ASTM D2972-15(2023)

Standard Test Methods for Arsenic in Water

SIGNIFICANCE AND USE
4.1 Herbicides, insecticides, and many industrial effluents contain arsenic and are potential sources of water pollution. Arsenic is significant because of its adverse physiological effects on humans.
SCOPE
1.1 These test methods2 cover the photometric and atomic absorption determination of arsenic in most waters and wastewaters. Three test methods are given as follows:    
Concentration
Range  
Sections  
Test Method A—Silver Diethyldithio-
carbamate Colorimetric  
5 μg/L to 250 μg/L  
7 to 16  
Test Method B—Atomic Absorption,
Hydride Generation  
1 μg/L to 20 μg/L  
17 to 26  
Test Method C—Atomic Absorption,
Graphite Furnace  
5 μg/L to 100 μg/L  
27 to 36  
1.2 The analyst should direct attention to the precision and bias statements for each test method. It is the user's responsibility to ensure the validity of these test methods for waters of untested matrices.  
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 11.1 and 20.2.  
1.5 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: 30-Nov-2023
• 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 D2972-15 - Standard Test Methods for Arsenic in Water
• Effective Date: 01-Dec-2023
• Refers: ASTM D1129-13(2020)e1 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Referred By: ASTM D4382-18 - Standard Test Method for Barium in Water, Atomic Absorption Spectrophotometry, Graphite Furnace
• Effective Date: 01-Dec-2023
• Referred By: ASTM D8006-16 - Standard Guide for Sampling and Analysis of Residential and Commercial Water Supply Wells in Areas of Exploration and Production (E&P) Operations
• Effective Date: 01-Dec-2023
• Referred By: ASTM D1971-16(2021)e1 - Standard Practices for Digestion of Water Samples for Determination of Metals by Flame Atomic Absorption, Graphite Furnace Atomic Absorption, Plasma Emission Spectroscopy, or Plasma Mass Spectrometry
• Effective Date: 01-Dec-2023
• Referred By: ASTM D4691-17 - Standard Practice for Measuring Elements in Water by Flame Atomic Absorption Spectrophotometry
• Effective Date: 01-Dec-2023
• Referred By: ASTM F1581-08(2020) - Standard Specification for Composition of Anorganic Bone for Surgical Implants
• Effective Date: 01-Dec-2023

Overview

ASTM D2972-15(2023): Standard Test Methods for Arsenic in Water outlines recognized laboratory procedures for determining inorganic arsenic content in various types of water and wastewater. Arsenic contamination is a critical environmental and public health concern, as it can originate from herbicides, insecticides, and industrial effluents, and is known for its adverse physiological effects on humans.

This international standard provides three validated test methods based on colorimetric and atomic absorption techniques, suitable for a broad range of arsenic concentrations. These methods play a vital role in monitoring water quality for regulatory compliance, environmental protection, and public health safety.

Key Topics

• Purpose and Significance

  • Detects and quantifies arsenic, a key contaminant in natural and industrial waters
  • Supports environmental monitoring and regulatory activities to reduce health risks

• Test Methods Covered

  • Test Method A: Silver Diethyldithiocarbamate Colorimetric (5 μg/L to 250 μg/L)
  • Test Method B: Atomic Absorption, Hydride Generation (1 μg/L to 20 μg/L)
  • Test Method C: Atomic Absorption, Graphite Furnace (5 μg/L to 100 μg/L)

• Sample Handling and Quality Control

  • Specifies preservation techniques and filtration for accurate dissolved or total recoverable arsenic analysis
  • Includes methodology for calibration, precision, and bias assessment to ensure data reliability

• Precision and Limitations

  • Encourages users to assess matrix effects for untested water types
  • Emphasizes safety and quality control throughout the analytical process

Applications

The ASTM D2972-15(2023) standard is widely used in the following contexts:

• Drinking Water and Wastewater Monitoring

  • Ensures compliance with national and international water quality standards by detecting even trace levels of arsenic

• Environmental Impact Assessments

  • Supports site assessments and ongoing monitoring for industries and agricultural operations with potential arsenic discharges

