ASTM D1691-17

Standard Test Methods for Zinc in Water

SIGNIFICANCE AND USE
4.1 Zinc is an essential and beneficial element in body growth. Concentrations above 5 mg/L can cause a bitter astringent taste and opalescence in alkaline waters. The zinc concentration of U.S. drinking waters varies between 0.06 and 7.0 mg/L with a mean of 1.33 mg/L. Zinc most commonly enters the domestic water supply from deterioration of galvanized iron and dezincification of brass. Zinc in water also may result from industrial water pollution.3  
4.2 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 zinc in water. Section 26 on Quality Control pertains to these test methods. Two test methods are given as follows:    
Test Method  
Concentration Range  
Sections  
A—Atomic Absorption, Direct  
0.05 to 2 mg/L  
8 – 16  
B—Atomic Absorption,
Chelation-Extraction  
20 to 200 μg/L  
17 – 25  
1.2 Either dissolved or total recoverable zinc may be determined.  
1.3 These test methods have been used successfully with reagent grade water. See the specific test method for applicability to other matrices. It is the user's responsibility to assure the validity of these test methods in other matrices.  
1.4 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.  
1.5 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 Section 6 and 12.7.1, 21.7, 23.10.  
1.6 Two former colorimetric test methods were discontinued. Refer to Appendix X1 for historical information.  
1.7 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

• Replaces: ASTM D1691-12 - Standard Test Methods for Zinc in Water
• Effective Date: 01-Jun-2017
• Refers: ASTM D3558-15(2023) - Standard Test Methods for Cobalt in Water
• Effective Date: 01-Dec-2023
• 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 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 D5673-15 - Standard Test Method for Elements in Water by Inductively Coupled Plasma—Mass Spectrometry
• Effective Date: 01-Jul-2015
• Refers: ASTM D3558-15 - Standard Test Methods for Cobalt in Water
• Effective Date: 01-Feb-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 D858-12 - Standard Test Methods for Manganese in Water
• Effective Date: 01-Sep-2012
• Refers: ASTM D3557-12 - Standard Test Methods for Cadmium in Water
• Effective Date: 01-Sep-2012
• Refers: ASTM D2777-12 - Standard Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
• Effective Date: 15-Jun-2012
• Refers: ASTM D1976-12 - Standard Test Method for Elements in Water by Inductively-Coupled Argon Plasma Atomic Emission Spectroscopy
• Effective Date: 01-Mar-2012

Overview

ASTM D1691-17: Standard Test Methods for Zinc in Water provides standardized procedures for the determination of zinc concentrations in various types of water. Developed by ASTM International, this standard is essential for laboratories, water utilities, and industries concerned with water quality monitoring and regulatory compliance. The standard describes two principal test methods using atomic absorption spectrophotometry: the direct method (for higher concentrations), and the chelation-extraction method (for trace-level determination). Both dissolved and total recoverable zinc can be measured following these guidelines, ensuring high accuracy and cross-laboratory consistency.

Key Topics

• Purpose and Scope
  • Describes procedures for measuring zinc in water, applicable to a broad range of water sources including reagent water, tap water, river water, ground water, and wastewater.
  • Addresses significance, such as zinc’s essential role in human nutrition and potential taste or opalescence issues at concentrations above 5 mg/L.
  • Covers both dissolved and total recoverable forms of zinc.
• Test Methods
  • Test Method A: Atomic Absorption, Direct
    • Suitable for zinc concentrations between 0.05 and 2 mg/L.
  • Test Method B: Atomic Absorption, Chelation-Extraction
    • Applicable for trace zinc concentrations from 20 to 200 μg/L.
  • Both methods provide precision and bias data to ensure reliability.
• Quality Control
  • Emphasizes laboratory quality control measures, including calibration, method blanks, laboratory control samples, matrix spikes, and the use of independent reference materials.
  • Outlines requirements for calibration verification and standardization to maintain instrument accuracy.
• Sample Collection and Preservation
  • Recommends acid preservation of samples and filtration for dissolved zinc measurements.
  • Discusses appropriate holding times and field or laboratory pH adjustments to maintain sample integrity.
• Health and Safety Considerations
  • Stresses the need to follow appropriate health, safety, and regulatory practices due to the use of hazardous chemicals and reagents.

