ASTM D512-23

Standard Test Methods for Chloride Ion In Water

SIGNIFICANCE AND USE
4.1 Chloride ion is under regulation in waste water, and must, therefore, be measured accurately. It is highly detrimental to high-pressure boiler systems and to stainless steel, so monitoring is essential for prevention of damage. Chloride analysis is widely used as a tool for estimating the cycles of concentration, such as in cooling tower applications. Processing waters and pickling solutions used in the food processing industries also require dependable methods of analysis for chloride.
SCOPE
1.1 These test methods cover the determination of chloride ion in water, wastewater (Test Method C only), and brines. The following three test methods are included:    
Sections    
Test Method A (Mercurimetric Titration)  
7 to14  
Test Method B (Silver Nitrate Titration)  
15 to 21  
Test Method C (Ion-Selective Electrode Method)  
22 to 29  
1.2 Test Methods A, B, and C were validated under Practice D2777 – 77, and only Test Method B conforms also to Practice D2777 – 86. Refer to Sections 14, 21, and 29 for further information.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see 26.1.1.  
1.5 A former colorimetric test method was discontinued. Refer to Appendix X1 for historical information.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Mar-2023
• ICS: 13.060.50 - Examination of water for chemical substances
• Technical Committee: D19 - Water
• Drafting Committee: D19.05 - Inorganic Constituents in Water

Relations

• Refers: ASTM D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM D1066-18 - Standard Practice for Sampling Steam
• Effective Date: 01-Aug-2018
• Refers: ASTM D1066-18e1 - Standard Practice for Sampling Steam
• Effective Date: 01-Aug-2018
• Refers: ASTM D4127-18 - Standard Terminology Used with Ion-Selective Electrodes
• Effective Date: 01-Feb-2018
• Refers: ASTM D4127-12 - Standard Terminology Used with Ion-Selective Electrodes
• Effective Date: 01-Aug-2012
• Refers: ASTM D2777-12 - Standard Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
• Effective Date: 15-Jun-2012
• Refers: ASTM D1066-11 - Standard Practice for Sampling Steam
• Effective Date: 15-Jun-2011
• Refers: ASTM D5810-96(2011) - Standard Guide for Spiking into Aqueous Samples
• Effective Date: 01-May-2011
• Refers: ASTM D3370-10 - Standard Practices for Sampling Water from Closed Conduits
• Effective Date: 01-Dec-2010
• Refers: ASTM D1129-10 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2010
• Refers: ASTM D3370-08 - Standard Practices for Sampling Water from Closed Conduits
• Effective Date: 01-Oct-2008
• Refers: ASTM D2777-08 - Standard Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
• Effective Date: 15-Jan-2008
• Refers: ASTM D3370-07 - Standard Practices for Sampling Water from Closed Conduits
• Effective Date: 01-Dec-2007
• Refers: ASTM D4127-06 - Standard Terminology Used with Ion-Selective Electrodes
• Effective Date: 15-Dec-2006
• Refers: ASTM D1066-06 - Standard Practice for Sampling Steam
• Effective Date: 15-Dec-2006

Overview

ASTM D512-23: Standard Test Methods for Chloride Ion in Water provides established procedures for accurately determining chloride ion concentrations in various water samples. Chloride analysis is a critical requirement across multiple industries due to its regulatory implications and potential to cause damage in high-pressure boilers and stainless steel infrastructure. The standard outlines three validated test methods - mercurimetric titration, silver nitrate titration, and ion-selective electrode analysis - covering a wide range of sample types including water, wastewater, and brines.

The accurate measurement of chloride ions is essential for regulatory compliance in wastewater management, prevention of corrosion in industrial systems, and optimizing cycles of concentration in applications such as cooling towers. This ASTM standard supports analytical reliability by specifying reagent quality, sample collection protocols, and robust quality control measures, ensuring consistent and reproducible results.