• Industrial Process Water Testing

  • Measures arsenic in process effluents to help companies meet environmental and occupational safety requirements

• Public Health Laboratories

  • Provides reliable methods to analyze water sources that could affect community health, enabling timely risk management and intervention

• Research and Regulatory Laboratories

  • Offers reproducible protocols essential for research into water pollution, toxicology, and regulatory enforcement

Related Standards

For comprehensive water analysis and quality assurance, consider referencing these related ASTM standards:

• ASTM D1129 - Terminology Relating to Water
• ASTM D1193 - Specification for Reagent Water
• ASTM D2777 - Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
• ASTM D3370 - Practices for Sampling Water from Flowing Process Streams
• ASTM D3919 - Practice for Measuring Trace Elements in Water by Graphite Furnace Atomic Absorption Spectrophotometry
• ASTM D4841 - Practice for Estimation of Holding Time for Water Samples Containing Organic and Inorganic Constituents
• ASTM D5810 - Guide for Spiking into Aqueous Samples
• ASTM D5847 - Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis

Practical Value

By following ASTM D2972-15(2023), water testing laboratories and related industries can:

• Reliably monitor arsenic pollution in varying water matrices
• Meet environmental compliance requirements
• Protect human health by identifying hazardous contamination levels
• Maintain data integrity through prescribed sample handling, calibration, and quality control procedures

Implementing these standard test methods for arsenic in water ensures accurate, repeatable, and defensible results vital for water quality management and regulatory decision-making.