Applications

• Drinking Water Analysis
  For public health and regulatory compliance, water utilities use ASTM D1691-17 to monitor zinc concentrations in drinking water supplies, ensuring they remain within acceptable taste and safety thresholds.

• Industrial Wastewater Monitoring
  Industries employ these methods to assess zinc discharge in effluents, supporting environmental compliance and pollution control.

• Environmental Water Testing
  Laboratories and agencies evaluate surface and groundwater samples for zinc contamination potentially arising from industrial, agricultural, or urban sources.

• Quality Assurance in Water Treatment
  Facilities may use ASTM D1691-17 procedures to verify the effectiveness of water treatment processes in reducing zinc levels.

The standardized test methods provide precise, reproducible results and are widely referenced in water quality monitoring programs, facilitating data comparability and regulatory reporting.

Related Standards

• ASTM D5673 – Test Method for Elements in Water by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)
• ASTM D1976 – Test Method for Elements in Water by Inductively Coupled Argon Plasma Atomic Emission Spectroscopy (ICP-AES)
• ASTM D858 – Test Methods for Manganese in Water
• ASTM D1068 – Test Methods for Iron in Water
• ASTM D1688 – Test Methods for Copper in Water
• ASTM D3559 – Test Methods for Lead in Water
• ASTM D1193 – Specification for Reagent Water

These related standards complement ASTM D1691-17 in comprehensive water analysis, supporting the determination of various metal constituents in water matrices.