Key Topics

• Regulatory Compliance: Chloride ion concentration in wastewater is regulated, making precise quantification a legal and operational necessity.
• Damage Prevention: Chlorides are highly detrimental to high-pressure boilers and stainless steel equipment, necessitating regular monitoring to prevent costly failures and corrosion.
• Industrial Water Management: The analysis is integral in monitoring cycles of concentration in cooling towers and ensuring the integrity of water used in food processing and pickling operations.
• Multiple Analytical Methods:
  • Mercurimetric Titration (Method A): Suited for general water analysis where interferences are minimal.
  • Silver Nitrate Titration (Method B): Preferred in samples with higher interference or color.
  • Ion-Selective Electrode (Method C): Applicable to a broad range of water types, including wastewater, for rapid and versatile analysis.

Applications

ASTM D512-23 is utilized in a variety of industry sectors and laboratory environments, including:

• Water Treatment Facilities: For routine monitoring of potable, process, and wastewater streams, ensuring discharge and reuse water meets chloride limits.
• Industrial Systems: Protecting boilers, cooling towers, and other water-using equipment from chloride-induced corrosion, scaling, and failure.
• Environmental Laboratories: Supporting compliance with environmental regulations and permit requirements for effluent discharge.
• Food and Beverage Industry: Maintaining product quality and compliance in processes involving brines and pickling solutions.
• Quality Assurance Laboratories: Conducting validation studies and proficiency testing as part of laboratory accreditation and regulatory reporting.

The inclusion of multiple test methods in ASTM D512-23 allows laboratories to select the most suitable approach based on sample matrix, expected chloride levels, and available instrumentation.

Related Standards

Professionals implementing ASTM D512-23 often reference the following related ASTM standards for terminology, sampling, and reagent specifications:

• ASTM D1129: Terminology Relating to Water
• ASTM D1193: Specification for Reagent Water
• ASTM D2777: Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
• ASTM D3370: Practices for Sampling Water from Flowing Process Streams
• ASTM D4127: Terminology Used with Ion-Selective Electrodes
• ASTM D5810: Guide for Spiking into Aqueous Samples
• ASTM D5847: Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis
• ASTM E200: Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis

