ASTM D3866-18

Standard Test Methods for Silver in Water

SIGNIFICANCE AND USE
4.1 The principal adverse effect of silver in the body is cosmetic. It causes argyria, a permanent, blue-gray discoloration of the skin, eyes, and mucous membranes.  
4.2 Relatively small quantities of silver are bactericidal or bacteriostatic and find limited use in both disinfection of swimming pool waters and point-of-use water filters.  
4.3 ICP-MS or ICP-AES may also be appropriate but at a higher instrument cost. See Test Methods D5673 and D1976.
SCOPE
1.1 These test methods cover the atomic absorption determination of silver in water. Section 34 on Quality Control pertains to these test methods. Three test methods are given as follows:    
Concentration
Range  
Sections  
Test Method A—Atomic Absorption—Chelation-ExtractionA  
1 to 10 μg/L  
7 – 15  
Test Method B—Atomic Absorption—Direct  
0.1 to 10 mg/L  
16 – 24  
Test Method C—Atomic Absorption—Graphite Furnace  
1 to 25 μg/L  
25 – 33(A) Similar to that in Brown, E., Skougstad, M. W., and Fishman, M. J., “Methods for Collection and Analysis of Water Samples for Dissolved Minerals and Gases,” Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book 5, Chapter A1, 1970, p. 46.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversion to inch-pound units that are provided for information only and are not considered standard.  
1.3 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. Specific precautionary statements are given in 11.5, 11.12.1, 13.8, and 22.1.  
1.4 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-Jan-2018
• ICS: 13.060.50 - Examination of water for chemical substances
• Technical Committee: D19 - Water
• Drafting Committee: D19.05 - Inorganic Constituents in Water

Relations

• Replaces: ASTM D3866-12 - Standard Test Methods for Silver in Water
• Effective Date: 01-Feb-2018
• Refers: ASTM D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM D1976-20 - Standard Test Method for Elements in Water by Inductively-Coupled Plasma Atomic Emission Spectroscopy
• Effective Date: 01-May-2020
• Refers: ASTM D1976-18 - Standard Test Method for Elements in Water by Inductively-Coupled Plasma Atomic Emission Spectroscopy
• Effective Date: 01-Jul-2018
• Refers: ASTM D5673-15 - Standard Test Method for Elements in Water by Inductively Coupled Plasma—Mass Spectrometry
• Effective Date: 01-Jul-2015
• Refers: ASTM D4841-88(2013)e1 - Standard Practice for Estimation of Holding Time for Water Samples Containing Organic and Inorganic Constituents
• Effective Date: 01-Jan-2013
• Refers: ASTM D4841-88(2013) - Standard Practice for Estimation of Holding Time for Water Samples Containing Organic and Inorganic Constituents
• Effective Date: 01-Jan-2013
• 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 D1976-12 - Standard Test Method for Elements in Water by Inductively-Coupled Argon Plasma Atomic Emission Spectroscopy
• Effective Date: 01-Mar-2012
• Refers: ASTM D4691-11 - Standard Practice for Measuring Elements in Water by Flame Atomic Absorption Spectrophotometry
• Effective Date: 01-Sep-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 D5673-10 - Standard Test Method for Elements in Water by Inductively Coupled Plasma-Mass Spectrometry
• Effective Date: 01-Aug-2010
• Refers: ASTM D1129-10 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2010
• Refers: ASTM D3919-08 - Standard Practice for Measuring Trace Elements in Water by Graphite Furnace Atomic Absorption Spectrophotometry
• Effective Date: 15-Nov-2008

Overview

ASTM D3866-18: Standard Test Methods for Silver in Water establishes precise methods for the determination of silver concentrations in various types of water, including drinking, natural, surface, and wastewaters. Silver, though used for its bactericidal properties, can pose health concerns, most notably the cosmetic condition argyria - a blue-gray discoloration of the skin and mucous membranes. Silver’s presence in water must therefore be monitored both for regulatory compliance and public health protection. This standard supports environmental monitoring, industrial quality control, and research applications by providing reliable procedures to detect trace and higher levels of silver using atomic absorption techniques.

Key Topics

• Scope of the Standard
  ASTM D3866-18 details three test methods for determining silver concentrations, accommodating a wide range of detection needs:

  • Atomic Absorption-Chelation-Extraction (Test Method A): 1 to 10 μg/L
  • Atomic Absorption-Direct (Test Method B): 0.1 to 10 mg/L
  • Atomic Absorption-Graphite Furnace (Test Method C): 1 to 25 μg/L

• Sample Collection and Preservation
  The standard outlines proper sample collection (referencing ASTM D3370), preservation techniques (e.g., acidification and filtration), and required reagent purity to mitigate contamination and ensure accuracy.

• Quality Control
  The document includes robust quality control measures:

  • Use of calibration standards and blanks for each run
  • Verification of calibration with mid-range standards
  • Routine laboratory control samples and method blanks
  • Initial laboratory capability demonstration with control samples

• Significance and Use

  • Addresses health implications of silver in water
  • Recognizes silver’s utility for disinfection while highlighting the need to limit exposure
  • Notes alternative, advanced test methods like ICP-MS or ICP-AES for laboratories with suitable resources

Applications

• Drinking Water Monitoring
  Public health authorities and utilities use these methods to ensure silver concentrations remain below thresholds that could cause argyria or other concerns.

• Environmental Compliance
  Water treatment plants, environmental agencies, and industrial facilities apply these test methods to meet regulatory requirements for effluent and process water, protecting both consumers and ecosystems.