---

Keywords: ASTM D1691, zinc in water, water quality, atomic absorption spectrophotometry, chelation-extraction, dissolved zinc, total recoverable zinc, laboratory quality control, water testing standards, drinking water compliance, industrial wastewater 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: D1691 − 17
Standard Test Methods for
Zinc in Water
This standard is issued under the fixed designation D1691; 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 zinc in
D858 Test Methods for Manganese in Water
water. Section 26 on Quality Control pertains to these test
D1066 Practice for Sampling Steam
methods. Two test methods are given as follows:
D1068 Test Methods for Iron in Water
Concentration
Test Method Sections
D1129 Terminology Relating to Water
Range
A—Atomic Absorption, Direct 0.05 to 2 mg/L 8–16
D1193 Specification for Reagent Water
B—Atomic Absorption, 20 to 200 µg/L 17–25
D1687 Test Methods for Chromium in Water
Chelation-Extraction
D1688 Test Methods for Copper in Water
1.2 Either dissolved or total recoverable zinc may be deter-
D1886 Test Methods for Nickel in Water
mined.
D1976 Test Method for Elements in Water by Inductively-
Coupled Argon Plasma Atomic Emission Spectroscopy
1.3 These test methods have been used successfully with
D2777 Practice for Determination of Precision and Bias of
reagent grade water. See the specific test method for applica-
Applicable Test Methods of Committee D19 on Water
bility to other matrices. It is the user’s responsibility to assure
D3370 Practices for Sampling Water from Closed Conduits
the validity of these test methods in other matrices.
D3557 Test Methods for Cadmium in Water
1.4 The values stated in SI units are to be regarded as
D3558 Test Methods for Cobalt in Water
standard. The values given in parentheses are mathematical D3559 Test Methods for Lead in Water
conversion to inch-pound units that are provided for informa- D4841 Practice for Estimation of Holding Time for Water
Samples Containing Organic and Inorganic Constituents
tion only and are not considered standard.
D5673 Test Method for Elements in Water by Inductively
1.5 This standard does not purport to address all of the
Coupled Plasma—Mass Spectrometry
safety concerns, if any, associated with its use. It is the
D5810 Guide for Spiking into Aqueous Samples
responsibility of the user of this standard to establish appro-
D5847 Practice for Writing Quality Control Specifications
priate safety and health practices and determine the applica-
for Standard Test Methods for Water Analysis
bility of regulatory limitations prior to use. For specific hazard
statements, see Section 6 and 12.7.1, 21.7, 23.10.
3. Terminology
1.6 Two former colorimetric test methods were discontin-
3.1 Definitions:
ued. Refer to Appendix X1 for historical information.
3.1.1 For definitions of terms used in this standard, refer to
1.7 This international standard was developed in accor-
Terminology D1129.
dance with internationally recognized principles on standard-
3.2 Definitions:
ization established in the Decision on Principles for the
3.2.1 continuing calibration blank, n—a solution containing
Development of International Standards, Guides and Recom-
no analytes (of interest) which is used to verify blank response
mendations issued by the World Trade Organization Technical
and freedom from carryover.
Barriers to Trade (TBT) Committee.
3.2.2 continuing calibration verification, n—a solution (or
setofsolutions)ofknownconcentrationusedtoverifyfreedom
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 June 1, 2017. Published June 2017. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1959. Last previous edition approved in 2012 as D1691 – 12. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D1691-17. 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
D1691 − 17
from excessive instrumental drift; the concentration is to cover a 0.45-µm membrane filter before acidification. The holding
the range of calibration curve. timeforsamplesmaybecalculatedinaccordancewithPractice
D4841.
3.2.3 totalrecoverablezinc,n—adescriptiveanalyticalterm
relating to the recoverable form of zinc that is determinable by
