ASTM D1688-17

Standard Test Methods for Copper in Water

SIGNIFICANCE AND USE
4.1 Copper is found in naturally occurring minerals principally as a sulfide, oxide, or carbonate. It makes up approximately 0.01 % of the earth's crust and is obtained commercially from such ores as chalcopyrite (CuFeS2). Copper is also found in biological complexes such as hemocyanin.  
4.2 Copper enters water supplies through the natural process of dissolution of minerals, through industrial effluents, through its use, as copper sulfate, to control biological growth in some reservoirs and distribution systems, and through corrosion of copper alloy water pipes. Industries whose wastewaters may contain significant concentrations of copper include mining, ammunition production, and most metal plating and finishing operations. It may occur in simple ionic form or in one of many complexes with such groups as cyanide, chloride, ammonia, or organic ligands.  
4.3 Although its salts, particularly copper sulfate, inhibit biological growth such as some algae and bacteria, copper is considered essential to human nutrition and is not considered a toxic chemical at concentrations normally found in water supplies.  
4.4 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 determination of copper in water by atomic absorption spectrophotometry. Section 34 on Quality Control pertains to these test methods. Three test methods are included as follows:    
Test Method  
Concentration
Range  
Sections  
A—Atomic Absorption,
Direct  
0.05 to 5 mg/L  
7 – 15  
B—Atomic Absorption,
Chelation-Extraction  
50 to 500 μg/L  
16 – 24  
C—Atomic Absorption,
Graphite Furnace  
5 to 100 μg/L  
25 – 33  
1.2 Either dissolved or total recoverable copper may be determined. Determination of dissolved copper requires filtration through a 0.45-μm (11.10) membrane filter at the time of collection. In-line membrane filtration is preferable.  
1.3 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.  
1.4 Three former photometric test methods were discontinued. Refer to Appendix X1 for historical information.  
1.5 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. For specific hazard statements, see 11.3, 11.9.1, 20.10, and 22.11.  
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-May-2017
• 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 D3558-15(2023) - Standard Test Methods for Cobalt in Water
• Effective Date: 01-Dec-2023
• 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 D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM D1066-18e1 - Standard Practice for Sampling Steam
• Effective Date: 01-Aug-2018
• Refers: ASTM D1066-18 - Standard Practice for Sampling Steam
• Effective Date: 01-Aug-2018
• 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 D1687-17 - Standard Test Methods for Chromium in Water
• Effective Date: 01-Jun-2017
• Refers: ASTM D3557-17 - Standard Test Methods for Cadmium in Water
• Effective Date: 01-Jun-2017
• Refers: ASTM D1691-17 - Standard Test Methods for Zinc in Water
• Effective Date: 01-Jun-2017
• Refers: ASTM D5673-15 - Standard Test Method for Elements in Water by Inductively Coupled Plasma—Mass Spectrometry
• Effective Date: 01-Jul-2015
• Refers: ASTM D3559-15 - Standard Test Methods for Lead in Water (Withdrawn 2024)
• Effective Date: 01-Jun-2015
• Refers: ASTM D3558-15 - Standard Test Methods for Cobalt in Water
• Effective Date: 01-Feb-2015
• 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 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 D1691-12 - Standard Test Methods for Zinc in Water
• Effective Date: 01-Sep-2012

Overview

ASTM D1688-17: Standard Test Methods for Copper in Water provides internationally recognized procedures for determining copper concentrations in various water samples using atomic absorption spectrophotometry (AAS). This standard, developed by ASTM Committee D19 on Water, defines three robust methods to measure both dissolved and total recoverable copper in water sources such as natural bodies, drinking water, industrial effluents, wastewater, and brines. Accurate detection and quantification of copper in water is essential for water quality monitoring, regulatory compliance, environmental assessment, and industrial process control.

Key Topics

• Test Methods Covered
  ASTM D1688-17 includes three AAS-based methods:

  • Method A: Direct Atomic Absorption
    • Measures 0.05 to 5 mg/L copper concentration.
    • Suitable for routine analysis in most water and wastewater samples.
  • Method B: Chelation-Extraction Atomic Absorption
    • Detects copper from 50 to 500 μg/L.
    • Employs a chelation-extraction step to enhance sensitivity.
    • Useful for samples with interfering substances or lower concentration ranges.
  • Method C: Graphite Furnace Atomic Absorption
    • Detects copper from 5 to 100 μg/L.
    • Utilizes a graphite furnace for increased sensitivity.
    • Ideal for trace-level analyses in varied matrices.

• Sample Types

  • Either total recoverable or dissolved copper can be measured.
  • Dissolved copper determination requires filtration through a 0.45-μm membrane at the time of sample collection.

• Water Sources Analyzed

  • Natural waters (rivers, lakes, groundwater)
  • Drinking water
  • Industrial wastewater and effluents
  • Brines and artificial seawater

• Significance

  • Copper is prevalent in the environment and industry, entering water supplies from natural mineral dissolution, industrial processes, piping corrosion, and use in biocidal formulations.
  • Essential in trace amounts for nutrition, but requires monitoring to prevent excessive accumulation and to comply with water quality limits.
  • The methods outlined provide validated, precise, and accurate quantification vital for environmental monitoring and public health protection.

Applications

• Regulatory Compliance

  • Supports municipal water utilities in meeting national and international standards for copper content in potable water.
  • Assists industries such as mining, metal plating, and manufacturing in demonstrating compliance with wastewater discharge permits.

• Environmental Monitoring

  • Enables environmental agencies and researchers to assess copper contamination in aquatic ecosystems and track pollution sources.

• Industrial Quality Control

  • Facilitates monitoring of process water and effluents in a wide range of industries to maintain quality and minimize environmental impact.

• Public Health

  • Essential for supporting safety in drinking water distribution systems, particularly where copper piping is in use and corrosion may elevate copper concentrations.

• Research and Development

  • Applicable in R&D laboratories for method validation studies, environmental surveys, and technology development related to water treatment and pollution mitigation.

Related Standards

• ASTM D1068: Test Methods for Iron in Water
• ASTM D1691: Test Methods for Zinc in Water
• ASTM D1886: Test Methods for Nickel in Water
• ASTM D1976: Test Method for Elements in Water by ICP Emission Spectrometry
• ASTM D5673: Test Method for Elements in Water by ICP Mass Spectrometry
• ASTM D1129: Terminology Relating to Water
• ASTM D1193: Specification for Reagent Water

Utilizing ASTM D1688-17 helps ensure reliable, consistent, and recognized determinations of copper in water, supporting protection of human health, the environment, and compliance with water quality regulations. Regular use of this standard fosters international comparability of data in water analysis and monitoring.