• Product Quality Control
  Manufacturers of water filtration systems - especially those using silver as a bacteriostatic agent - rely on these methods to verify product safety and performance.

• Research and Analytical Laboratories
  These methods are fundamental for studies related to water quality, environmental impact assessments, and method development for trace metals analysis.

Related Standards

• ASTM D1129: Terminology Relating to Water
• ASTM D1193: Specification for Reagent Water
• ASTM D1976 & D5673: Test methods using inductively coupled plasma techniques for element analysis in water
• ASTM D2777: Practices for determination of precision and bias in water test methods
• ASTM D3370: Practices for sampling water from closed conduits
• ASTM D3919 & D4691: Practices for atomic absorption spectrophotometry in water analysis
• ASTM D4841, D5810, D5847: Additional guidance on holding time, spiking samples, and quality control procedures

Summary

ASTM D3866-18 provides a comprehensive framework for the reliable detection and quantification of silver in water, ensuring laboratories can meet regulatory, environmental, and public health objectives. By adhering to standardized methods and quality control protocols, users can be confident in the accuracy of their results when analyzing for silver in diverse water matrices.

Keywords: ASTM D3866, silver in water, silver testing, atomic absorption, water quality analysis, argyria, quality control, ASTM standards, water sampling, trace metals analysis.