NOTE 1—Alternatively, the pH may be adjusted in the laboratory within
the digestion method that is included in this test standard. 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
4. Significance and Use
appropriate.
4.1 Zinc is an essential and beneficial element in body
growth. Concentrations above 5 mg/L can cause a bitter TEST METHOD A—ATOMIC ABSORPTION, DIRECT
astringent taste and opalescence in alkaline waters. The zinc
8. Scope
concentration of U.S. drinking waters varies between 0.06 and
8.1 This test method covers the determination of dissolved
7.0 mg/L with a mean of 1.33 mg/L. Zinc most commonly
and total recoverable zinc in most waters and wastewaters.
enters the domestic water supply from deterioration of galva-
nized iron and dezincification of brass. Zinc in water also may
8.2 This test method is applicable in the range from 0.05 to
result from industrial water pollution.
2.0 mg/Lof zinc.The range may be extended to concentrations
greater than 2.0 mg/L by dilution of the sample.
4.2 ICP-MS or ICP-AES may also be appropriate but at a
higher instrument cost. See Test Methods D5673 and D1976.
8.3 This test method has been used successfully with
reagent grade water, river water, wastewater, ground water, tap
5. Purity of Reagents
water, lake water, refinery effluent. The information on preci-
5.1 Reagent grade chemicals shall be used in all tests.
sion and bias may not apply to other waters.
Unless otherwise indicated, it is intended that all reagents shall
9. Summary of Test Method
conform to the specifications of the Committee on Analytical
Reagents of the American Chemical Society, where such 9.1 Zinc is determined by atomic absorption spectropho-
specifications are available. Other grades may be used, pro- tometry. Dissolved zinc is determined by aspirating a portion
vided it is first ascertained that the reagent is of sufficiently of the filtered and preserved sample directly with no pretreat-
high purity to permit its use without lessening the accuracy of ment. Total recoverable zinc is determined by aspirating the
the determination. sample following hydrochloric-nitric acid digestion and filtra-
tion. The same digestion procedure is used to determine total
5.2 Purity of Water—Unless otherwise indicated, references
recoverable cadmium (Test Methods D3557), chromium, (Test
towatershallbeunderstoodtomeanreagentwaterconforming
Methods D1687), cobalt (Test Methods D3558), copper (Test
to Specification D1193, Type I. Other reagent water types may
Methods D1688), iron (Test Methods D1068), lead (Test
be used, provided it is first ascertained that the water is of
Methods D3559), manganese (Test Methods D858), and nickel
sufficiently high purity to permit its use without adversely
(Test Methods D1886).
affecting the bias and precision of the test method. Type II
water was specified at the time of round-robin testing of this
10. Interferences
test method.
10.1 Sodium, potassium, sulfate, and chloride (9000 mg/L
each),calciumandmagnesium(4000mg/Leach),nitrate(2000
6. Hazards
mg/L), and cadmium, lead, copper, nickel, cobalt, and chro-
6.1 Although zinc is nontoxic to man, these test methods
mium (10 mg/L each) do not interfere.
require the use of certain other toxic and hazardous reagents
10.2 Background correction or a chelation-extraction proce-
and materials. Each should be used with care and exerting
dure (see Test Method B) may be necessary to determine low
proper precautions.
levels of zinc in some waters.
7. Sampling
NOTE 2—Instrument manufacturers’ instructions for use of the specific
correction technique should be followed.
7.1 Collect the sample in accordance with Practices D1066
and D3370, as applicable.
11. Apparatus
7.2 Samples shall be preserved with nitric acid (HNO ) (sp
11.1 Atomic Absorption Spectrophotometer, for use at 213.9
gr 1.42) to a pH of 2 or less immediately at the time of
nm.
collection, normally about 2 mL/L of HNO . If only dissolved
NOTE 3—The manufacturer’s instructions should be followed for all
zinc is to be determined, the sample, shall be filtered through
instrumental parameters.Wavelengths other than 213.9 nm may be used if
they have been determined to be equally suitable.
“Standard Methods for the Examination of Water and Wastewater,” 16th