Practical Value

By following ASTM D512-23, organizations can ensure high-quality water analysis, support robust environmental stewardship, maintain regulatory compliance, and minimize equipment risk. The standard's versatility in methods fits diverse analytical needs while maintaining a focus on precision, accuracy, and safety in chloride determination for water and wastewater systems.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D512 − 23
Standard Test Methods for
Chloride Ion In Water
This standard is issued under the fixed designation D512; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
1.1 These test methods cover the determination of chloride
D2777 Practice for Determination of Precision and Bias of
ion in water, wastewater (Test Method C only), and brines. The
Applicable Test Methods of Committee D19 on Water
following three test methods are included:
D3370 Practices for Sampling Water from Flowing Process
Sections
Streams
Test Method A (Mercurimetric Titration) 7 to14
D4127 Terminology Used with Ion-Selective Electrodes
Test Method B (Silver Nitrate Titration) 15 to 21
D5810 Guide for Spiking into Aqueous Samples
Test Method C (Ion-Selective Electrode Method) 22 to 29
D5847 Practice for Writing Quality Control Specifications
1.2 Test Methods A, B, and C were validated under Practice
for Standard Test Methods for Water Analysis
D2777 – 77, and only Test Method B conforms also to Practice
E200 Practice for Preparation, Standardization, and Storage
D2777 – 86. Refer to Sections 14, 21, and 29 for further
of Standard and Reagent Solutions for Chemical Analysis
information.
1.3 The values stated in SI units are to be regarded as
3. Terminology
standard. No other units of measurement are included in this
3.1 Definitions—For definitions of terms used in these test
standard.
methods, refer to Terminologies D1129 and D4127.
1.4 This standard does not purport to address all of the
4. Significance and Use
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4.1 Chloride ion is under regulation in waste water, and
priate safety, health, and environmental practices and deter-
must, therefore, be measured accurately. It is highly detrimen-
mine the applicability of regulatory limitations prior to use.
tal to high-pressure boiler systems and to stainless steel, so
For a specific hazard statement, see 26.1.1.
monitoring is essential for prevention of damage. Chloride
1.5 A former colorimetric test method was discontinued.
analysis is widely used as a tool for estimating the cycles of
Refer to Appendix X1 for historical information.
concentration, such as in cooling tower applications. Process-
ing waters and pickling solutions used in the food processing
1.6 This international standard was developed in accor-
industries also require dependable methods of analysis for
dance with internationally recognized principles on standard-
chloride.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
5. Purity of Reagents
mendations issued by the World Trade Organization Technical
5.1 Reagent grade chemicals shall be used in all tests.
Barriers to Trade (TBT) Committee.
Unless otherwise indicated, it is intended that all reagents shall
2. Referenced Documents
conform to the specifications of the Committee on Analytical
Reagents of the American Chemical Society, where such
2.1 ASTM Standards:
D1066 Practice for Sampling Steam specifications are available. Other grades may be used, pro-
vided it is first ascertained that the reagent is of sufficiently
These test methods are under the jurisdiction of ASTM Committee D19 on high purity to permit its use without lessening the accuracy of
Water and are the direct responsibility of Subcommittee D19.05 on Inorganic
the determination.
Constituents in Water.
Current edition approved April 1, 2023. Published April 2023. Originally
approved in 1938. Last previous edition approved in 2012 as D512 – 12 which was ACS Reagent Chemicals, Specifications and Procedures for Reagents and
withdrawn July 2021 and reinstated in April 2023. DOI: 10.1520/D0512-23. Standard-Grade Reference Materials, American Chemical Society, Washington,
For referenced ASTM standards, visit the ASTM website, www.astm.org, or DC. For suggestions on the testing of reagents not listed by the American Chemical
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
Standards volume information, refer to the standard’s Document Summary page on U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
the ASTM website. copeial Convention, Inc. (USPC), Rockville, MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D512 − 23