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: D2972 − 15 (Reapproved 2023)
Standard Test Methods for
Arsenic in Water
This standard is issued under the fixed designation D2972; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 These test methods cover the photometric and atomic
D1129 Terminology Relating to Water
absorption determination of arsenic in most waters and waste-
D1193 Specification for Reagent Water
waters. Three test methods are given as follows:
D2777 Practice for Determination of Precision and Bias of
Concentration Sections
Applicable Test Methods of Committee D19 on Water
Range
Test Method A—Silver Diethyldithio- 5 μg ⁄L to 250 μg ⁄L 7 to 16 D3370 Practices for Sampling Water from Flowing Process
carbamate Colorimetric
Streams
Test Method B—Atomic Absorption, 1 μg ⁄L to 20 μg/L 17 to 26
D3919 Practice for Measuring Trace Elements in Water by
Hydride Generation
Test Method C—Atomic Absorption, 5 μg ⁄L to 100 μg/L 27 to 36
Graphite Furnace Atomic Absorption Spectrophotometry
Graphite Furnace
D4841 Practice for Estimation of Holding Time for Water
Samples Containing Organic and Inorganic Constituents
1.2 The analyst should direct attention to the precision and
D5810 Guide for Spiking into Aqueous Samples
bias statements for each test method. It is the user’s responsi-
D5673 Test Method for Elements in Water by Inductively
bility to ensure the validity of these test methods for waters of
Coupled Plasma—Mass Spectrometry
untested matrices.
D5847 Practice for Writing Quality Control Specifications
1.3 The values stated in SI units are to be regarded as
for Standard Test Methods for Water Analysis
standard. The values given in parentheses are mathematical
E60 Practice for Analysis of Metals, Ores, and Related
conversions to inch-pound units that are provided for informa-
Materials by Spectrophotometry
tion only and are not considered standard.
E275 Practice for Describing and Measuring Performance of
Ultraviolet and Visible Spectrophotometers
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions:
priate safety, health, and environmental practices and deter-
3.1.1 For definitions of terms used in these test methods,
mine the applicability of regulatory limitations prior to use.
refer to Terminology D1129.
For specific hazard statements, see 11.1 and 20.2.
3.2 Definitions of Terms Specific to This Standard:
1.5 This international standard was developed in accor-
3.2.1 total recoverable arsenic, n—a descriptive term relat-
dance with internationally recognized principles on standard-
ing to the arsenic forms recovered in the acid-digestion
ization established in the Decision on Principles for the
procedure specified in these test methods.
Development of International Standards, Guides and Recom-
3.2.1.1 Discussion—Some organic-arsenic compounds,
mendations issued by the World Trade Organization Technical
such as phenylarsonic acid, disodium methane arsonate, and
Barriers to Trade (TBT) Committee. dimethylarsonic acid, are not recovered completely during the
digestion step.
4. Significance and Use
These test methods are under the jurisdiction of ASTM Committee D19 on
4.1 Herbicides, insecticides, and many industrial effluents
Water and are the direct responsibility of Subcommittee D19.05 on Inorganic
contain arsenic and are potential sources of water pollution.
Constituents in Water.
Current edition approved Dec. 1, 2023. Published December 2023. Originally
Arsenic is significant because of its adverse physiological
approved in 1993. Last previous edition approved in 2015 as D2972 – 15. DOI:
effects on humans.
10.1520/D2972-15R23.
Similar to that appearing in Standard Methods for the Examination of Water
and Wastewater, 12th edition, APHA, Inc., New York, NY, 1965; and identical with For referenced ASTM standards, visit the ASTM website, www.astm.org, or
that in Brown, E., Skougstad, M. W., and Fishman, M. J., “Methods for Collection contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
and Analysis of Water Samples for Dissolved Minerals and Gases,” Techniques of Standards volume information, refer to the standard’s Document Summary page on
Water-Resources Investigations of the U.S. Geological Survey, Book 5, 1970, p. 46. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2972 − 15 (2023)
5. Purity of Reagents stannous chloride, and finally to gaseous arsine by zinc in
hydrochloric acid solution. The resulting mixture of gases is
5.1 Reagent grade chemicals shall be used in all tests.
passed through a scrubber containing borosilicate wool im-
Unless otherwise indicated, it is intended that all reagents shall
pregnated with lead acetate solution and then into an absorp-
conform to the specifications of the Committee on Analytical
tion tube containing a solution of silver diethyldithiocarbamate
Reagents of the American Chemical Society, where such
in pyridine. Arsine reacts with this reagent to form a red-