11.1.1 Zinc Light Source—Hollow-cathode lamps or elec-
edition, 1985, APHA, AWWA-WPCF.
trodeless discharge lamps have been found satisfactory.
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
11.2 Pressure-Reducing Valves—The supplies of fuel and
listed by the American Chemical Society, see Annual Standards for Laboratory
oxidant shall be maintained at pressures somewhat higher than
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
the controlled operating pressure of the instrument by suitable
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. valves.
D1691 − 17
12. Reagents and Materials blankandstandardsolutionshasbeencompletedin14.5,return
to 13.3 to complete the standardization for total recoverable
12.1 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
determinations. To determine dissolved zinc, proceed with
chloric acid (HCl).
13.3.
NOTE 4—If the reagent blank concentration is greater than the method
13.3 Aspirate the blank and standards, and record the
detection limit, distill the HCl or use a spectrograde acid.
absorbance or concentration of each at 213.9 nm. Aspirate
(Warning—When HCl is distilled an azeotropic mixture is
HNO (1 +499) between each standard.
obtained (approximately 6 N HCl). Therefore, whenever con-
13.4 Read directly in concentration if this capability is
centrated HCl is specified in the preparation of a reagent or in
provided with the instrument or prepare an analytical curve by
the procedure, use double the amount specified if a distilled
plotting the absorbance versus concentration for each standard.
acid is used.)
12.2 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
14. Procedure
(HNO ).
14.1 An effective way to clean all glassware to be used for
NOTE 5—If the reagent blank concentration is greater than the method
preparation of standard solutions or in the digestion step, or
detection limit, distill the HNO or use a trace metal grade acid.
both, is by soaking the glassware overnight with HNO (1+1)
12.3 Nitric Acid (1 +499)—Add 1 volume of HNO (sp gr and then rinse with reagent.
1.42) to 499 volumes of water.
14.2 Measure 100.0 mL of a well-mixed acidified sample
12.4 Zinc Solution, Stock (1 mL = 1.0 mg Zn)—Dissolve into a 125-mL beaker or flask.
1.245gofzincoxide(ZnO)inamixtureof10mLofHNO (sp
NOTE 6—If only dissolved zinc is to be determined, start with 14.6.
gr 1.42) and 10 mL of water. Dilute to 1 L with water. A
14.3 Add 5 mL of HCl (sp gr 1.19) to each sample.
purchased zinc stock solution of appropriate known purity is
also acceptable.
14.4 Heat the samples (between 65°C and 95°C) on a steam
bath or hotplate below boiling in a well-ventilated hood until
12.5 Zinc Solution, Standard (1 mL = 0.1 mg Zn)—Dilute
the volume has been reduced to 15 to 20 mL, making certain
100.0 mL of the zinc stock solution and 1 mL of HNO (sp gr
that the samples do not boil.
1.42) to 1 L with water.
NOTE 7—For samples with appreciable amounts of suspended matter or
12.6 Oxidant:
dissolved solids, the amount of reduction in the volume is left to the
12.6.1 Air, which has been passed through a suitable filter to
discretion of the analyst.
remove oil, water, and other foreign substances, is the usual
NOTE 8—Many laboratories have found block digestion systems a
oxidant.
useful way to digest samples for trace metals analysis. Systems typically
consist of either a metal or graphite block with wells to hold digestion
12.7 Fuel:
tubes. The block temperature controller must be able to maintain unifor-
12.7.1 Acetylene—Standard, commercially available acety-
mity of temperature across all positions of the block. The digestion block
lene is the usual fuel. Acetone, always present in acetylene
must be capable of maintaining a temperature between 65°C and 95°C.
For trace metals analysis, the digestion tubes should be constructed of
cylinders, can affect analytical results. The cylinder should be
polypropylene and have a volume accuracy of at least 0.5 %. All lots of
replaced at 345 kPa (50 psi). (Warning—“Purified” grade
tubes should come with a certificate of analysis to demonstrate suitability
acetylene containing a special proprietary solvent rather than
for their intended purpose.