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: D1688 − 17
Standard Test Methods for
Copper in Water
This standard is issued under the fixed designation D1688; 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* 2. Referenced Documents
2.1 ASTM Standards:
1.1 These test methods cover the determination of copper in
D858 Test Methods for Manganese in Water
water by atomic absorption spectrophotometry. Section 34 on
D1066 Practice for Sampling Steam
Quality Control pertains to these test methods. Three test
D1068 Test Methods for Iron in Water
methods are included as follows:
D1129 Terminology Relating to Water
Concentration
Test Method Sections
Range D1193 Specification for Reagent Water
A—Atomic Absorption, 0.05 to 5 mg/L 7–15
D1687 Test Methods for Chromium in Water
Direct
D1691 Test Methods for Zinc in Water
B—Atomic Absorption, 50 to 500 µg/L 16–24
Chelation-Extraction D1886 Test Methods for Nickel in Water
C—Atomic Absorption, 5 to 100 µg/L 25–33
D1976 Test Method for Elements in Water by Inductively-
Graphite Furnace
Coupled Argon Plasma Atomic Emission Spectroscopy
1.2 Either dissolved or total recoverable copper may be
D2777 Practice for Determination of Precision and Bias of
determined. Determination of dissolved copper requires filtra-
Applicable Test Methods of Committee D19 on Water
tion through a 0.45-µm (11.10) membrane filter at the time of
D3370 Practices for Sampling Water from Closed Conduits
collection. In-line membrane filtration is preferable.
D3557 Test Methods for Cadmium in Water
D3558 Test Methods for Cobalt in Water
1.3 The values stated in SI units are to be regarded as
D3559 Test Methods for Lead in Water
standard. The values given in parentheses are mathematical
D3919 Practice for Measuring Trace Elements in Water by
conversion to inch-pound units that are provided for informa-
Graphite Furnace Atomic Absorption Spectrophotometry
tion only and are not considered standard.
D4841 Practice for Estimation of Holding Time for Water
1.4 Three former photometric test methods were discontin-
Samples Containing Organic and Inorganic Constituents
ued. Refer to Appendix X1 for historical information.
D5673 Test Method for Elements in Water by Inductively
Coupled Plasma—Mass Spectrometry
1.5 This standard does not purport to address all of the
D5810 Guide for Spiking into Aqueous Samples
safety concerns, if any, associated with its use. It is the
D5847 Practice for Writing Quality Control Specifications
responsibility of the user of this standard to establish appro-
for Standard Test Methods for Water Analysis
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. For specific hazard
3. Terminology
statements, see 11.3, 11.9.1, 20.10, and 22.11.
1.6 This international standard was developed in accor-
3.1 Definitions:
dance with internationally recognized principles on standard-
3.1.1 For definitions of terms used in this standard, refer to
ization established in the Decision on Principles for the
Terminology D1129.
Development of International Standards, Guides and Recom-
3.2 Definitions of Terms Specific to This Standard:
mendations issued by the World Trade Organization Technical
3.2.1 continuing calibration blank, n—a solution containing
Barriers to Trade (TBT) Committee.
no analytes (of interest) which is used to verify blank response
and freedom from carryover.
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
CurrenteditionapprovedJune1,2017.PublishedJuly2017.Originallyapproved contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
in 1959. Last previous edition approved in 2012 as D1688 – 12. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D1688-17. 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
D1688 − 17
3.2.2 continuing calibration verification, n—a solution (or 6. Sampling
setofsolutions)ofknownconcentrationusedtoverifyfreedom
6.1 Collect the sample in accordance with Practices D1066
from excessive instrumental drift; the concentration is to cover
and D3370, as applicable.
the range of calibration curve.
6.2 Samplesshallbepreservedwithnitricacid(HNO ,spgr
3.2.3 total recoverable copper, n—a descriptive term relat-
1.42) to a pH of 2 or less immediately at the time of collection,
ing to the forms of copper recovered in the acid-digestion
normally about 2 mL/L. If only dissolved copper is to be
procedure specified in this test standard.
determined, the sample shall be filtered through a 0.45-µm
(11.10) membrane filter before acidification. The holding time
4. Significance and Use
for samples may be calculated in accordance with Practice
D4841.
4.1 Copper is found in naturally occurring minerals princi-
pally as a sulfide, oxide, or carbonate. It makes up approxi-
NOTE 1—Alternatively, the pH may be adjusted in the laboratory within
mately 0.01 % of the earth’s crust and is obtained commer- 14 days of collection. However, acid must be added at least 24 hours
before analysis to dissolve any metals that adsorb to the container walls.
cially from such ores as chalcopyrite (CuFeS ). Copper is also
This could reduce hazards of working with acids in the field when
found in biological complexes such as hemocyanin.
appropriate.
4.2 Copperenterswatersuppliesthroughthenaturalprocess
TEST METHOD A—ATOMIC
of dissolution of minerals, through industrial effluents, through
ABSORPTION, DIRECT
its use, as copper sulfate, to control biological growth in some
reservoirs and distribution systems, and through corrosion of
7. Scope
copper alloy water pipes. Industries whose wastewaters may
7.1 This test method covers the determination of dissolved
contain significant concentrations of copper include mining,
and total recoverable copper in most waters and waste waters.
ammunition production, and most metal plating and finishing