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: D3866 − 18
Standard Test Methods for
Silver in Water
This standard is issued under the fixed designation D3866; 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.
1. Scope* 2. Referenced Documents
1.1 These test methods cover the atomic absorption deter- 2.1 ASTM Standards:
mination of silver in water. Section 34 on Quality Control D1129 Terminology Relating to Water
pertains to these test methods. Three test methods are given as D1193 Specification for Reagent Water
follows: D1976 Test Method for Elements in Water by Inductively-
Coupled Argon Plasma Atomic Emission Spectroscopy
Concentration
Range Sections
D2777 Practice for Determination of Precision and Bias of
Applicable Test Methods of Committee D19 on Water
Test Method A—Atomic Absorption— 1to10µg/L 7–15
A
D3370 Practices for Sampling Water from Closed Conduits
Chelation-Extraction
Test Method B—Atomic Absorption— 0.1to10mg/L 16–24
D3919 Practice for Measuring Trace Elements in Water by
Direct
Graphite Furnace Atomic Absorption Spectrophotometry
Test Method C—Atomic Absorption— 1to25µg/L 25–33
D4691 Practice for Measuring Elements in Water by Flame
Graphite Furnace
Atomic Absorption Spectrophotometry
A
Similar to that in Brown, E., Skougstad, M. W., and Fishman, M. J., “Methods for
D4841 Practice for Estimation of Holding Time for Water
Collection and Analysis of Water Samples for Dissolved Minerals and Gases,”
Samples Containing Organic and Inorganic Constituents
Techniques of Water-Resources Investigations of the U.S. Geological Survey,
D5673 Test Method for Elements in Water by Inductively
Book 5, Chapter A1, 1970, p. 46.
Coupled Plasma—Mass Spectrometry
1.2 The values stated in SI units are to be regarded as
D5810 Guide for Spiking into Aqueous Samples
standard. The values given in parentheses are mathematical
D5847 Practice for Writing Quality Control Specifications
conversion to inch-pound units that are provided for informa-
for Standard Test Methods for Water Analysis
tion only and are not considered standard.
3. Terminology
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1 Definitions:
responsibility of the user of this standard to establish appro-
3.1.1 For definitions of terms used in this standard, refer to
priate safety, health, and environmental practices and deter-
Terminology D1129.
mine the applicability of regulatory limitations prior to use.
3.2 Definitions of Terms Specific to This Standard:
Specific precautionary statements are given in 11.5, 11.12.1,
3.2.1 laboratory control sample, n—a solution with a certi-
13.8, and 22.1.
fied concentration of silver.
1.4 This international standard was developed in accor-
3.2.2 total recoverable silver, n—a descriptive term relating
dance with internationally recognized principles on standard-
toformsofsilverthataredeterminablebythedigestionmethod
ization established in the Decision on Principles for the
that is included in these test methods.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4. Significance and Use
Barriers to Trade (TBT) Committee.
4.1 The principal adverse effect of silver in the body is
cosmetic. It causes argyria, a permanent, blue-gray discolor-
ation of the skin, eyes, and mucous membranes.
These test methods are under the jurisdiction of ASTM Committee D19 on
Water and are the direct responsibility of Subcommittee D19.05 on Inorganic
Constituents in Water. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2018. Published March 2018. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1979. Last previous edition approved in 2012 as D3866 – 12. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D3866-18. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3866 − 18
4.2 Relatively small quantities of silver are bactericidal or TEST METHOD A—ATOMIC ABSORPTION—
bacteriostatic and find limited use in both disinfection of CHELATION EXTRACTION
swimming pool waters and point-of-use water filters.
7. Scope
4.3 ICP-MS or ICP-AES may also be appropriate but at a
7.1 This test method covers the determination of dissolved
higher instrument cost. See Test Methods D5673 and D1976.
and total recoverable silver in most water and wastewaters.
5. Purity of Reagents 7.2 This test method is applicable in the range from 1 to 10
µg/L of silver. The range may be extended by dilution of the
5.1 Reagent grade chemicals shall be used in all tests.
original sample.
Unless otherwise indicated, it is intended that all reagents shall
7.3 This test method has been used successfully with
conform to the specifications of the Committee on Analytical
reagent water, natural surface water, and drinking water. The
Reagents of the American Chemical Society, when such
information on precision and bias may not apply to other
specifications are available. Other grades may be used, pro-
waters. It is the user’s responsibility to ensure the validity of
vided it is first ascertained that the reagent is of sufficiently
this test method for waters of untested matrices.
high purity to permit its use without lessening the accuracy of
the determination.
8. Summary of Test Method
5.2 Purity of Water—Unless otherwise indicated, references
8.1 Silver is determined by atomic absorption spectrometry.
to water shall be understood to mean reagent water conforming
The element, either dissolved or total recoverable, is chelated
to Specification D1193, Type I, II, or III water. Type I is
with ammonium pyrrolidine dithiocarbamate (APDC) and
preferred and more commonly used. Other reagent water types
extracted with methyl isobutyl ketone (MIBK). The extract is
may be used provided it is first ascertained that the water is of
aspirated into an air-acetylene flame of the spectrophotometer.
sufficiently high purity to permit its use without adversely
Total recoverable silver is determined following nitric acid
affecting the precision and bias of the test method. Type II
digestion and filtration.
water was specified at the time of round robin testing of these
test methods.
9. Interferences
NOTE 1—The user must ensure the type of reagent water chosen is
9.1 Concentrations of iron greater than 25 mg/Linterfere by
sufficientlyfreeofinterferences.Thewatershouldbeanalyzedusingthese
suppressing the silver absorption.
test methods.
10. Apparatus
6. Sampling
10.1 Atomic Absorption Spectrophotometer for use at 328.1
6.1 Collect the sample in accordance with Practices D3370.
nm. A general guide for the use of flame atomic absorption
The holding time for the samples may be calculated in
