of 50 mg/L (8.5
...
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