7.2 This test method is applicable in the range from 0.05 to
operations.Itmayoccurinsimpleionicformorinoneofmany
5 mg/L of copper. The range may be extended to concentra-
complexes with such groups as cyanide, chloride, ammonia, or
tions greater than 5 mg/L by dilution of the sample.
organic ligands.
7.3 Collaborative test data were obtained on reagent water,
4.3 Although its salts, particularly copper sulfate, inhibit
river water, tap water, ground water, lake water, refinery
biological growth such as some algae and bacteria, copper is
primary treated effluent, and two untreated waste waters. The
considered essential to human nutrition and is not considered a
information on precision and bias may not apply to other
toxic chemical at concentrations normally found in water
waters.
supplies.
8. Summary of Test Method
4.4 ICP-MS or ICP-AES may also be appropriate but at a
higher instrument cost. See Test Methods D5673 and D1976.
8.1 Copper is determined by atomic absorption spectropho-
tometry. Dissolved copper in the filtered sample is aspirated
5. Purity of Reagents
directly with no pretreatment. Total recoverable copper in the
sampleisaspiratedfollowinghydrochloric-nitricaciddigestion
5.1 Reagent grade chemicals shall be used in all tests.
and filtration. The same digestion procedure may be used to
Unless otherwise indicated, it is intended that all reagents shall
determine total recoverable cadmium (Test Methods D3557),
conform to the specifications of the Committee on Analytical
chromium (Test Methods D1687), cobalt (Test Methods
Reagents of the American Chemical Society, where such
D3558), iron (Test Methods D1068), lead (Test Methods
specifications are available. Other grades may be used, pro-
D3559), manganese (Test Methods D858), nickel (Test Meth-
vided it is first ascertained that the reagent is of sufficiently
ods D1886), and zinc (Test Methods D1691).
high purity to permit its use without lessening the accuracy of
the determination.
9. Interferences
9.1 Sodium, potassium, sulfate, and chloride (8000 mg/L
5.2 Purity of Water—Unless otherwise indicated, references
each),calciumandmagnesium(5000mg/Leach),nitrate(2000
towatershallbeunderstoodtomeanreagentwaterconforming
mg/L), iron (1000 mg/L), and cadmium, lead, nickel, zinc,
to Specification D1193, Type I. Other reagent water types may
cobalt, manganese, and chromium (10 mg/L each) do not
be used, provided it is first ascertained that the water is of
interfere.
sufficiently high purity to permit its use without lessening the
bias and precision of the determination. Type II water was
9.2 Background correction or a chelation-extraction proce-
specified at the time of round-robin testing of this test method.
dure (see Test Method B) may be necessary to determine low
levels of copper in some waters.
NOTE 2—Instrument manufacturers’ instructions for use of the specific
Reagent Chemicals, American Chemical Society Specifications, American
correction technique should be followed.
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
listed by the American Chemical Society, see Annual Standards for Laboratory 10. Apparatus
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
10.1 Atomic Absorption Spectrophotometer, for use at 324.7
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. nm.
D1688 − 17
NOTE 3—The manufacturer’s instructions should be followed for all
Material such as fine-textured, acid-washed, ashless paper, or
instrumental parameters. A wavelength other than 324.7 nm may be used
glass fiber paper are acceptable. The user must first ascertain
if it has been determined to be equally suitable.
that the filter paper is of sufficient purity to use without
10.1.1 Copper Hollow-Cathode Lamp—Multielement
adversely affecting the bias and precision of the test method.
hollow-cathode lamps are available and have been found
satisfactory.
12. Standardization
10.2 Pressure-Reducing Valves—The supplies of fuel and
12.1 Prepare 100 mL each of a blank and at least four
oxidant shall be maintained at pressures somewhat higher than
standardsolutionstobrackettheexpectedcopperconcentration
the controlled operating pressure of the instrument by suitable
range of the samples to be analyzed by diluting the standard
valves.
copper solution (11.2) with HNO (1 + 499 (11.5). Prepare the
standardseachtimethetestistobeperformedorasdetermined
11. Reagents and Materials
by Practice D4841.
11.1 Copper Solution, Stock (1.0 mL = 1.0 mg Cu)—
12.2 When determining total recoverable copper add 0.5
Dissolve 1.000 g of electrolytic copper contained in a 250-mL
mLof HNO (sp gr 1.42) (11.4)and proceed as directed in 13.3
beaker in a mixture of 15 mLof HNO (sp gr 1.42) and 15 mL
– 13.5.When determining dissolved copper proceed with 13.6.
ofwater.Slowlyadd4mLofH SO (1 + 1)andheatuntilSO
2 4 3
fumes evolve. Cool, wash down the beaker with water, and
12.3 Aspirate the blank and standards and record the instru-
dilute to 1 L with water. A purchased copper stock solution of
ment readings. Aspirate HNO (1 + 499) (11.5) between each
appropriate known purity is also acceptable.
standard.
11.2 Copper Solution, Standard (1.0 mL = 0.1 mg Cu)—
12.4 Read directly in concentration if this capability is
Dilute 100.0 mL of copper stock solution to 1 L with water.
provided with the instrument or prepare an analytical curve by
plotting the absorbance versus standard concentration for each
11.3 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
standard.
chloric acid (HCl).
NOTE 4—If a high reagent blank is obtained, distill the HCl or use a
13. Procedure
spectrograde acid.
13.1 An effective way to clean all glassware to be used for
(Warning—When HCl is distilled an azeotropic mixture is
preparation of standard solutions or in the digestion step, or
obtained (approximately 6 N HCl). Therefore, whenever con-