applications is given in Practice D4691.
accordance with Practice D4841.
NOTE 3—The manufacturer’s instructions should be followed for
6.2 Preserve samples for Test Method A with HNO (sp gr
3 instrumental parameters. Wave-lengths other than 328.1 nm may be used
1.42) to a pH of 2 or less immediately at the time of collection; if they have been determined to be equally suitable.
normally about 2 mL/L is required. If only dissolved silver is
10.2 Silver Hollow-Cathode Lamp.
to be determined, filter (11.13) the sample at time of collection
10.3 Pressure-Reducing Valves—The supplies of fuel and
through a 0.45-µm membrane filter before acidification.
oxidant shall be maintained at pressures somewhat higher than
NOTE 2—Alternatively, the pH may be adjusted in the laboratory within the controlled operating pressure of the instrument by suitable
14 days of collection. This could reduce hazards of working with acids in
pressure-reducing valves.
the field when appropriate.
11. Reagents and Materials
6.3 Do not preserve samples for Test Methods B and C at
the time of collection. If only dissolved silver is to be
11.1 Ammonium Pyrrolidine Dithiocarbamate (APDC) So-
determined, filter the sample through a 0.45-µm membrane
lution(1 g/100 mL)—Dissolve 1.0 g of APDC in 100 mL of
filter at time of collection.Add cyanogen iodide (CNI) solution
water. Prepare fresh before each use.
to the samples in the laboratory prior to analysis. For total
11.2 Bromophenol Blue Indicator Solution (0.1 g/100
recoverable silver it is preferable to add the cyanogen iodide to
mL)—Dissolve 0.1 g of bromophenol blue in 100 mL of 50 %
the entire sample to avoid a nonhomogeneous solution;
ethanol or isopropanol.
therefore, it is advisable to collect a discrete sample for silver.
11.3 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
chloric acid (HCl).
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
listed by the American Chemical Society, see Annual Standards for Laboratory Similar to that in Brown, E., Skougstad, M. W., and Fishman, M. J., “Methods
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia for Collection and Analysis of Water Samples for Dissolved Minerals and Gases,”
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book
MD. 5, Chapter A1, 1970, p. 46.
D3866 − 18
TABLE 1 Determination of Bias and Precision for Test Method A
11.4 Hydrochloric Acid (1 + 49)—Add 1 volume of hydro-
chloric acid (HCl, sp gr 1.19) to 49 volumes of water. Statistically
Amount Amount
Significant, Overall
Added, Found, Bias, Degrees of
11.5 Methyl Isobutyl Ketone (MIBK). (Warning—Avoid
95 % Precision,
µg/L µg/L % Freedom
Confidence S
inhalation and conduct all manipulation in a well-ventilated t
Ag Ag
Level
hood.)
Reagent Water, Type II
2.0 2.18 + 9.0 no 0.77 7
11.6 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
5.0 5.15 + 3.0 no 1.34 7
(HNO ).
8.0 8.08 + 1.0 no 1.86 7
Natural Water of Choice
NOTE 4—If a high reagent blank is obtained, distill the HNO or use a
2.0 2.37 + 18.5 yes 0.74 7
spectrograde acid.
5.0 4.99 −0.2 no 0.92 7
8.0 8.38 + 4.8 no 2.21 7
11.7 Silver Solution, Stock (1.0 mL = 100 µg Ag)—Crush
approximately2gof silver nitrate (AgNO ) crystals and dry to
constant mass at 40°C. Dissolve 0.1575 g of AgNO in water
12.3 To determine total recoverable silver, use 125-mL
containing 5 mLof concentrated HNO and dilute to 1000 mL.
beakers or flasks, add 5.0 mL of HNO (sp gr 1.42), and
Store in an amber glass bottle. A purchased silver stock
proceed as directed in 13.3 through 13.10. To determine
solution of appropriate known purity is also acceptable.
dissolved silver use 200-mL volumetric flasks and proceed as
11.8 Silver Solution, Intermediate (1.0 mL = 1.00 µg Ag)—
directed in 13.5 through 13.10. Treat the blank and each
Dilute 10.0 mL of silver stock solution and 5 mL of concen-
standard in the same manner as the samples.
trated HNO to 1000 mL with water. Store in an amber glass
12.4 Read directly in concentration if this capability is
bottle. A purchased stock solution of adequate purity is also
provided with the instrument or measure the absorbance of the
acceptable.
standards or construct an analytical curve by plotting the
11.9 Silver Solution, Standard (1.0 mL = 0.100 µg Ag)—
absorbances of standards versus micrograms of silver.
Dilute 100 mL of silver intermediate solution and 5 mL of
concentrated HNO to 1000 mL with water. Prepare fresh
13. Procedure
before use.
13.1 Measure a volume of a well-mixed acidified sample
11.10 Sodium Hydroxide Solution (100 g/L)—Dissolve 100
containing less than 1.0 µg of silver (100-mL maximum) into
g of NaOH in water and dilute to 1000 mL. a125-mLbeakerorflaskandadjustthevolumeto100mLwith
water.
11.11 Oxidant:
11.11.1 Air, that has been passed through a suitable filter to NOTE 5—If only dissolved silver is to be determined, measure a volume
of filtered and acidified sample containing less than 1.0 µg of silver (100
remove oil, water, and other foreign substances is the usual
mL maximum) into a 200-mL volumetric flask and adjust the volume to
oxidant.
100 mL and start with 13.5.
11.12 Fuel:
13.2 Add 5 mLof HNO (sp gr 1.42) (11.6) to each sample.
11.12.1 Acetylene-Standard, commercially available acety-
13.3 Heat the samples (between 65°C and 95°C) on a steam
lene is the usual fuel. Acetone, always present in acetylene
bath or hot plate below boiling in a well-ventilated hood until
cylinders, can affect analytical results. The cylinder should be
the volume has been reduced to 15 to 20 mL making certain
replaced at 345 kPa (50 psi). (Warning—“Purified” grade
that the samples do not boil.
acetylene containing a special proprietary solvent rather than
acetone must not be used with poly(vinyl chloride) tubing as
NOTE 6—For brines and samples with a high concentration of sus-
pended matter, the amount of reduction in volume is left to the discretion
weakening of the tubing walls causes a potentially hazardous
of the analyst.
situation.)
NOTE 7—Many laboratories have found block digestion systems a
useful way to digest samples for trace metals analysis. Systems typically
11.13 FilterPaper—Purchasesuitablefilterpaper.Typically
consist of either a metal or graphite block with wells to hold digestion
the filter papers have a pore size of 0.45-µm membrane.
tubes. The block temperature controller must be able to maintain unifor-
Material such as fine-textured, acid-washed, ashless paper, or
mity of temperature across all positions of the block. The digestion block