specifications are available. Other grades may be used, pro-
colored silver sol having maximum absorbance at about
vided it is first ascertained that the reagent is of sufficiently
540 nm. The absorbance of the solution is measured photo-
high purity to permit its use without lessening the accuracy of
metrically and the arsenic determined by reference to an
the determination.
analytical curve prepared from standards.
5.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean reagent water conforming
9. Interferences
to Specification D1193, Type I. Other reagent water types may
9.1 Although many samples are relatively free of
be used provided it is first ascertained that the water is of
interferences, several metals, notably cobalt, nickel, mercury,
sufficiently high purity to permit its use without adversely
silver, platinum, copper, chromium, and molybdenum, may
affecting the bias and precision of the test method. Type II
interfere with the evolution of arsine and with the recovery of
water was specified at the time of round robin testing of these
arsenic. The presence of any or all of these metals in a sample
test methods.
being analyzed must be considered as a potential source of
interference, and the analyst must fully determine the extent of
6. Sampling
actual interference, if any. This could be accomplished by
6.1 Collect the sample in accordance with Practices D3370.
spiking.
6.2 Preserve the samples with HNO (sp gr 1.42) to a pH of
9.2 Hydrogen sulfide and other sulfides interfere, but com-
2 or less immediately at the time of collection; normally about
monly encountered quantities are effectively removed by the
2 mL/L is required. If only dissolved arsenic is to be
lead acetate scrubber and the digestion.
determined, filter the sample through a 0.45 μm membrane
9.3 Antimony interferes by forming stibine, which distills
filter before acidification. The holding times for the samples
along with the arsine. Stibine reacts with the color-forming
may be calculated in accordance with Practice D4841.
reagent to form a somewhat similar red sol having maximum
NOTE 1—Alternatively, the pH may be adjusted in the laboratory if the
absorbance near 510 nm. The sensitivity for antimony at
sample is returned within 14 days. However, acid must be added at least
540 nm is only about 8 % that of arsenic (1 mg/L of antimony
24 h before analysis to dissolve any metals that adsorb to the container
will show an apparent presence of 0.08 mg/L of arsenic).
walls. This could reduce hazards of working with acids in the field when
appropriate.
9.4 Nitric acid interferes with the test and must be com-
pletely eliminated during the digestion.
TEST METHOD A—SILVER
DIETHYLDITHIOCARBAMATE COLORIMETRIC
10. Apparatus
7. Scope
10.1 Arsine Generator, Scrubber, and Absorber, assembled
7.1 This test method covers the determination of dissolved
as shown in Fig. 1.
and total recoverable arsenic in most waters and waste waters
10.2 Spectrophotometer or Filter Photometer, suitable for
in the range from 5 μg ⁄L to 250 μg ⁄L of arsenic.
use at 540 nm and providing a light path of at least 10 mm. The
7.2 The precision and bias data were obtained on reagent
filter photometer and photometric practice prescribed in this
water, river water, and process water. The information on
method shall conform to Practice E60. The spectrophotometer
precision and bias may not apply to other waters. It is the user’s
shall conform to Practice E275.
responsibility to ensure the validity of this test method for
waters of untested matrices.
11. Reagents and Materials
11.1 Arsenic Solution, Stock (1.00 mL = 1.00 mg As)—
8. Summary of Test Method
Commercially purchase or dissolve 1.320 g of arsenic trioxide
8.1 Organic arsenic-containing compounds are decomposed
(As O ) (Warning—Arsenic trioxide is extremely toxic. Avoid
2 3
by adding sulfuric and nitric acids and repeatedly evaporating
ingestion or inhalation of dry powder during standard prepa-
the sample to fumes of sulfur trioxide. The arsenic (V) so
ration. Wash hands thoroughly immediately after handling
produced, together with inorganic arsenic originally present, is
arsenic trioxide. Under no circumstances pipette any arsenic
subsequently reduced to arsenic (III) by potassium iodide and
solutions by mouth.), dried for at least 1 h at 110 °C, in 10 mL
of NaOH solution (420 g/L) and dilute to 1 L with water. This
solution is stable. A purchased arsenic stock solution of
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
appropriate known purity is acceptable.
Standard-Grade Reference Materials, American Chemical Society, Washington,
DC. For suggestions on the testing of reagents not listed by the American Chemical
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
copeial Convention, Inc. (USPC), Rockville, MD. Available commercially.
D2972 − 15 (2023)
11.9 Potassium Iodide Solution (150 g/L)—Dissolve 15 g of