both, is by soaking the glassware overnight with HNO (1+1)
centrated HCl is specified for the preparation of a reagent or in
and then rinse with reagent.
the procedure, use double the volume specified if distilled HCl
is used.)
13.2 Measure 100.0 mL of a well-mixed acidified sample
into a 125-mL beaker or flask.
11.4 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
(HNO ).
NOTE 6—If only dissolved copper is to be determined, start with 13.6.
NOTE 5—If a high reagent blank is obtained, distill the HNO or use a
13.3 Add 5 mL of HCl (sp gr 1.19) (11.3) to each sample.
spectrograde acid.
13.4 Heat the samples (between 65°C and 95°C) on a steam
11.5 Nitric Acid (1 + 499)—Add 1 volume of HNO (sp gr
bath or hotplate below boiling in a well-ventilated hood until
1.42) to 499 volumes of water.
the volume has been reduced to 15 to 20 mL, making certain
11.6 Sulfuric Acid—Concentrated sulfuric acid (H SO ).
2 4 that the samples do not boil.
11.7 Sulfuric Acid (1 + 1)—Cautiously, and with constant
NOTE 7—When analyzing samples containing appreciable amounts of
stirringandcooling,add1volumeofconcentratedsulfuricacid
suspended matter, the amount of reduction in volume is left to the
(H SO , sp gr 1.84) to 1 volume of water. discretion of the analyst.
2 4
NOTE 8—Many laboratories have found block digestion systems a
11.8 Oxidant:
useful way to digest samples for trace metals analysis. Systems typically
11.8.1 Air, which has been passed through a suitable filter to
consist of either a metal or graphite block with wells to hold digestion
remove oil, water, and other foreign substances, is the usual tubes. The block temperature controller must be able to maintain unifor-
mity of temperature across all positions of the block. The digestion block
oxidant.
must be capable of maintaining a temperature between 65°C and 95°C.
11.9 Fuel:
For trace metals analysis, the digestion tubes should be constructed of
11.9.1 Acetylene—Standard, commercially available acety- 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
lene is the usual fuel. Acetone, always present in acetylene
for their intended purpose.
cylinders, can affect analytical results. The cylinder should be
replaced at 345 kPa (50 psi). (Warning—“Purified” grade 13.5 Cool and filter (11.10) the samples through a suitable
filter, such as fine-textured, acid washed, ashless paper, into
acetylene containing a special proprietary solvent rather than
acetone should not be used with poly(vinyl chloride) tubing as 100-mL volumetric flasks. Wash the filter paper two or three
times with water and adjust to volume.
weakening of the tubing walls can cause a potentially hazard-
ous situation.)
13.6 Aspirate each filtered and acidified sample and deter-
11.10 Filter Paper—Purchasesuitablefilterpaper.Typically mine its absorbance or concentration at 324.7 nm. Aspirate
the filter papers have a pore size of 0.45-µm membrane. HNO (1 + 499) (11.5) between each sample.
D1688 − 17
TABLE 1 Determination of Bias for Test Method A
TEST METHOD B—ATOMIC
Statistically ABSORPTION, CHELATION-EXTRACTION
Amount Added, Amount Found, mg
Bias, % Significant, 95 %
mg Cu/L Cu/L
Level
16. Scope
Reagent Water
4.0 4.11 +2.75 no
16.1 This test method covers the determination of dissolved
2.0 2.06 +3.0 no
and total recoverable copper in most waters and brines.
0.4 0.46 +15.0 yes
Water or Waste Water
16.2 This test method is applicable in the range from 50 to
4.0 4.03 +0.75 no
500 µg/L of copper. The range may be extended to concentra-
2.0 2.02 +1.0 no
0.4 0.41 +2.5 no tions greater than 500 µg/L by dilution of the sample.
16.3 Collaborative test data were obtained on reagent water,
river water, tap water, 50 % artificial sea water, and synthetic
NaCl brine (50 000 mg/L). The information on precision and
bias may not apply to other waters.
14. Calculation
14.1 Calculate the concentration of copper in each sample,
17. Summary of Test Method
in milligrams per litre, using an analytical curve or
17.1 Copper is determined by atomic absorption spectro-
alternatively, read directly in concentration (see 12.4).
photometry. The element, either dissolved or total recoverable,
is chelated with pyrrolidine dithiocarbamic acid and extracted
15. Precision and Bias
with chloroform. The extract is evaporated to dryness, treated
15.1 The collaborative test of this test method was per-
with hot nitric acid to destroy organic matter, dissolved in
formed by ten laboratories, five of which supplied two opera-
hydrochloricacid,anddilutedtoaspecifiedvolumewithwater.
tors each. Each of the 15 operators made determinations at
A portion of the resulting solution is then aspirated into the
three levels on three different days in samples of reagent water
air-acetylene flame of the spectrophotometer. The digestion
and water of choice for a total of 270 determinations.
procedure summarized in 8.1 is used for total recoverable
copper. The same chelation-extraction procedure is used to
15.2 These collaborative test data were obtained on reagent
determine cadmium (Test Methods D3557), cobalt (Test Meth-
grade water, river water, tap water, ground water, lake water,
ods D3558), iron (Test Methods D1068), lead (Test Methods
refinery primary treated effluent, and two untreated waste
D3559), nickel (Test Methods D1886), and zinc (Test Methods
waters. For other matrices, these data may not apply.
D1691).
15.3 Precision and bias for this test method conform to
Practice D2777 – 77, which was in place at the time of
18. Interferences
collaborative testing. Under the allowances made in 1.4 of
18.1 See Section 9.
Practice D2777 – 13, these precision and bias data do meet
existing requirements for interlaboratory studies of Committee
19. Apparatus
D19 test methods.
19.1 All apparatus described in Section 10 are required.