glass fiber paper are acceptable. The user must first ascertain
must be capable of maintaining a temperature between 65°C and 95°C.
that the filter paper is of sufficient purity to use without
For trace metals analysis, the digestion tubes should be constructed of
polypropylene and have a volume accuracy of at least 0.5 %. All lots of
adversely affecting the bias and precision of the test method.
tubes should come with a certificate of analysis to demonstrate suitability
for their intended purpose. If a block digestion system is used, reduced
12. Standardization
volumes of samples and reagents will be required. Make sure that the
reagent volumes maintain the same proportions as in the macro method.
12.1 An effective way to clean all glassware to be used for
preparation of standard solutions or in the digestion step, or
13.4 Cool and filter each sample through a filter (such as a
both, is by soaking the glassware for 2 h first with HNO fine-textured acid washed, ashless paper; 11.13) into a 200-mL
(1 + 1) and then rinsing with reagent water.
volumetric flask. Wash the filter paper two or three times with
water and adjust the filtrate to about 100 mL.
12.2 Prepare a blank and sufficient standards containing
from 0.0 to 1.0 µg of silver by diluting 0.0 to 10.0-mLportions 13.5 Add 2 drops of bromophenol blue indicator solution
of silver standard solution to approximately 100 mL. (11.2) and mix.
D3866 − 18
13.6 Adjust the pH by addition of NaOH solution (100 g/L) 15.4 Precision and bias for this test method conforms to
(11.10) until a blue color persists. Add HCl (1 + 49) (11.4)by Practice D2777 – 77, which was in place at the time of
drops until the blue color just disappears; then add 2.5 mL of collaborative testing. Under the allowances made in 1.4 of
HCl (1 + 49) (11.4) in excess. The pH at this point should be Practice D2777 – 13, these precision and bias data do meet
2.3. existing requirements for interlaboratory studies of Committee
D19 test methods.
NOTE 8—The pH adjustment in 13.6 may be made with a pH meter
instead of using indicator.
TEST METHOD B—ATOMIC ABSORPTION—
13.7 Add 2.5 mLofAPDC solution (11.1) and mix. The pH
DIRECT
should be approximately 2.8.
16. Scope
13.8 Add 10.0 mLof MIBK (11.5) and shake vigorously for
1 min. (Warning—Perform in a well ventilated hood (see
16.1 This test method covers the determination of dissolved
11.5).)
and total recoverable silver in most waters, and wastewaters.
13.9 Allow the layers to separate and add, carefully down
16.2 This test method is applicable in the range from 0.1 to
the side of the flask, water until the ketone layer is completely
10 mg/L of silver. The range may be extended by dilution of
in the neck of the flask.
the original sample.
NOTE 9—MIBK is soluble to some extent in water; therefore avoid any
16.3 This test method has been used successfully with
undue agitation of the solution during and after addition of water which
reagent water, natural surface water and ground waters, an
could result in a concentration of the metal chelate in the MIBK layer. To
industrialoutfall,andabrine.Theinformationonprecisionand
avoid this problem, MIBK-saturated water may be used to raise the MIBK
bias may not apply to other waters. It is the user’s responsi-
layer into the neck of the flask.
bility to ensure the validity of this test method for waters of
13.10 Atomize the ketone layer and record the scale reading
untested matrices.
or concentration (Note 10). Aspirate water-saturated MIBK
between each sample.
17. Summary of Test Method
NOTE 10—It is necessary to reduce the acetylene flow when aspirating
17.1 Silver is determined by atomic absorption spectrom-
an organic solvent (MIBK) to obtain a nonluminous flame.Also allow the
etry. Dissolved silver is determined after filtration (11.13) and
flame conditions to come to equilibrium before aspirating samples.
addition of cyanogen iodide. Total recoverable silver is deter-
14. Calculation minedbyaspiratingthesamplefollowingadditionofcyanogen
iodide to solubilize the silver and, if necessary, the sample is
14.1 Ifinstrumentreadoutisnotinconcentration,determine
filtered prior to aspiration.
the weight of silver in each sample by referring to 12.4.
Calculate the concentration of silver in micrograms per litre as
18. Interferences
follows:
18.1 Background correction by techniques such as a con-
Silver, µg/L 5 ~1000/A! 3B (1)
tinuous source, nonabsorbing lines, or chelation-extraction
where:
(Test Method A) may be necessary to determine low levels of
1000 = 1000 mL/L, silver in some waters.
A = volume of original sample, mL, and
B = weight of silver in sample, µg. 19. Apparatus
19.1 See Section 10.
15. Precision and Bias
15.1 The single-operator and overall precision of this test
20. Reagents and Materials
method within its designated range for four laboratories, which
20.1 Ammonium Hydroxide (sp gr 0.90)—Concentrated am-
include a total of seven operators analyzing each sample on
monium hydroxide (NH OH).
three different days varies with the quantity being tested, see
20.2 Cyanogen Iodide Solution—Dissolve 65 g of potas-
Table 1.
sium cyanide (KCN) in 50 mL of iodine solution (see 20.3).
15.2 Recoveries of known amounts of silver (from silver
Dissolve2gof sodium hydroxide in the solution, add 40 mL
nitrate) in a series of prepared standards for the same labora-
of concentrated ammonium hydroxide, and dilute to 1 L with
tories and operators are shown in Table 1.
water. The solution is stable for 1 week.
15.3 The collaborative test data were obtained on reagent
NOTE 11—Before discarding the unused solution, add 50 mL of 3 %
water, natural surface water, and drinkin
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D3866 − 12 D3866 − 18
Standard Test Methods for
Silver in Water
This standard is issued under the fixed designation D3866; 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.
1. Scope*
1.1 These test methods cover the atomic absorption determination of silver in water. Section 34 on Quality Control pertains to
these test methods. Three test methods are given as follows:
Concentration
Range Sections
Test Method A—Atomic Absorp- 1 to 10 μg/L 7 to 15
A
tion—Chelation-Extraction
Test Method A—Atomic Absorption—Chelation-Extraction 1 to 10 μg/L 7 – 15
A
Test Method B—Atomic Absorp- 0.1 to 10 mg/L 16 to 24
tion—Direct
Test Method B—Atomic Absorption—Direct 0.1 to 10 mg/L 16 – 24
Test Method C—Atomic Absorp- 1 to 25 μg/L 25 to 33
tion—Graphite Furnace
Test Method C—Atomic Absorption—Graphite 1 to 25 μg/L 25 – 33
Furnace
A