5.2 Purity of Water—Unless otherwise indicated, references 11.1 Hydrogen Peroxide (30 % H O ).
2 2
to water shall be understood to mean Type I reagent water
11.2 Hydroquinone Solution (10 g/L)—Dissolve 1 g of
conforming to Specification D1193. Other reagent water types
purified hydroquinone in water and dilute to 100 mL.
may be used provided it is first ascertained that the water is of
11.3 Mercuric Nitrate Solution, Standard (0.0125M;
sufficiently high purity to permit its use without adversely
0.025N)—Dissolve 4.2830 g of mercuric nitrate
affecting the precision and bias of the test method. Type II
(Hg(NO ) ·H O) in 50 mL of water acidified with 0.5 mL of
3 2 2
water was specified at the time of round robin testing of this
concentrated nitric acid (HNO , sp gr 1.42). Dilute the acidi-
test method.
fied Hg(NO ) solution with water to 1 L. Filter if necessary,
3 2
6. Sampling and standardize against the standard sodium chloride (NaCl)
solution, using the procedure described in Section 12 (see Note
6.1 Collect the sample in accordance with Practice D1066
2).
and Practices D3370, as applicable.
NOTE 2—Sharpness of End Point—The end point, while sharp, can be
TEST METHOD A—MERCURIMETRIC
improved somewhat for certain types of water by adding several drops of
TITRATION a 0.05-g/L solution of xylene cyanole FF or alphazurine blue-green dye
(color index 714) to the titration sample.
7. Scope
11.4 Mixed Indicator Solution —Dissolve 0.5 g of crystal-
7.1 This test method can be used to determine chloride ion
line diphenylcarbazone and 0.05 g of bromophenol blue
in water, provided interferences are absent (see Section 9).
powder in 75 mL of ethyl alcohol (95 %), and dilute to 100 mL
with the alcohol (Note 3). Store in a brown bottle and discard
7.2 Though not specified in the research report, the preci-
after 6 months (Note 4).
sion statement is presumed to have been obtained using Type II
reagent water. It is the responsibility of the analyst to assure the
NOTE 3—Methanol, isopropanol, or ethanol denatured with either
validity of this test method for untested matrices. methanol or isopropanol (Formula 3A) may be used if pure ethyl alcohol
is not available. Other denatured ethanol formulae are not suitable.
7.3 This test method was validated for the concentration
NOTE 4—Liquid indicator generally deteriorates to the point that it
−
range 8.0 to 250 mg/L Cl .
yields no end-point color after 12 to 18 months of storage. High
temperature (above 37.8 °C (100 °F)) and exposure to bright light may
8. Summary of Test Method
shorten storage life. A dry powder mixture of the two indicator ingredients
is stable for much longer periods. Both the powder mixture (capsule form)
8.1 Dilute mercuric nitrate solution is added to an acidified
and the liquid indicator are available commercially.
sample in the presence of mixed diphenylcarbazone-
11.5 Nitric Acid (3 + 997)—Mix 3 volumes of concentrated
bromophenol blue indicator. The end point of the titration is the
nitric acid (HNO , sp gr 1.42) with 997 volumes of water.
formation of the blue-violet mercury diphenylcarbazone com-
plex. 11.6 pH Indicating Paper, long-range type, covering a pH
range 1 to 11.
9. Interferences
11.7 Sodium Chloride Solution, Standard (0.025N)—
9.1 The anions and cations generally found in water offer no
Purchase a commercially available standard or prepare as
interference. Zinc, lead, nickel, and ferrous and chromous ions
follows: Dry several grams of reagent grade sodium chloride
affect solution and end-point colors, but do not reduce the
(NaCl) for 2 h at 110 °C. Dissolve 1.4613 g of the dry salt in
accuracy of the titration when present in concentrations up to
water, and dilute to 1 L at 25 °C in a volumetric flask.
100 mg/L. Copper is tolerable up to 50 mg/L. Titration in the
11.8 Sodium Hydroxide Solution (10 g/L)—Dissolve 10 g of
presence of chromate ion requires indicator with extra back-
sodium hydroxide (NaOH) in water and dilute to 1 L.
ground color (alphazurine) and prior reduction for concentra-
tions above 100 mg/L. Ferric ion above 10 mg/L must be
12. Procedure
reduced before titration, and sulfite ion must be oxidized.
Bromide, iodide, and fluoride will be titrated or partially 12.1 Use a volume of sample such that it will contain not
titrated with the chloride. Quaternary ammonium salts also more than 20 mg of chloride ion, diluting the sample with
interfere if present in significant amounts (1 to 2 mg/L). Deep water to approximately 50-mL volume if necessary. Determine