15.4 Precision—The single-operator and overall precision
of this test method within its designated range may be
20. Reagents and Materials
expressed as follows:
In reagent water, Type II:
20.1 Bromphenol Blue Indicator Solution (1 g/L)—Dissolve
0.1 g of bromphenol blue in 100 mL of 50 % ethanol or
S 5 0.020X10.035 (1)
O
isopropanol.
S 5 0.052X10.123 (2)
T
20.2 Chloroform (CHCl ).
In water or waste water:
20.3 Copper Solution, Stock (1.0 mL = 1.0 mg Cu)—
S 5 0.016X10.033 (3)
O
Dissolve 1.000 g of electrolytic copper contained in a 250-mL
S 5 0.060X10.039 (4)
beaker in a mixture of 15 mLof HNO (sp gr 1.42) and 15 mL
T
ofwater.Slowlyadd4mLofH SO (1 + 1)andheatuntilSO
2 4 3
where:
fumes evolve. Cool, wash down the beaker with water, and
S = single-operator precision,
O
dilute to 1 L with water. A purchased copper stock solution of
S = overall precision, and
T
appropriate known purity is acceptable.
X = determined concentration of copper, mg/L.
20.4 Copper Solution, Intermediate (1.0 mL = 10 µg Cu)—
15.5 Bias—Recoveriesofknownamountsofcopperwereas
Dilute 10.0 mL of copper stock solution and 1 mL of HNO
shown in Table 1.
(sp gr 1.42) to 1 L with water.
20.5 Copper Solution, Standard (1.0 mL = 1.0 µg Cu)—
Immediately before use, dilute 10.0 mLof copper intermediate
Supporting data have been filed at ASTM International Headquarters and may
solution to 100 mLwith water.This standard is used to prepare
beobtainedbyrequestingResearchReportRR:D19-1037.ContactASTMCustomer
Service at [e-mail]. working standards at the time of analysis.
D1688 − 17
20.6 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro- 22.3 Add 5 mL of HCl (sp gr 1.19) (20.6) to each sample.
chloric acid (HCl) (see Note 5).
22.4 Heat the samples (between 65°C and 95°C) on a steam
20.7 Hydrochloric Acid(1+2)—Add 1 volume of HCl (sp
bath or hotplate below boiling in a well-ventilated hood until
gr 1.19) to 2 volumes of water.
the volume has been reduced to 15 to 20 mL, making certain
that the samples do not boil.
20.8 Hydrochloric Acid (1 + 49)—Add 1 volume of HCl (sp
gr 1.19) to 49 volumes of water.
NOTE 10—When analyzing brine samples and samples containing
appreciable amounts of suspended matter, the amount of reduction in
20.9 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
volume is left to the discretion of the analyst.
(HNO ) (see Note 5).
NOTE 11—Many laboratories have found block digestion systems a
20.10 Pyrrolidine Dithiocarbamic Acid-Chloroform
useful way to digest samples for trace metals analysis. Systems typically
consist of either a metal or graphite block with wells to hold digestion
Reagent—Add 36 mLof pyrrolidine to 1 Lof CHCl . Cool the
tubes. The block temperature controller must be able to maintain unifor-
solution and add 30 mL of CS in small portions, swirling
mity of temperature across all positions of the block. The digestion block
between additions. Dilute to 2 Lwith CHCl . The reagent can
must be capable of maintaining a temperature between 65°C and 95°C.
be used for several months if stored in a cool, dark place.
For trace metals analysis, the digestion tubes should be constructed of
(Warning—All components of this reagent are highly toxic.
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
Carbon disulfide is also highly flammable. Prepare and use in
for their intended purpose.
a well-ventilated hood.)
22.5 Cool and filter the samples through a suitable filter
20.11 Sodium Hydroxide Solution (100 g/L)—Dissolve 100
(20.16), such as fine-textured, acid-washed, ashless paper, into
g of sodium hydroxide (NaOH) in water and dilute to 1 L.
250-mL separatory funnels. Wash the filter paper two or three
20.12 Sulfuric Acid—Concentrated sulfuric acid (H SO ).
2 4
times with water and adjust the volume to approximately 100
20.13 Sulfuric Acid (1 + 1)—Cautiously, and with constant mL.
stirringandcooling,add1volumeofconcentratedsulfuricacid
22.6 Add 2 drops of bromphenol blue indicator solution
(H SO , sp gr 1.84) to 1 volume of water.
2 4
(20.1) and mix.
20.14 Oxidant—See 11.8.
22.7 Adjust the pH by addition of NaOH (100 g/L) (20.11)
20.15 Fuel—See 11.9.
solution until a blue color persists.Add HCl (1 + 49) (20.8)by
drops until the blue color just disappears; then add 2.5 mL of
20.16 Filter Paper—See 11.10.
HCl (1 + 49) (20.8) in excess. The pH at this point should be
21. Standardization 2.3.
21.1 Prepare a blank and sufficient standards containing
NOTE 12—The pH adjustment in 22.7 may be made with a pH meter
from 0.0 to 50.0 µg of copper by diluting 0.0 to 50.0-mL
instead of using an indicator.
portions of standard copper solution (20.5) to 100 mL with
22.8 Add 10 mL of pyrrolidine dithiocarbamic acid-
water.
chloroform reagent and shake vigorously for 2 min.
21.2 When determining total recoverable copper, use
(Warning—See 20.10.)
125-mL beakers or flasks, add 0.5 mL of HNO (sp gr 1.42)
22.9 Plug the tip of the separatory funnel with cotton, allow
(20.9) and proceed as directed in 22.3 – 22.16. When deter-
the phases to separate, and drain the CHCl phase into a
mining dissolved copper, use 250-mL separatory funnels and
100-mL beaker.
proceed as directed in 22.6 – 22.16.
22.10 Repeattheextractionwith10mLofCHCl (20.2)and
21.3 Read directly in concentration if this capability is
drain the CHCl layer into the same beaker.
provided with the instrument or construct an analytical curve
by plotting the absorbances of standards versus concentration
NOTE 13—If color still remains in the CHCl extract, reextract the
of copper.
aqueous phase until the CHCl layer is colorless.
22.11 Place the beaker on a hot plate set at low heat
22. Procedure
(between 65°C and 95°C) or on a steam bath below boiling,
22.1 An effective way to clean all glassware to be used for
and evaporate to near dryness. Remove
...