Similar to that in Brown, E., Skougstad, M. W., and Fishman, M. J., “Methods for Collection and Analysis of Water Samples for Dissolved Minerals and Gases,” Techniques
of Water-Resources Investigations of the U.S. Geological Survey, Book 5, Chapter A1, 1970, p. 46.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values statedgiven
in each system are mathematical conversions and may not be exact equivalents; therefore, each system shall be used independently
of the other.parentheses are mathematical conversion to inch-pound units that are provided for information only and are not
considered standard.
1.3 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. Specific precautionary statements are given in Note 411.5, Note 611.12.1, Note
1113.8, and Note 1522.1.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
D1976 Test Method for Elements in Water by Inductively-Coupled Argon Plasma Atomic Emission Spectroscopy
D2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
D3370 Practices for Sampling Water from Closed Conduits
D3919 Practice for Measuring Trace Elements in Water by Graphite Furnace Atomic Absorption Spectrophotometry
D4691 Practice for Measuring Elements in Water by Flame Atomic Absorption Spectrophotometry
These test methods are under the jurisdiction of ASTM Committee D19 on Water and are the direct responsibility of Subcommittee D19.05 on Inorganic Constituents
in Water.
Current edition approved Sept. 1, 2012Feb. 1, 2018. Published September 2012March 2018. Originally approved in 1979. Last previous edition approved in 20072012
as D3866 – 07.D3866 – 12. DOI: 10.1520/D3866–12.10.1520/D3866-18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3866 − 18
D4841 Practice for Estimation of Holding Time for Water Samples Containing Organic and Inorganic Constituents
D5673 Test Method for Elements in Water by Inductively Coupled Plasma—Mass Spectrometry
D5810 Guide for Spiking into Aqueous Samples
D5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis
3. Terminology
3.1 Definition of Term Specific to These Test Methods:
3.1.1 laboratory control sample, n—a solution with a certified concentration of silver.
3.1.2 total recoverable silver, n—an arbitrary analytical term relating to forms of silver that are determinable by the digestion
method that is included in the procedures.
3.1 Definitions—Definitions: For definition of terms used in these test methods, refer to Terminology D1129.
3.1.1 For definitions of terms used in this standard, refer to Terminology D1129.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 laboratory control sample, n—a solution with a certified concentration of silver.
3.2.2 total recoverable silver, n—a descriptive term relating to forms of silver that are determinable by the digestion method that
is included in these test methods.
4. Significance and Use
4.1 The principal adverse effect of silver in the body is cosmetic. It causes argyria, a permanent, blue-gray discoloration of the
skin, eyes, and mucous membranes.
4.2 Relatively small quantities of silver are bactericidal or bacteriostatic and find limited use in both disinfection of swimming
pool waters and point-of-use water filters.
4.3 ICP-MS or ICP-AES may also be appropriate but at a higher instrument cost. See Test Methods D5673 and D1976.
5. Purity of Reagents
5.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform
to the specifications of the Committee on Analytical Reagents of the American Chemical Society, when such specifications are
available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use
without lessening the accuracy of the determination.
5.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to
Specification D1193, Type I, II, or III water. Type I is preferred and more commonly used. Other reagent water types may be used
provided it is first ascertained that the water is of sufficiently high purity to permit its use without adversely affecting the precision
and bias of the test method. Type II water was specified at the time of round robin testing of these test methods.
NOTE 1—The user must ensure the type of reagent water chosen is sufficiently free of interferences. The water should be analyzed using thethese test
method.methods.
6. Sampling
6.1 Collect the sample in accordance with Practices D3370. The holding time for the samples may be calculated in accordance
with Practice D4841.
6.2 Preserve samples for Test Method A with HNO (sp gr 1.42) to a pH of 2 or less immediately at the time of collection;
normally about 2 mL/L is required. If only dissolved silver is to be determined, filter (11.13) the sample at time of collection
through a 0.45-μm membrane filter before acidification.
NOTE 2—Alternatively, the pH may be adjusted in the laboratory if the sample is returned within 14 days. within 14 days of collection. This could
reduce hazards of working with acids in the field when appropriate.
6.3 Do not preserve samples for Test Methods B and C at the time of collection. If only dissolved silver is to be determined,
filter the sample through a 0.45-μm membrane filter at time of collection. Add cyanogen iodide (CNI) solution to the samples in
the laboratory prior to analysis. For total recoverable silver it is preferable to add the cyanogen iodide to the entire sample to avoid
a nonhomogeneous solution; therefore, it is advisable to collect a discrete sample for silver.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed by
the American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
D3866 − 18
TEST METHOD A—ATOMIC ABSORPTION—CHELATION EXTRACTION
7. Scope
7.1 This test method covers the determination of dissolved and total recoverable silver in most water and wastewaters.
7.2 This test method is applicable in the range from 1 to 10 μg/L of silver. The range may be extended by dilution of the original
sample.
7.3 This test method has been used successfully with reagent water, natural surface water, and drinking water. The information
on precision and bias may not apply to other waters. It is the user’s responsibility to ensure the validity of this test method for
waters of untested matrices.
7. Scope
7.1 This test method covers the determination of dissolved and total recoverable silver in most water and wastewaters.
7.2 This test method is applicable in the range from 1 to 10 μg/L of silver. The range may be extended by dilution of the original
sample.
7.3 This test method has been used successfully with reagent water, natural surface water, and drinking water. The information