acetone should not be used with poly(vinyl chloride) tubing as
14.5 Cool and filter the samples through a suitable filter
weakening of the tubing walls can cause a potentially hazard-
(12.8), such as fine-textured, acid-washed, ashless paper, into
ous situation.)
100-mL volumetric flasks. Wash the filter paper two or three
12.8 Filter Paper—Purchase suitable filter paper. Typically
times with water and adjust to volume.
the filter papers have a pore size of 0.45-µm membrane.
14.6 Aspirate each filtered and acidified sample and stan-
Material such as fine-textured, acid-washed, ashless paper, or
dard and determine its absorbance or concentration at 213.9
glass fiber paper are acceptable. The user must first ascertain
nm. Atomize HNO (1 +499) between each sample and stan-
that the filter paper is of sufficient purity to use without
dard.
adversely affecting the bias and precision of the test method.
15. Calculation
13. Standardization
15.1 Calculate the concentration of zinc in each sample, in
13.1 Prepare 100 mL each of a blank and at least four
milligrams per litre, using the analytical curve prepared in 13.4
standard solutions to bracket the expected zinc concentration
or read directly in concentration.
range of the samples to be analyzed by diluting the standard
zincsolution(12.5)withHNO (1 +499).Preparethestandards
16. Precision and Bias
each time the test is to be performed and select so as to give
16.1 The overall precision and bias of this test method,
zero,middle,andmaximumpointsforananalyticalcurveoras
within its designated range, is shown in Table 1.
determined by Practice D4841.
13.2 When determining total recoverable zinc, add 0.5 mL
Supporting data have been filed at ASTM International Headquarters and may
of HNO (sp gr 1.42) to each blank and standard solution and
3 beobtainedbyrequestingResearchReportRR:D19-1039.ContactASTMCustomer
proceed as directed in 14.3 – 14.5. After the digestion of the Service at [e-mail].
D1691 − 17
TABLE 1 Determination of Precision and Bias for Zinc by Atomic
21. Reagents and Materials
Absorption, Direct
21.1 Bromphenol Blue Indicator Solution (1 g/L)—
Amount Amount Statistically
S , S , %,
T O Dissolve 0.1 g of bromphenol blue in 100 mL of 50 % ethanol
Added, Found, Significant,
mg/L mg/L Bias
mg/L mg/L 95 % Level
or isopropranol.
Reagent Water
21.2 Chloroform (CHCl ).
0.16 0.172 0.052 0.038 +7.5 No
0.80 0.798 0.068 0.034 −0.2 No
21.3 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
1.50 1.459 0.107 0.041 −2.7 Yes
chloric acid (HCl) (see Note 3).
Water of Choice
0.16 0.172 0.041 0.033 +7.5 Yes
21.4 Hydrochloric Acid (1 +2)—Add 1 volume of hydro-
0.80 0.796 0.081 0.047 −0.5 No
chloric acid (HCl), sp gr 1.19, to 2 volumes of water.
1.50 1.446 0.098 0.060 −3.6 Yes
21.5 Hydrochloric Acid (1 +49)—Add 1 volume of hydro-
chloric acid (HCl) sp gr 1.19, to 49 volumes of water.
21.6 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
16.2 These collaborative test data were obtained from
(HNO ) (see Note 5).
eleven laboratories on reagent grade, river, lake, ground and
21.7 Pyrrolidine Dithiocarbamic Acid-Chloroform
effluent waters. For other waters these data may not apply.
Reagent—Add 36 mLof pyrrolidine to 1 Lof CHCl . Cool the
16.3 Precision and bias for this test method conform to
solution and add 30 mL of CS in small portions, swirling
Practice D2777 – 77, which was in place at the time of
between additions. Dilute to 2 L with CHCl . The reagent can
collaborative testing. Under the allowances made in 1.4 of
be used for several months if stored in a cool, dark place.
Practice D2777 – 13, these precision and bias data do meet
(Warning—All components of this reagent are highly toxic.
existing requirements for interlaboratory studies of Committee
Carbon disulfide is also highly flammable. Prepare and use in
D19 test methods.
a well-ventilated hood. Avoid inhalation and direct contact.)
TEST METHOD B—ATOMIC ABSORPTION,
21.8 Sodium Hydroxide Solution (100 g/L)—Dissolve 100 g
CHELATION–EXTRACTION
of sodium hydroxide (NaOH) in water and dilute to 1 L.
21.9 Zinc Solution, Stock (1.0 mL = 1.0 mg Zn)—See 12.4.
17. Scope
21.10 Zinc Solution, Intermediate (1.0 mL = 0.1 mg Zn)—
17.1 This test method
...