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: D1688 − 12 D1688 − 17
Standard Test Methods for
Copper in Water
This standard is issued under the fixed designation D1688; 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*
1.1 These test methods cover the determination of copper in water by atomic absorption spectrophotometry. Section 34 on
Quality Control pertains to these test methods. Three test methods are included as follows:
Concentration
Test Method Sections
Range
A—Atomic Absorption, 0.05 to 5 mg/L 7 – 15
Direct
B—Atomic Absorption, 50 to 500 μg/L 16 – 24
Chelation-Extraction
C—Atomic Absorption, 5 to 100 μg/L 25 – 33
Graphite Furnace
Test Method Concentration
Range Sections
A—Atomic Absorption, 0.05 to 5 mg/L 7 – 15
Direct
B—Atomic Absorption, 50 to 500 μg/L 16 – 24
Chelation-Extraction
C—Atomic Absorption, 5 to 100 μg/L 25 – 33
Graphite Furnace
1.2 Either dissolved or total recoverable copper may be determined. Determination of dissolved copper requires filtration
through a 0.45-μm (No.(11.10 325) ) membrane filter at the time of collection. In-line membrane filtration is preferable.
1.3 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.
1.4 Three former photometric test methods were discontinued. Refer to Appendix X1 for historical information.
1.5 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. For specific hazard statements, see Note 411.3, Note 611.9.1, Note 1020.10, and Note 1622.11.
1.5 Three former photometric test methods were 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.
2. Referenced Documents
2.1 ASTM Standards:
D858 Test Methods for Manganese in Water
D1066 Practice for Sampling Steam
D1068 Test Methods for Iron in Water
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, 2012June 1, 2017. Published September 2012July 2017. Originally approved in 1959. Last previous edition approved in 20072012 as
D1688 – 07.D1688 – 12. DOI: 10.1520/D1688-12.10.1520/D1688-17.
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
D1688 − 17
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
D1687 Test Methods for Chromium in Water
D1691 Test Methods for Zinc in Water
D1886 Test Methods for Nickel in 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
D3557 Test Methods for Cadmium in Water
D3558 Test Methods for Cobalt in Water
D3559 Test Methods for Lead in Water
D3919 Practice for Measuring Trace Elements in Water by Graphite Furnace Atomic Absorption Spectrophotometry
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 Definitions—Definitions: For definitions 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 continuing calibration blank, n—a solution containing no analytes (of interest) which is used to verify blank response and
freedom from carryover.
3.2.2 continuing calibration verification, n—a solution (or set of solutions) of known concentration used to verify freedom from
excessive instrumental drift; the concentration is to cover the range of calibration curve.
3.2.3 total recoverable copper, n—a descriptive term relating to the forms of copper recovered in the acid-digestion procedure
specified in this test standard.
4. Significance and Use
4.1 Copper is found in naturally occurring minerals principally as a sulfide, oxide, or carbonate. It makes up approximately
0.01 % of the earth’s crust and is obtained commercially from such ores as chalcopyrite (CuFeS ). Copper is also found in
biological complexes such as hemocyanin.
4.2 Copper enters water supplies through the natural process of dissolution of minerals, through industrial effluents, through its
use, as copper sulfate, to control biological growth in some reservoirs and distribution systems, and through corrosion of copper
alloy water pipes. Industries whose wastewaters may contain significant concentrations of copper include mining, ammunition
production, and most metal plating and finishing operations. It may occur in simple ionic form or in one of many complexes with
such groups as cyanide, chloride, ammonia, or organic ligands.
4.3 Although its salts, particularly copper sulfate, inhibit biological growth such as some algae and bacteria, copper is
considered essential to human nutrition and is not considered a toxic chemical at concentrations normally found in water supplies.
4.4 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, where such specifications are
available. 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. 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 lessening the bias and precision of the determination. Type II water was specified at the time
of round-robin testing of this test method.
6. Sampling
6.1 Collect the sample in accordance with Practices D1066 and D3370, as applicable.
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.
D1688 − 17
6.2 Samples shall be preserved with nitric acid (HNO , sp gr 1.42) to a pH of 2 or less immediately at the time of collection,
normally about 2 mL/L. If only dissolved copper is to be determined, the sample shall be filtered through a 0.45-μm (No.(11.10
325) ) membrane filter before acidification. The holding time for samples may be calculated in accordance with Practice D4841.
NOTE 1—Alternatively, the pH may be adjusted in the laboratory if the sample is returned within 14 days. within 14 days of collection. However, acid
must be added at least 24 hours before analysis to dissolve any metals that adsorb to the container walls. This could reduce hazards of working with acids
in the field when appropriate.
TEST METHOD A—ATOMIC ABSORPTION, DIRECT
7. Scope
7.1 This test method covers the determination of dissolved and total recoverable copper in most waters and waste waters.
7.2 This test method is applicable in the range from 0.05 to 5 mg/L of copper. The range may be extended to concentrations
greater than 5 mg/L by dilution of the sample.
7.3 Collaborative test data were obtained on reagent water, river water, tap water, ground water, lake water, refinery primary
treated effluent, and two untreated waste waters. The information on precision and bias may not apply to other waters.
7. Scope
7.1 This test method covers the determination of dissolved and total recoverable copper in most waters and waste waters.
7.2 This test method is applicable in the range from 0.05 to 5 mg/L of copper. The range may be extended to concentrations
greater than 5 mg/L by dilution of the sample.
7.3 Collaborative test data were obtained on reagent water, river water, tap water, ground water, lake water, refinery primary
treated effluent, and two untreated waste waters. The information on precision and bias may not apply to other waters.
8. Summary of Test Method
8.1 Copper is determined by atomic absorption spectrophotometry. Dissolved copper in the filtered sample is aspirated directly
with no pretreatment. Total recoverable copper in the sample is aspirated following hydrochloric-nitric acid digestion and filtration.
The same digestion procedure may be used to determine total recoverable cadmium (Test Methods D3557), chromium (Test
Methods D1687), cobalt (Test Methods D3558), iron (Test Methods D1068), lead (Test Methods D3559), manganese (Test
Methods D858), nickel (Test Methods D1886), and zinc (Test Methods D1691).
9. Interferences