on precision and bias may not apply to other waters. It is the user’s responsibility to ensure the validity of this test method for
waters of untested matrices.
8. Summary of Test Method
8.1 Silver is determined by atomic absorption spectrometry. The element, either dissolved or total recoverable, is chelated with
ammonium pyrrolidine dithiocarbamate (APDC) and extracted with methyl isobutyl ketone (MIBK). The extract is aspirated into
an air-acetylene flame of the spectrophotometer. Total recoverable silver is determined following nitric acid digestion and filtration.
9. Interferences
9.1 Concentrations of iron greater than 25 mg/L interfere by suppressing the silver absorption.
10. Apparatus
10.1 Atomic Absorption Spectrophotometer for use at 328.1 nm. A general guide for the use of flame atomic absorption
applications is given in Practice D4691.
NOTE 3—The manufacturer’s instructions should be followed for instrumental parameters. Wave-lengths other than 328.1 nm may be used if they have
been determined to be equally suitable.
10.2 Silver Hollow-Cathode Lamp.
10.3 Pressure-Reducing Valves—The supplies of fuel and oxidant shall be maintained at pressures somewhat higher than the
controlled operating pressure of the instrument by suitable pressure-reducing valves.
11. Reagents and Materials
11.1 Ammonium Pyrrolidine Dithiocarbamate (APDC) Solution(1 g/100 mL)—Dissolve 1.0 g of APDC in 100 mL of water.
Prepare fresh before each use.
11.2 Bromophenol Blue Indicator Solution (0.1 g/100 mL)—Dissolve 0.1 g of bromophenol blue in 100 mL of 50 % ethanol
or isopropanol.
11.3 Hydrochloric Acid (sp gr 1.19)—Concentrated hydrochloric acid (HCl).
11.4 Hydrochloric Acid (1 + 49)—Add 1 volume of hydrochloric acid (HCl, sp gr 1.19) to 49 volumes of water.
11.5 Methyl Isobutyl Ketone (MIBK).
NOTE 4—Warning: Avoid inhalation and conduct all manipulation in a well-ventilated hood.(Warning—Avoid inhalation and conduct all
manipulation in a well-ventilated hood.)
11.6 Nitric Acid (sp gr 1.42)—Concentrated nitric acid (HNO ).
NOTE 4—If a high reagent blank is obtained, distill the HNO or use a spectrograde acid.
11.7 Silver Solution, Stock (1.0 mL = 100 μg Ag)—Crush approximately 2 g of silver nitrate (AgNO ) crystals and dry to
constant mass at 40°C. Dissolve 0.1575 g of AgNO in water containing 5 mL of concentrated HNO and dilute to 1000 mL. Store
3 3
in an amber glass bottle. A purchased silver stock solution of appropriate known purity is also acceptable.
Similar to that in Brown, E., Skougstad, M. W., and Fishman, M. J., “Methods for Collection and Analysis of Water Samples for Dissolved Minerals and Gases,”
Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book 5, Chapter A1, 1970, p. 46.
D3866 − 18
11.8 Silver Solution, Intermediate (1.0 mL = 1.00 μg Ag)—Dilute 10.0 mL of silver stock solution and 5 mL of concentrated
HNO to 1000 mL with water. Store in an amber glass bottle. A purchased stock solution of adequate purity is also acceptable.
11.9 Silver Solution, Standard (1.0 mL = 0.100 μg Ag)—Dilute 100 mL of silver intermediate solution and 5 mL of concentrated
HNO to 1000 mL with water. Prepare fresh before use.
11.10 Sodium Hydroxide Solution (100 g/L)—Dissolve 100 g of NaOH in water and dilute to 1000 mL.
11.11 Oxidant:
11.11.1 Air, that has been passed through a suitable filter to remove oil, water, and other foreign substances is the usual oxidant.
11.12 Fuel:
11.12.1 Acetylene-Standard, commercially available acetylene is the usual fuel. Acetone, always present in acetylene cylinders,
can affect analytical results. The cylinder should be replaced at 345 kPa (50 psi). (Warning—“Purified” grade acetylene containing
a special proprietary solvent rather than acetone must not be used with poly(vinyl chloride) tubing as weakening of the tubing walls
causes a potentially hazardous situation.Warning—)see Note 6.)
NOTE 6—Warning: “Purified” grade acetylene containing a special proprietary solvent rather than acetone must not be used with poly(vinyl chloride)
tubing as weakening of the tubing walls causes a potentially hazardous situation.
11.13 Filter Paper—Purchase suitable filter paper. Typically the filter papers have a pore size of 0.45-μm membrane. Material
such as fine-textured, acid-washed, ashless paper, or glass fiber paper are acceptable. The user must first ascertain that the filter
paper is of sufficient purity to use without adversely affecting the bias and precision of the test method.
12. Standardization
12.1 An effective way to clean all glassware to be used for preparation of standard solutions or in the digestion step, or both,
is by soaking the glassware for 2 h first with HNO (1 + 1) and then rinsing with reagent water.
12.2 Prepare a blank and sufficient standards containing from 0.0 to 1.0 μg of silver by diluting 0.0 to 10.0-mL portions of silver
standard solution to approximately 100 mL.
12.3 To determine total recoverable silver, use 125-mL beakers or flasks, add 5.0 mL of HNO (sp gr 1.42), and proceed as
directed in 13.3 through 13.10. To determine dissolved silver use 200-mL volumetric flasks and proceed as directed in 13.5 through
13.10. Treat the blank and each standard in the same manner as the samples.
12.4 Construct Read directly in concentration if this capability is provided with the instrument or measure the absorbance of
the standards or construct an analytical curve by plotting the absorbances of standards versus micrograms of silver. Alternatively,
read directly in concentration if this capability is provided with the instrument.
13. Procedure
13.1 Measure a volume of a well-mixed acidified sample containing less than 1.0 μg of silver (100-mL maximum) into a
125-mL beaker or flask and adjust the volume to 100 mL with water.
NOTE 5—If only dissolved silver is to be determined, measure a volume of filtered and acidified sample containing less than 1.0 μg of silver (100 mL
maximum) into a 200-mL volumetric flask and adjust the volume to 100 mL and start with 13.5.
13.2 Add 5 mL of HNO (sp gr 1.42) (11.6)(11.6) to each sample.
13.3 Heat the samples (between 65°C and 95°C) on a steam bath or hot plate below boiling in a well-ventilated hood until the
volume has been reduced to 15 to 20 mL making certain that the samples do not boil.
NOTE 6—For brines and samples with a high concentration of suspended matter, the amount of reduction in volume is left to the discretion of the
analyst.
NOTE 7—Many laboratories have found block digestion systems a useful way to digest samples for trace metals analysis. Systems typically consist of