potassium iodide (KI) in 100 mL of water. Store in an amber
bottle.
11.10 Silver Diethyldithiocarbamate Solution—Dissolve 1 g
of silver diethyldithiocarbamate (AgDDC) in 200 mL of
pyridine. This solution is stable for at least several months
when stored in an amber bottle.
11.11 Sodium Hydroxide Solution (420 g/L)—Dissolve 42 g
of sodium hydroxide (NaOH) pellets in 100 mL of water.
(Warning—This is a very exothermic reaction.)
11.12 Stannous Chloride Solution—Dissolve 40 g of
arsenic-free stannous chloride (SnCl ·2H O) in 100 mL of HCl
2 2
(sp gr 1.19). Add a few small pieces of mossy tin (which is the
common name and is commercially available).
11.13 Sulfuric Acid (1 + 1)—Cautiously, and with constant
stirring and cooling, add 250 mL of concentrated H SO (sp gr
2 4
1.84) to 250 mL of water.
11.14 Zinc, Granular, 20-mesh. Arsenic content must not
−6
exceed 1 × 10 %.
12. Standardization
12.1 Clean all glassware before use by rinsing first with hot
HNO (1 + 1) (11.7) and then with water. The absorbers must
be additionally rinsed with acetone and then air-dried.
12.2 Prepare, in a 250 mL generator flask, a blank and
sufficient standards containing from 0.0 μg to 25.0 μg of
arsenic by diluting 0.0 mL to 25.0 mL portions of the arsenic
standard solution to approximately 100 mL with water. Ana-
lyze at least five or more working standards containing
FIG. 1 Arsine Generator, Scrubber, and Absorber
concentrations of arsenic to define the nonlinear curve that
bracket the expected sample concentration, prior to analysis of
samples, to calibrate the instrument. A higher order of the curve
11.2 Arsenic Solution, Intermediate (1.00 mL = 10.0 μg
may be necessary.
As)—Dilute 5.00 mL of arsenic stock solution to 500 mL with
12.3 Proceed as directed in 13.3 – 13.9.
water.
12.4 Read directly the concentration or prepare an analytical
11.3 Arsenic Solution, Standard (1.00 mL = 1.00 μg As)—
curve by plotting the absorbances of standards versus micro-
Dilute 10.0 mL of arsenic intermediate solution to 100 mL with
grams of arsenic.
water. Prepare fresh before each use.
NOTE 2—The response is linear up to 15 μg of arsenic; however,
11.4 Filter Paper—Purchase suitable filter paper. Typically
because the curve is nonlinear above 15 μg, it is necessary to have
the filter papers have a pore size of 0.45 μm membrane.
sufficient standards above 15 μg to permit constructing an accurate curve.
Material such as fine-textured, acid-washed, ashless paper, or
glass fiber paper are acceptable. The user must first ascertain
13. Procedure
that the filter paper is of sufficient purity to use without
13.1 Clean all glassware before use by rinsing first with hot
adversely affecting the bias and precision of the test method.
HNO (1 + 1) (11.8) and then with water. The absorbers must
11.5 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
be additionally rinsed with acetone and then air-dried.
chloric acid (HCl). Use analytical grade acid with an arsenic
13.2 Pipette a volume of well-mixed acidified sample con-
−6
content not greater than 1 × 10 %.
taining less than 25 μg of arsenic (100 mL maximum) into a
11.6 Lead Acetate Solution (100 g/L)—Dissolve 10 g of lead
generating flask and dilute to approximately 100 mL.
acetate (Pb(C H O ) ·3H O) in 100 mL of water. Store reagent
2 3 2 2 2
NOTE 3—If only dissolved arsenic is to be determined use a filtered
in a tightly stoppered container.
(11.4) and acidified sample (see 6.2).
11.7 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
13.3 To each flask, add 7 mL of H SO (1 + 1) (11.13) and
2 4
(HNO ). Use analytical grade acid with an arsenic content not
5 mL of concentrated HNO (11.7) (sp gr 1.42). Add a small
−6
greater than 1 × 10 %.
boiling chip and carefully evaporate to dense fumes of SO ,
11.8 Nitric Acid (1 + 1)—Add 250 mL of concentrated nitric maintaining an excess of HNO until all organic matter is
acid (sp gr 1.42) to 250 mL of water. destroyed. This prevents darkening of the solution and possible
D2972 − 15 (2023)
TABLE 1 Precision and Bias for Arsenic by Test Method A,
reduction and loss of arsenic. Cool, add 25 mL of water, and
Diethyldithiocarbamate Colorimetric
again evaporate to dense fumes of SO . Maintain heating for
Amount Amount
15 min to expel oxides of nitrogen.
Water Added, Found, S S Bias, %
t o
μg/L μg/L
13.4 Cool, and adjust the volume in each flask to approxi-
mately 100 mL with water. Reagent Type II 25.0 23.66 1.76 1.78 −5.4
100.0 95.28 5.21 5.24 −4.7
13.5 To each flask add successively, with thorough mixing
200.0 194.99 8.43 8.79 −2.6
Water of Choice 25.0 24.76 2.07 1.84 −0.96
after each addition, 8 mL of concentrated HCl (11.5) (sp gr
100.0 97.00 4.15 3.78 −3.0
1.19), 4 mL of KI solution (11.9), and 1 mL of SnCl solution
200.0 189.01 9.96 9.70 −5.5
(11.12). Allow about 15 min for complete reduction of the
arsenic to the trivalent state.