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: D1691 − 12 D1691 − 17
Standard Test Methods for
Zinc in Water
This standard is issued under the fixed designation D1691; 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 zinc in water. Section 26 on Quality Control pertains to these test methods.
Two test methods are given as follows:
Concentration
Test Method Sections
Range
A—Atomic Absorption, Direct 0.05 to 2 mg/L 8 – 16
B—Atomic Absorption, 20 to 200 μg/L 17 – 25
Chelation-Extraction
Test Method Concentration Sections
Range
A—Atomic Absorption, Direct 0.05 to 2 mg/L 8 – 16
B—Atomic Absorption, 20 to 200 μg/L 17 – 25
Chelation-Extraction
1.2 Either dissolved or total recoverable zinc may be determined.
1.3 These test methods have been used successfully with reagent grade water. See the specific test method for applicability to
other matrices. It is the user’s responsibility to assure the validity of these test methods in other matrices.
1.4 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.
1.5 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 Section 6 and Note 612.7.1, Note 1021.7, and23.10Note 16.
1.6 Two former colorimetric test methods were discontinued. Refer to Appendix X1 for historical information.
1.7 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
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
D1687 Test Methods for Chromium in Water
D1688 Test Methods for Copper 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 2012June 2017. Originally approved in 1959. Last previous edition approved in 20022012 as
D1691 – 02D1691 – 12.(2007)E01. DOI: 10.1520/D1691-12.10.1520/D1691-17.
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
D1691 − 17
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
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:
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 zinc, n—an arbitrarya descriptive analytical term relating to the recoverable form of zinc that is
determinable by the digestion method that is included in the Procedure.this test standard.
4. Significance and Use
4.1 Zinc is an essential and beneficial element in body growth. Concentrations above 5 mg/L can cause a bitter astringent taste
and opalescence in alkaline waters. The zinc concentration of U.S. drinking waters varies between 0.06 and 7.0 mg/L with a mean
of 1.33 mg/L. Zinc most commonly enters the domestic water supply from deterioration of galvanized iron and dezincification of
brass. Zinc in water also may result from industrial water pollution.
4.2 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. 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 adversely affecting the bias and precision of the test method. Type II water was specified at
the time of round-robin testing of this test method.
6. Hazards
6.1 Although zinc is nontoxic to man, these test methods require the use of certain other toxic and hazardous reagents and
materials. Each should be used with care and exerting proper precautions.
7. Sampling
7.1 Collect the sample in accordance with PracticePractices D1066 and Practices D3370, as applicable.
7.2 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 of HNO . If only dissolved zinc is to be determined, the sample, shall be filtered through a 0.45-μm
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
“Standard Methods for the Examination of Water and Wastewater,” 16th edition, 1985, APHA, AWWA-WPCF.
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.
D1691 − 17
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
8. Scope
8.1 This test method covers the determination of dissolved and total recoverable zinc in most waters and wastewaters.
8.2 This test method is applicable in the range from 0.05 to 2.0 mg/L of zinc. The range may be extended to concentrations
greater than 2.0 mg/L by dilution of the sample.
8.3 This test method has been used successfully with reagent grade water, river water, wastewater, ground water, tap water, lake
water, refinery effluent. The information on precision and bias may not apply to other waters.
8. Scope
8.1 This test method covers the determination of dissolved and total recoverable zinc in most waters and wastewaters.
8.2 This test method is applicable in the range from 0.05 to 2.0 mg/L of zinc. The range may be extended to concentrations
greater than 2.0 mg/L by dilution of the sample.
8.3 This test method has been used successfully with reagent grade water, river water, wastewater, ground water, tap water, lake
water, refinery effluent. The information on precision and bias may not apply to other waters.
9. Summary of Test Method
9.1 Zinc is determined by atomic absorption spectrophotometry. Dissolved zinc is determined by aspirating a portion of the
filtered and preserved sample directly with no pretreatment. Total recoverable zinc is determined by aspirating the sample
following hydrochloric-nitric acid digestion and filtration. The same digestion procedure is used to determine total recoverable
cadmium (Test Methods D3557), chromium, (Test Methods D1687), cobalt (Test Methods D3558), copper (Test Methods D1688),
iron (Test Methods D1068), lead (Test Methods D3559), manganese (Test Methods D858), and nickel (Test Methods D1886).
10. Interferences
10.1 Sodium, potassium, sulfate, and chloride (9000 mg/L each), calcium and magnesium (4000 mg/L each), nitrate (2000
mg/L), and cadmium, lead, copper, nickel, cobalt, and chromium (10 mg/L each) do not interfere.
10.2 Background correction or a chelation-extraction procedure (see Test Method B) may be necessary to determine low levels
of zinc in some waters.
NOTE 2—Instrument manufacturers’ instructions for use of the specific correction technique should be followed.
11. Apparatus
11.1 Atomic Absorption Spectrophotometer , Spectrophotometer, for use at 213.9 nm.
NOTE 3—The manufacturer’s instructions should be followed for all instrumental parameters. Wavelengths other than 213.9 nm may be used if they
have been determined to be equally suitable.
11.1.1 Zinc Light Source—Hollow-cathode lamps or electrodeless discharge lamps have been found satisfactory.
11.2 Oxidant—See 12.6.
11.3 Fuel—See 12.7.
11.2 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.