9.1 Sodium, potassium, sulfate, and chloride (8000 mg/L each), calcium and magnesium (5000 mg/L each), nitrate (2000 mg/L),
iron (1000 mg/L), and cadmium, lead, nickel, zinc, cobalt, manganese, and chromium (10 mg/L each) do not interfere.
9.2 Background correction or a chelation-extraction procedure (see Test Method B) may be necessary to determine low levels
of copper in some waters.
NOTE 2—Instrument manufacturers’ instructions for use of the specific correction technique should be followed.
10. Apparatus
10.1 Atomic Absorption Spectrophotometer, for use at 324.7 nm.
NOTE 3—The manufacturer’s instructions should be followed for all instrumental parameters. A wavelength other than 324.7 nm may be used if it has
been determined to be equally suitable.
10.1.1 Copper Hollow-Cathode Lamp—Multielement hollow-cathode lamps are available and have been found satisfactory.
10.2 Oxidant—See 11.8.
10.3 Fuel—See 11.9.
10.2 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 valves.
11. Reagents and Materials
11.1 Copper Solution, Stock (1.0 mL = 1.0 mg Cu)—Dissolve 1.000 g of electrolytic copper contained in a 250-mL beaker in
a mixture of 15 mL of HNO (sp gr 1.42) and 15 mL of water. Slowly add 4 mL of H SO (1 + 1) and heat until SO fumes evolve.
3 2 4 3
Cool, wash down the beaker with water, and dilute to 1 L with water. A purchased copper stock solution of appropriate known
purity is also acceptable.
11.2 Copper Solution, Standard (1.0 mL = 0.1 mg Cu)—Dilute 100.0 mL of copper stock solution to 1 L with water.
11.3 Hydrochloric Acid (sp gr 1.19)—Concentrated hydrochloric acid (HCl).
D1688 − 17
NOTE 4—If a high reagent blank is obtained, distill the HCl or use a spectrograde acid.Caution—When HCl is distilled an azeotropic mixture is obtained
(approximately 6 N HCl). Therefore, whenever concentrated HCl is specified for the preparation of a reagent or in the procedure, use double the volume
specified if distilled HCl is used.
(Warning—When HCl is distilled an azeotropic mixture is obtained (approximately 6 N HCl). Therefore, whenever
concentrated HCl is specified for the preparation of a reagent or in the procedure, use double the volume specified if distilled HCl
is used.)
11.4 Nitric Acid (sp gr 1.42)—Concentrated nitric acid (HNO ).
NOTE 5—If a high reagent blank is obtained, distill the HNO or use a spectrograde acid.
11.5 Nitric Acid (1 + 499)—Add 1 volume of HNO (sp gr 1.42) to 499 volumes of water.
11.6 Sulfuric Acid—Concentrated sulfuric acid (H SO ).
2 4
11.7 Sulfuric Acid (1 + 1)—Cautiously, and with constant stirring and cooling, add 1 volume of concentrated sulfuric acid
(H SO , sp gr 1.84) to 1 volume of water.
2 4
11.8 Oxidant:
11.8.1 Air, which has been passed through a suitable filter to remove oil, water, and other foreign substances, is the usual
oxidant.
11.9 Fuel:
11.9.1 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 should not be used with poly(vinyl chloride) tubing as weakening of the tubing
walls can cause a potentially hazardous situation.)
NOTE 6—Precaution: “Purified” grade acetylene containing a special proprietary solvent rather than acetone should not be used with poly(vinyl
chloride) tubing as weakening of the tubing walls can cause a potentially hazardous situation.
11.10 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 Prepare 100 mL each of a blank and at least four standard solutions to bracket the expected copper concentration range
of the samples to be analyzed by diluting the standard copper solution (11.2) with HNO (1 + 499 (11.5). Prepare the standards
each time the test is to be performed.performed or as determined by Practice D4841.
12.2 When determining total recoverable copper add 0.5 mL of HNO (sp gr 1.42) (11.4)and proceed as directed in 13.213.3
– 13.413.5. When determining dissolved copper proceed with 13.513.6.
12.3 Aspirate the blank and standards and record the instrument readings. Aspirate HNO (1 + 499) (11.5) between each
standard.
12.4 Prepare Read directly in concentration if this capability is provided with the instrument or prepare an analytical curve by
plotting the absorbance versus standard concentration for each standard. Alternatively, read directly in concentration from the
instrument.
13. Procedure
13.1 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 overnight with HNO (1 + 1) and then rinse with reagent.
13.2 Measure 100.0 mL of a well-mixed acidified sample into a 125-mL beaker or flask.
NOTE 6—If only dissolved copper is to be determined, start with 13.513.6.
13.3 Add 5 mL of HCl (sp gr 1.19) (11.3) to each sample.
13.4 Heat the samples (between 65°C and 95°C) on a steam bath or hotplate 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 7—When analyzing samples containing appreciable amounts of suspended matter, the amount of reduction in volume is left to the discretion of
the analyst.
NOTE 8—Many laboratories have found block digestion systems a useful way to digest samples for trace metals analysis. Systems typically consist of
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%. 0.5 %. All lots of tubes should come with a
certificate of analysis to demonstrate suitability for their intended purpose.
D1688 − 17
TABLE 1 Determination of Bias for Test Method A
Statistically
Amount Added, Amount Found, mg
Bias, % Significant, 95 %
mg Cu/L Cu/L
Level
Reagent Water
4.0 4.11 + 2.75 no
4.0 4.11 +2.75 no
2.0 2.06 + 3.0 no
2.0 2.06 +3.0 no
0.4 0.46 + 15.0 yes
0.4 0.46 +15.0 yes
Water or Waste Water
4.0 4.03 + 0.75 no
4.0 4.03 +0.75 no
2.0 2.02 + 1.0 no
2.0 2.02 +1.0 no
0.4 0.41 + 2.5 no
0.4 0.41 +2.5 no
13.5 Cool and filter (11.10) the samples through a suitable filter, such as fine-textured, acid washed, ashless paper, into 100-mL
volumetric flasks. Wash the filter paper two or three times with water and adjust to volume.
13.6 Aspirate each filtered and acidified sample and determine its absorbance or concentration at 324.7 nm. Aspirate HNO
(1 + 499) (11.5) between each sample.
14. Calculation
14.1 Calculate the concentration of copper in each sample, in milligrams per L,litre, using an analytical curve or alternatively,
read directly in concentration (see 12.4).
15. Precision and Bias
15.1 The collaborative test of this test method was performed by ten laboratories, five of which supplied two operators each.
Each of the 15 operators made determinations at three levels on three different days in samples of reagent water and water of choice
for a total of 270 determinations.
15.2 These collaborative test data were obtained on reagent grade water, river water, tap water, ground water, lake water,
refinery primary treated effluent, and two untreated waste waters. For other matrices, these data may not apply.
15.3 Precision and bias for this test method conform 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.
15.4 Precision—The single-operator and overall precision of this test method within its designated range may be expressed as
follows:
In reagent water, Type II:
S 5 0.020X10.035 (1)
O
S 5 0.052X10.123 (2)
T
In water or waste water:
S 5 0.016X10.033 (3)
O
S 5 0.060X10.039 (4)
T
where:
S = single-operator precision,
O
S = overall precision, and
T
X = determined concentration of copper, mg/L.
15.5 Bias—Recoveries of known amounts of copper were as shown in Table 1.
TEST METHOD B—ATOMIC ABSORPTION, CHELATION-EXTRACTION
16. Scope