13.6 Place in each scrubber a plug of borosilicate wool that
15.4 Three independent laboratories participated in the
has been impregnated with lead acetate solution. Assemble the round robin study. Precision and bias for this test method
generator, scrubber, and absorber, making certain that all parts
conform to Practice D2777 – 77, which was in place at the time
fit and are correctly adjusted. Add 3.00 mL of silver
of collaborative testing. Under the allowances made in 1.4 of
diethyldithiocarbamate-pyridine solution (11.10) to each ab- Practice D2777 – 13, these precision and bias data do meet
sorber. Add glass beads to the absorbers until the liquid just
existing requirements for interlaboratory studies of Committee
covers them. D19 test methods.
NOTE 4—Four millilitres of silver diethyldithiocarbamate-pyridine
16. Quality Control
solution may be used with some loss of sensitivity.
16.1 In order to be certain that analytical values obtained
13.7 Disconnect each generator, add 6 g of zinc (11.14), and
using these test methods are valid and accurate within the
reconnect immediately.
confidence limits of the test, the following QC procedures must
13.8 Allow 30 min for complete evolution of arsine. Warm
be followed when analyzing arsenic.
the generator flasks for a few minutes to make sure that all
16.2 Calibration and Calibration Verification:
arsine is released.
16.2.1 Analyze at least five or more working standards
13.9 Pour the solutions from the absorbers directly into
containing concentrations of arsenic that bracket the expected
clean spectrophotometer cells and within 30 minutes measure
sample concentration, prior to analysis of samples, to calibrate
the absorbance of each at 540 nm.
the instrument (see 12.2). The calibration correlation coeffi-
cient shall be equal to or greater than 0.990.
14. Calculation
16.2.2 Verify instrument calibration after standardization by
14.1 Determine the weight of arsenic in each sample by
analyzing a standard at the concentration of one of the
referring to the analytical curve. Calculate the concentration of
calibration standards. The concentration of a mid-range stan-
arsenic in the sample in micrograms per litre, using Eq 1:
dard should fall within 615 % of the known concentration.
Analyze a calibration blank to verify cleanliness.
Arsenic, µg/L 5 1000 W/V (1)
16.2.3 If calibration cannot be verified, recalibrate the
where:
instrument.
1000 = 1000 mL/L,
16.2.4 It is recommended to analyze a continuing calibra-
V = volume of sample, mL, and
tion blank (CCB) and continuing calibration verification
W = weight of arsenic in sample, μg.
(CCV) at a 10 % frequency. The results should fall within the
6 expected precision of the method or 615 % of the known
15. Precision and Bias
concentration.
15.1 The single-operator and overall precision of this
16.3 Initial Demonstration of Laboratory Capability:
method for three laboratories, which included a total of six
16.3.1 If a laboratory has not performed the test before, or if
operators analyzing each sample on three different days, within
there has been a major change in the measurement system, for
its designated range varies with the quantity being tested in
example, new analyst, new instrument, etc., a precision and
accordance with Table 1.
bias study must be performed to demonstrate laboratory
15.2 Recoveries of known amounts of arsenic (arsenic
capability.
trioxide) in a series of prepared standards are given in Table 1.
16.3.2 Analyze seven replicates of a standard solution
prepared from an Independent Reference Material containing a
15.3 The precision and bias data were obtained on reagent
mid-range concentration of arsenic. The matrix and chemistry
water, river water, and process water. The information on
of the solution should be equivalent to the solution used in the
precision and bias may not apply to other waters. It is the user’s
collaborative study. Each replicate must be taken through the
responsibility to ensure the validity of this test method for
complete analytical test method including any sample preser-
waters of untested matrices.
vation and pretreatment steps.
16.3.3 Calculate the mean and standard deviation of the
Supporting data have been filed at ASTM International Headquarters and may
seven values and compare to the acceptable ranges of bias in
be obtained by requesting Research Report RR:D19-1049. Contact ASTM Customer
Service at [e-mail]. Table 1. This study should be repeated until the recoveries are
D2972 − 15 (2023)
within the limits given in Table 1. If a concentration other than Guide D5810, Table 1. If the percent recovery is not within
the recommended concentration is used, refer to Practice these limits, a matrix interference may be present in the sample
D5847 for information on applying the F test and t test in selected for spiking. Under these circumstances, one of the