color may also interfere. an indicator blank on 50 mL of chloride-free water, applying
the same procedure followed for the sample.
10. Apparatus
12.2 Add 5 to 10 drops of mixed indicator solution, and
10.1 Microburet, 1 or 5-mL, with 0.01-mL graduation
shake or swirl the flask. If a blue-violet or red color develops,
intervals.
add HNO (3 + 997) dropwise until the color changes to
yellow. Add 1 mL of excess acid. If a yellow or orange color
11. Reagents and Materials
forms immediately on addition of the mixed indicator, add
NOTE 1—Consult the manufacturer Material Safety Data Sheet for safe
NaOH solution (10 g/L) dropwise until the color changes to
work practices before working with reagents.
For information of interest in connection with this test method, and supporting
data, refer to Clark, F. E., “Determination of Chloride in Water,” Analytical This diphenylcarbazone 1-bromophenol blue indicator is covered by U.S.
Chemistry, Vol 22, April 1950, pp. 553–555, and Vol 22, November 1950, p. 1458. Patent No. 2,784,064.
D512 − 23
blue-violet; then add HNO (3 + 997) dropwise until the color 14. Precision and Bias
changes to yellow and further add 1 mL excess of acid (Note
14.1 Precision Statement—The precision of this test method
5).
may be expressed as follows:
NOTE 5—The prescribed acidification provides a satisfactory pH range
S 5 0.023X10.43
T
from 3.0 to 3.5. Acidified samples on which electrometric pH measure-
S 5 0.002X10.46
ments have been made can be used for chloride determinations only if the
O
pH electrode fill solution contains no chloride, for example, use a pH half
where:
cell and a double junction reference electrode with a sodium nitrate outer
fill solution. Alternately, for precise pH adjustment of samples having a
S = overall precision, mg/L,
T
low-chloride concentration, instrumental measurements may be made on
S = single-operator precision, mg/L, and
O
one sample aliquot to determine treatment needed for another to be used
X = concentration of chloride ion determined.
for the chloride test.
14.2 Bias Statement—Recoveries of known amounts of
12.3 Titrate the solution and a blank with 0.025 N Hg(NO )
3 2
chloride were as follows:
solution until a blue-violet color, as viewed by transmitted
Statistically
light, persists throughout the solution (Note 6). Record the
Amount Added, Amount Found, Significant (95 %
millilitres of Hg(NO ) solution added in each case.
3 2
mg/L mg/L ± % Bias Confidence Level)
250 248 −0.80 no
NOTE 6—The use of indicator modifications and the presence of heavy
80.0 79.3 −0.88 no
metal ions can change solution colors without affecting accuracy of the
8.00 7.51 −6.13 yes
determination. For example, solutions containing alphazurine may be
bright blue when neutral, grayish purple when basic, blue-green when 14.3 The information presented in 14.1 and 14.2 is derived
acidic, and blue-violet at the chloride end point. Solutions containing
from round-robin testing in which five laboratories, including
about 100 mg/L nickel ion and normal mixed indicator are purple when
seven operators, participated. Though not clearly specified in
neutral, green when acid, and gray at the chloride end point. When
the test report, the matrix is presumed to be Type II reagent
applying this test method to samples that contain colored ions or that
water. Of seven data sets ranked as described in Practice
require modified indicator, it is recommended that the operator be familiar
with the specific color changes involved by experimenting with solutions
D2777, none was rejected, nor were any data points determined
prepared as standards for comparison of color effects.
to be “outliers.” Three sample levels were run on at least three
days. The method of “least squares” was used to determine the
12.4 If chromate ion is present in the absence of iron and in
precision statement, with correlation of 0.7394 for S and
concentration less than 100 mg/L, use the alphazurine modified
O
0.9993 for S .
mixed indicator (Note 2) and acidify the sample as described in
T
12.2 but to pH 3 as indicated by pH indicating paper. Titrate the
14.4 It is the responsibility of the analyst to assure the
solution as described in 12.3, but to an olive-purple end point.
validity of this test method for untested matrices.
12.5 If chromate ion is present in the absence of iron and in
14.5 Precision and bias for this test method conforms to
concentration greater than 100 mg/L, add 2 mL of fresh
Practice D2777 – 77, which was in place at the time of
hydroquinone solution and proceed as described in 12.2 and