16.1 This test method covers the determination of dissolved and total recoverable copper in most waters and brines.
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D19-1037. Contact ASTM Customer
Service at [e-mail].
D1688 − 17
16.2 This test method is applicable in the range from 50 to 500 μg/L of copper. The range may be extended to concentrations
greater than 500μ g/L by dilution of the sample.
16.3 Collaborative test data were obtained on reagent water, river water, tap water, 50 % artificial sea water, and synthetic NaCl
brine (50 000 mg/L). The information on precision and bias may not apply to other waters.
16. Scope
16.1 This test method covers the determination of dissolved and total recoverable copper in most waters and brines.
16.2 This test method is applicable in the range from 50 to 500 μg/L of copper. The range may be extended to concentrations
greater than 500 μg/L by dilution of the sample.
16.3 Collaborative test data were obtained on reagent water, river water, tap water, 50 % artificial sea water, and synthetic NaCl
brine (50 000 mg/L). The information on precision and bias may not apply to other waters.
17. Summary of Test Method
17.1 Copper is determined by atomic absorption spectrophotometry. The element, either dissolved or total recoverable, is
chelated with pyrrolidine dithiocarbamic acid and extracted with chloroform. The extract is evaporated to dryness, treated with hot
nitric acid to destroy organic matter, dissolved in hydrochloric acid, and diluted to a specified volume with water. A portion of the
resulting solution is then aspirated into the air-acetylene flame of the spectrophotometer. The digestion procedure summarized in
8.1 is used for total recoverable copper. The same chelation-extraction procedure is used to determine cadmium (Test Methods
D3557), cobalt (Test Methods D3558), iron (Test Methods D1068), lead (Test Methods D3559), nickel (Test Methods D1886), and
zinc (Test Methods D1691).
18. Interferences
18.1 See Section 9.
19. Apparatus
19.1 All apparatus described in Section 10 are required.
20. Reagents and Materials
20.1 Bromphenol Blue Indicator Solution (1 g/L)—Dissolve 0.1 g of bromphenol blue in 100 mL of 50 % ethanol or
isopropanol.
20.2 Chloroform (CHCl ).
20.3 Copper Solution, Stock (1.0 mL = 1.0 mg Cu)—Dissolve 1.000 g of electrolytic copper contained in a 250-mL beaker in
a mixture of 15 mL of HNO (sp gr 1.42) and 15 mL of water. Slowly add 4 mL of H SO (1 + 1) and heat until SO fumes evolve.
3 2 4 3
Cool, wash down the beaker with water, and dilute to 1 L with water. A purchased copper stock solution of appropriate known
purity is acceptable.
20.4 Copper Solution, Intermediate (1.0 mL = 10 μg Cu)—Dilute 10.0 mL of copper stock solution and 1 mL of HNO (sp gr
1.42) to 1 L with water.
20.5 Copper Solution, Standard (1.0 mL = 1.0 μg Cu)—Immediately before use, dilute 10.0 mL of copper intermediate solution
to 100 mL with water. This standard is used to prepare working standards at the time of analysis.
20.6 Hydrochloric Acid (sp gr 1.19)—Concentrated hydrochloric acid (HCl) (see Note 5).
20.7 Hydrochloric Acid (1 + 2)—Add 1 volume of HCl (sp gr 1.19) to 2 volumes of water.
20.8 Hydrochloric Acid (1 + 49)—Add 1 volume of HCl (sp gr 1.19) to 49 volumes of water.
20.9 Nitric Acid (sp gr 1.42)—Concentrated nitric acid (HNO ) (see Note 5).
20.10 Pyrrolidine Dithiocarbamic Acid-Chloroform Reagent—Add 36 mL of pyrrolidine to 1 L of CHCl . Cool the solution and
add 30 mL of CS in small portions, swirling between additions. Dilute to 2 L with CHCl . The reagent can be used for several
2 3
months if stored in a cool, dark place. (Warning—All components of this reagent are highly toxic. Carbon disulfide is also highly
flammable. Prepare and use in a well-ventilated hood.)
NOTE 10—Warning: All components of this reagent are highly toxic. Carbon disulfide is also highly flammable. Precaution—Prepare and use in a
well-ventilated hood.
20.11 Sodium Hydroxide Solution (100 g/L)—Dissolve 100 g of sodium hydroxide (NaOH) in water and dilute to 1 L.
20.12 Sulfuric Acid—Concentrated sulfuric acid (H SO ).
2 4
20.13 Sulfuric Acid (1 + 1)—Cautiously, and with constant stirring and cooling, add 1 volume of concentrated sulfuric acid
(H SO , sp gr 1.84) to 1 volume of water.
2 4
D1688 − 17
20.14 Oxidant—See 11.8.
20.15 Fuel—See 11.9.
20.16 Filter Paper—See 11.10.
21. Standardization
21.1 Prepare a blank and sufficient standards containing from 0.0 to 50.0 μg of copper by diluting 0.0 to 50.0-mL portions of
standard copper solution (20.5) to 100 mL with water.
21.2 When determining total recoverable copper, use 125-mL beakers or flasks, add 0.5 mL of HNO (sp gr 1.42) (20.9) and
proceed as directed in 22.222.3 – 22.1522.16. When determining dissolved copper, use 250-mL separatory funnels and proceed
as directed in 22.522.6 – 22.1522.16.
21.3 Construct Read directly in concentration if this capability is provided with the instrument or construct an analytical curve
by plotting the absorbances of standards versus concentration of copper. Alternatively, read directly in concentration from the
instrument.
22. Procedure
22.1 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 overnight with HNO (1 + 1) and then rinse with reagent.
22.2 Measure a volume of a well-mixed acidified sample containing less than 50.0 μg of copper (100 mL maximum) into a
125-mL beaker or flask and adjust the volume to 100 mL with water.
NOTE 9—If only dissolved copper is to be determined measure a volume of filtered and acidified sample containing less than 50.0 μg of copper (100-mL
maximum) into a 250-mL separatory funnel, and begin with 22.522.6.
22.3 Add 5 mL of HCl (sp gr 1.19) (20.6) to each sample.
22.4 Heat the samples (between 65°C and 95°C) on a steam bath or hotplate 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 10—When analyzing brine samples and samples containing appreciable amounts of suspended matter, the amount of reduction in volume is left
to the discretion of the analyst.
NOTE 11—Many laboratories have found block digestion systems a useful way to digest samples for trace metals analysis. Systems typically consist
of 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%. 0.5 %. All lots of tubes should come with a
certificate of analysis to demonstrate suitability for their intended purpose.
22.5 Cool and filter the samples through a suitable filter, filter (20.16), such as fine-textured, acid-washed, ashless paper, into
250-mL separatory funnels. Wash the filter paper two or three times with water and adjust the volume to approximately 100 mL.
22.6 Add 2 drops of bromphenol blue indicator solution (20.1) and mix.
22.7 Adjust the pH by addition of NaOH (100 g/L) (20.11) solution until a blue color persists. Add HCl (1 + 49) (20.8) by drops
until the blue color just disappears; then add 2.5 mL of HCl (1 + 49) (20.8) in excess. The pH at this point should be 2.3.
NOTE 12—The pH adjustment in 22.622.7 may be made with a pH meter instead of using an indicator.
22.8 Add 10 mL of pyrrolidine dithiocarbamic acid-chloroform reagent and shake vigorously for 2 min. (Warning—See
20.10.Warning)—See Note 10.)
22.9 Plug the tip of the separatory funnel with cotton, allow the phases to
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