TABLE 1 Determination of Bias and Precision for Test Method A
Statistically
Amount Amount
Significant, Overall
Added, Found, Bias, Degrees of
95 % Precision,
μg/L μg/L % Freedom
Confidence S
t
Ag Ag
Level
Reagent Water, Type II
2.0 2.18 + 9.0 no 0.77 7
5.0 5.15 + 3.0 no 1.34 7
8.0 8.08 + 1.0 no 1.86 7
Natural Water of Choice
2.0 2.37 + 18.5 yes 0.74 7
5.0 4.99 −0.2 no 0.92 7
8.0 8.38 + 4.8 no 2.21 7
D3866 − 18
either a metal or graphite block with wells to hold digestion tubes. The block temperature controller must be able to maintain uniformity of temperature
across all positions of the block. The digestion block must be capable of maintaining a temperature between 65°C and 95°C. For trace metals analysis,
the digestion tubes should be constructed of polypropylene and have a volume accuracy of at least 0.5 %. All lots of tubes should come with a certificate
of analysis to demonstrate suitability for their intended purpose. If a block digestion system is used, reduced volumes of samples and reagents will be
required. Make sure that the reagent volumes maintain the same proportions as in the macro method.
13.4 Cool and filter each sample through a filter (such as a fine-textured acid washed, ashless paper)paper; 11.13) into a 200-mL
volumetric flask. Wash the filter paper two or three times with water and adjust the filtrate to about 100 mL.
13.5 Add 2 drops of bromophenol blue indicator solution (11.2)(11.2) and mix.
13.6 Adjust the pH by addition of NaOH solution (100 g/L) (11.10)(11.10) until a blue color persists. Add HCl (1 + 49)
(11.4)(11.4) by drops until the blue color just disappears; then add 2.5 mL of HCl (1 + 49) (11.4)(11.4) in excess. The pH at this
point should be 2.3.
NOTE 8—The pH adjustment in 13.6 may be made with a pH meter instead of using indicator.
13.7 Add 2.5 mL of APDC solution (11.1)(11.1) and mix. The pH should be approximately 2.8.
13.8 Add 10.0 mL of MIBK (11.5)(11.5) and shake vigorously for 1 min. (Warning—Perform in a well ventilated hood (see
11.5).)
NOTE 11—Warning: Perform in a well ventilated hood (see Note 4).
13.9 Allow the layers to separate and add, carefully down the side of the flask, water until the ketone layer is completely in the
neck of the flask.
NOTE 9—MIBK is soluble to some extent in water; therefore avoid any undue agitation of the solution during and after addition of water which could
result in a concentration of the metal chelate in the MIBK layer. To avoid this problem, MIBK-saturated water may be used to raise the MIBK layer into
the neck of the flask.
13.10 Atomize the ketone layer and record the scale reading or concentration (Note 1310). Aspirate water-saturated MIBK
between each sample.
NOTE 10—It is necessary to reduce the acetylene flow when aspirating an organic solvent (MIBK) to obtain a nonluminous flame. Also allow the flame
conditions to come to equilibrium before aspirating samples.
14. Calculation
14.1 Determine If instrument readout is not in concentration, determine the weight of silver in each sample by referring to
12.312.4. Calculate the concentration of silver in micrograms per litre as follows:
Silver, µg/L5 1000/A 3B (1)
~ !
where:
1000 = 1000 mL / Liter
1000 = 1000 mL/L,
A = volume of original sample, mL, and
B = weight of silver in sample, μg.
15. Precision and Bias
15.1 The single-operator and overall precision of this test method within its designated range for four laboratories, which
include a total of seven operators analyzing each sample on three different days varies with the quantity being tested, see Table
1.
15.2 Recoveries of known amounts of silver (from silver nitrate) in a series of prepared standards for the same laboratories and
operators are shown in Table 1.
15.3 The collaborative test data were obtained on reagent water, natural surface water, and drinking water. This data may not
apply to untested matrices. It is the user’s responsibility to ensure the validity of this test method for waters of untested matrices.
15.4 Precision and bias for this test method conforms to Practice D2777 – 77, which was in place at the time of collaborative
testing. Under the allowances made in 1.4 of Practice D2777 – 08,13, these precision and bias data do meet existing requirements
for interlaboratory studies of Committee D19 test methods.
TEST METHOD B—ATOMIC ABSORPTION—DIRECT
16. Scope
16.1 This test method covers the determination of dissolved and total recoverable silver in most waters, and wastewaters.
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D19-1062. Contact ASTM Customer
Service at [e-mail].
D3866 − 18
16.2 This test method is applicable in the range from 0.1 to 10 mg/L of silver. The range may be extended by dilution of the
original sample.
16.3 This test method has been used successfully with reagent water, natural surface water and ground waters, an industrial
outfall, and a brine. The information on precision and bias may not apply to other waters. It is the user’s responsibility to ensure
the validity of this test method for waters of untested matrices.
16. Scope
16.1 This test method covers the determination of dissolved and total recoverable silver in most waters, and wastewaters.
16.2 This test method is applicable in the range from 0.1 to 10 mg/L of silver. The range may be extended by dilution of the
original sample.
16.3 This test method has been used successfully with reagent water, natural surface water and ground waters, an industrial
outfall, and a brine. The information on precision and bias may not apply to other waters. It is the user’s responsibility to ensure
the validity of this test method for waters of untested matrices.
17. Summary of Test Method
17.1 Silver is determined by atomic absorption spectrometry. Dissolved silver is determined after filtration (11.13) and addition
of cyanogen iodide. Total recoverable silver is determined by aspirating the sample following addition of cyanogen iodide to
solubilize the silver and, if necessary, the sample is filtered prior to aspiration.
18. Interferences
18.1 Background correction by techniques such as a continuous source, nonabsorbing lines, or chelation-extraction (Test
Method A) may be necessary to determine low levels of silver in some waters.
19. Apparatus
19.1 See Section 10.
20. Reagents and Materials
20.1 Ammonium Hydroxide (sp gr 0.90)—Concentrated ammonium hydroxide (NH OH).
20.2 Cyanogen Iodide Solution—Dissolve 65 g of potassium cyanide (KCN) in 50 mL of iodine solution (see 20.3). Dissolve
2 g of
...