12. Reagents and Materials
12.1 Hydrochloric Acid (sp gr 1.19)—Concentrated hydrochloric acid (HCl).
NOTE 4—If the reagent blank concentration is greater than the method detection limit, distill the HCl or use a spectrograde acid.Warning—When HCl
is distilled an azeotropic mixture is obtained (approximately 6 N HCl). Therefore, whenever concentrated HCl is specified in the preparation of a reagent
or in the procedure, use double the amount specified if a distilled acid is used.
(Warning—When HCl is distilled an azeotropic mixture is obtained (approximately 6 N HCl). Therefore, whenever
concentrated HCl is specified in the preparation of a reagent or in the procedure, use double the amount specified if a distilled acid
is used.)
12.2 Nitric Acid (sp gr 1.42)—Concentrated nitric acid (HNO ).
NOTE 5—If the reagent blank concentration is greater than the method detection limit, distill the HNO or use a trace metal grade acid.
12.3 Nitric Acid (1 +499)—Add 1 volume of HNO (sp gr 1.42) to 499 volumes of water.
D1691 − 17
12.4 Zinc Solution, Stock (1 mL = 1.0 mg Zn)—Dissolve 1.245 g of zinc oxide (ZnO) in a mixture of 10 mL of HNO (sp gr
1.42) and 10 mL of water. Dilute to 1 L with water. A purchased zinc stock solution of appropriate known purity is also acceptable.
12.5 Zinc Solution, Standard (1 mL = 0.1 mg Zn)—Dilute 100.0 mL of the zinc stock solution and 1 mL of HNO (sp gr 1.42)
to 1 L with water.
12.6 Oxidant:
12.6.1 Air, which has been passed through a suitable filter to remove oil, water, and other foreign substances, is the usual
oxidant.
12.7 Fuel:
12.7.1 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—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.
12.8 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.
13. Standardization
13.1 Prepare 100 mL each of a blank and at least four standard solutions to bracket the expected zinc concentration range of
the samples to be analyzed by diluting the standard zinc solution (12.5) with HNO (1 +499). Prepare the standards each time the
test is to be performed and select so as to give zero, middle, and maximum points for an analytical curve.curve or as determined
by Practice D4841.
13.2 When determining total recoverable zinc, add 0.5 mL of HNO (sp gr 1.42) to each blank and standard solution and
proceed as directed in 14.214.3 – 14.414.5. After the digestion of the blank and standard solutions has been completed in 14.414.5,
return to 13.3 to complete the standardization for total recoverable determinations. To determine dissolved zinc, proceed with 13.3.
13.3 Aspirate the blank and standards, and record the absorbance or concentration of each at 213.9 nm. Aspirate HNO (1 +499)
between each standard.
13.4 Prepare Read directly in concentration if this capability is provided with the instrument or prepare an analytical curve by
plotting the absorbance versus concentration for each standard. Alternatively, read directly in concentration from the instrument.
14. Procedure
14.1 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.
14.2 Measure 100.0 mL of a well-mixed acidified sample into a 125-mL beaker or flask.
NOTE 6—If only dissolved zinc is to be determined, start with 14.514.6.
14.3 Add 5 mL of HCl (sp gr 1.19) to each sample.
14.4 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—For samples with appreciable amounts of suspended matter or dissolved solids, the amount of reduction in the 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.
14.5 Cool and filter the samples through a suitable filter, filter (12.8), 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.
14.6 Aspirate each filtered and acidified sample and standard and determine its absorbance or concentration at 213.9 nm.
Atomize HNO (1 +499) between each sample and standard.
15. Calculation
15.1 Calculate the concentration of zinc in each sample, in milligrams per litre, using the analytical curve prepared in 13.4 or
read directly in concentration.
D1691 − 17
TABLE 1 Determination of Precision and Bias for Zinc by Atomic
Absorption, Direct
Amount Amount Statistically
S , S , %,
T O
Added, Found, Significant,
mg/L mg/L Bias
mg/L mg/L 95 % Level
Reagent Water
0.16 0.172 0.052 0.038 + 7.5 No
0.16 0.172 0.052 0.038 +7.5 No
0.80 0.798 0.068 0.034 −0.2 No
1.50 1.459 0.107 0.041 −2.7 Yes
Water of Choice
0.16 0.172 0.041 0.033 + 7.5 Yes
0.16 0.172 0.041 0.033 +7.5 Yes
0.80 0.796 0.081 0.047 −0.5 No
1.50 1.446 0.098 0.060 −3.6 Yes
16. Precision and Bias
16.1 The overall precision and bias of this test method, within its designated range, is shown in Table 1.
16.2 These collaborative test data were obtained from eleven laboratories on reagent grade, river, lake, ground and effluent
waters. For other waters these data may not apply.
16.3 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.
TEST METHOD B—ATOMIC ABSORPTION, CHELATION–EXTRACTION
17. Scope
17.1 This test method covers the determination of dissolved and total recoverable zinc in most waters and brines.
17.2 This test method is applicable in the range from 20 to 200 μg/L of zinc.
17.3 This test method has been used successfully with reagent grade water, river water, wastewater, ground water, tap water,
lake water, refinery effluent. The information on precision and bias may not apply to other waters.
17. Scope
17.1 This test method covers the determination of dissolved and total recoverable zinc in most waters and brines.
17.2 This test method is applicable in the range from 20 to 200 μg/L of zinc.
17.3 This test method has been used successfully with reagent grade water, river water, wastewater, ground water, tap water,
lake water, refinery effluent. The information on precision and bias may not apply to other waters.
18. Summary of Test Method
18.1 Zinc 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. The resulting solution
is then aspirated into the air-acetylene flame of the spectrophotometer. The digestion procedure summarized in 9.1 is used when
determining total recoverable zinc. The same chelation-extraction procedure is used to determine total recoverable cadmium (Test
Methods D3557), cobalt (Test Methods D3558), copper (Test Methods D1688), iron (Test Methods D1068), lead (T
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