collaborative testing. Under the allowances made in 1.5 of
12.3.
Practice D2777 – 08, these precision and bias data do meet
12.6 If ferric ion is present in the absence or presence of
existing requirements for interlaboratory studies of Committee
chromate ions, use a sample of such volume as to contain no
D19 test methods.
more than 2.5 mg of ferric ion or of ferric ion plus chromate
TEST METHOD B—SILVER NITRATE TITRATION
ion. Add 2 mL of fresh hydroquinone solution, and proceed as
described in 12.2 and 12.3.
15. Scope
12.7 If sulfite ion is present, add 0.5 mL of H O to 50 mL
2 2
of the sample in the Erlenmeyer flask and mix for 1 min. Then 15.1 This test method is intended primarily for water where
the chloride content is 5 mg/L or more, and where interferences
proceed as described in 12.2 and 12.3.
such as color or high concentrations of heavy metal ions render
13. Calculation
Test Method A impracticable.
13.1 Calculate the chloride ion concentration, in milligrams
15.2 Though not specified in the research report, the preci-
per litre, in the original sample as follows:
sion and bias statement is presumed to have been obtained
Chloride, mg/L 5 V 2 V × N × 35 453 /S using Type II reagent water. It is the responsibility of the
@~ ! #
S b
analyst to assure the validity of this test method for untested
where:
matrices.
V = standard Hg(NO ) solution required for titration
S 3 2
15.3 This test method was validated for the concentration
of the sample, mL,
−
range 8.0 to 250 mg/L Cl .
V = standard Hg(NO ) solution required for titration
b 3 2
of the blank, mL,
N = normality of the Hg(NO ) solution (see Note 7),
3 2
S = sample used in 12.1, mL, and
Supporting data have been filed at ASTM International Headquarters and may
35 453 = 35.453 g/mole chloride * 1000 mg/g.
be obtained by requesting Research Report RR:D19-1076. Contact ASTM Customer
NOTE 7—The normality of the mercuric nitrate solution standard is Service at [e-mail].
based on a 2:1 (Cl:Hg) reaction. Mohr, F., ANN., 97, 335 (1856).
D512 − 23
16. Summary of Test Method 19.3 Repeat the procedure described in 19.1 and 19.2, using
exactly one half as much original sample, diluted to 50 mL
16.1 Water adjusted to approximately pH 8.3 is titrated with
with water.
silver nitrate solution in the presence of potassium chromate
19.4 If the volume of titrant used in 19.3 is one-half of that
indicator. The end point is indicated by persistence of the
used in titrating the aliquot in 19.1, proceed to the calculation
brick-red silver chromate color.
section. If not, significant interferences are present and com-
pensation must be made; alternatively, another method must be
17. Interferences
used.
17.1 Bromide, iodide, and sulfide are titrated along with the
chloride. Orthophosphate and polyphosphate interfere if pres-
20. Calculation
ent in concentrations greater than 250 and 25 mg/L, respec-
20.1 Calculate the chloride ion concentration in the original
tively. Sulfite and objectionable color or turbidity must be
sample, in milligrams per litre as follows:
eliminated. Compounds which precipitate at pH 8.3 (certain
hydroxides) may cause error by occlusion.
Chloride, mg/L 5 @~V 2 V ! × N × 70906#/S
1 2
where:
18. Reagents
V = standard solution AgNO added in titrating the
1 3
18.1 Hydrogen Peroxide (30 %) (H O ).
2 2
original sample, S, as prepared in 19.1, mL,
V = standard solution, AgNO added in titrating one-
2 3
18.2 Phenolphthalein Indicator Solution (10 g/L)—Prepare
half the volume of the original sample, as prepared
as directed in Practice E200.
in 19.3, mL,
18.3 Potassium Chromate Indicator Solution—Dissolve 50
N = normality of standard AgNO solution (see Note 9),
g of potassium chromate (K CrO ) in 100 mL of water, and add
S = original sample in the 50-mL test specimen pre-
2 4
silver nitrate (AgNO ) until a slight red precipitate is produced. pared in 19.1, mL, and
Allow the solution to stand, protected from light, for at least 24 70906 = 35.453 g/mole chloride * 2 * 1000 mg/g, where the
h after the addition of AgNO . Then filter the solution to factor of 2 accounts for one-half the sample volume
remove the precipitate, and dilute to 1 L with water. (19.3).
NOTE 9—The normality calculation is based on a 1:1 (Cl:Ag) reaction.
18.4 Standard Solution, Silver Nitrate (0.025M; 0.025 N)—
Crush approximately 5 g of silver nitrate (AgNO ) crystals and 6
21. Precision and Bias
dry to constant weight at 40°C. Dissolve 4.2473 g of the
21.1 Precision—The precision of this test method may be
crushed, dried crystals i
...