evaluating the acceptability of the mean and standard devia- following remedies must be employed: the matrix interference
tion. must be removed, all samples in the batch must be analyzed by
a test method not affected by the matrix interference, or the
16.4 Laboratory Control Sample (LCS):
results must be qualified with an indication that they do not fall
16.4.1 To ensure that the test method is in control, prepare
within the performance criteria of the test method.
and analyze a LCS containing a known concentration of
NOTE 5—Acceptable spike recoveries are dependent on the known
arsenic with each batch (laboratory defined or twenty samples).
concentration of the component of interest. See Guide D5810 for
If large numbers of samples are analyzed in the batch, analyze
additional information.
the LCS after every 10 samples. The laboratory control
16.7 Duplicate:
samples for a large batch should cover the analytical range
16.7.1 To check the precision of sample analyses, analyze a
when possible. The LCS must be taken through all of the steps
sample in duplicate with each laboratory-defined batch. If the
of the analytical method including sample preservation and
known concentration of the analyte is less than five times the
pretreatment. The result obtained for a mid-range LCS shall
detection limit for the analyte, a matrix spike duplicate (MSD)
fall within 615 % of the known concentration.
should be used.
16.4.2 If the result is not within these limits, analysis of
16.7.2 Calculate the standard deviation of the duplicate
samples is halted until the problem is corrected, and either all
values and compare to the precision in the collaborative study
the samples in the batch must be reanalyzed, or the results must
using an F test. Refer to 6.4.4 of Practice D5847 for informa-
be qualified with an indication that they do not fall within the
tion on applying the F test.
performance criteria of the test method.
16.7.3 If the result exceeds the precision limit, the batch
16.5 Method Blank:
must be reanalyzed or the results must be qualified with an
16.5.1 Analyze a reagent water test blank with each
indication that they do not fall within the performance criteria
laboratory-defined batch. The known concentration of arsenic
of the test method.
found in the blank should be less than 0.5 times the lowest
16.8 Independent Reference Material (IRM):
calibration standard. If the known concentration of arsenic is
16.8.1 In order to verify the quantitative value produced by
found above this level, analysis of samples is halted until the
the test method, analyze an Independent Reference Material
contamination is eliminated, and a blank shows no contamina-
(IRM) submitted as a regular sample (if practical) to the
tion at or above this level, or the results must be qualified with
laboratory at least once per quarter. The known concentration
an indication that they do not fall within the performance
of the IRM should be in the known concentration mid-range for
criteria of the test method.
the method chosen. The value obtained must fall within the
16.6 Matrix Spike (MS):
control limits established by the laboratory.
16.6.1 To check for interferences in the specific matrix
TEST METHOD B—ATOMIC ABSORPTION,
being tested, perform a MS on at least one sample from each
HYDRIDE GENERATION
laboratory-defined batch by spiking an aliquot of the sample
with a known concentration of arsenic and taking it through the
17. Scope
analytical method.
17.1 This test method covers the determination of dissolved
16.6.2 The spike known concentration plus the background
and total recoverable arsenic in most waters and wastewaters in
known concentration of arsenic must not exceed the high
the range from 1 μg ⁄L to 20 μg ⁄L of arsenic. The range may be
calibration standard. The spike must produce a known concen-
extended by dilution of the sample.
tration in the spiked sample that is 2 to 5 times the analyte
known concentration in the unspiked sample, or 10 to 50 times
17.2 The precision and bias data were obtained on reagent
the detection limit of the test method, whichever is greater.
water, tap water, salt water, river water, and untreated waste-
16.6.3 Calculate the percent recovery of the spike (P) using
water. The information on precision and bias may not apply to
the following equation:
other waters. It is the user’s responsibility to ensure the validity
of this test method for waters of untested matrices.
P 5 100 @A~V 1V! 2 B V #/C V (2)
s s
where: 18. Summary of Test Method
A = analyte known concentration (μg/L) in spiked sample,
18.1 Organic arsenic-containing compounds are decom-
B = analyte known concentration (μg/L) in unspiked
posed by adding sulfuric and nitric acids and repeatedly
sample,
evaporating the sample to fumes of sulfur trioxide. The arsenic
C = known concentration (μg/L) of analyte in spiking
(V) so produced, together with inorganic arsenic originally
solution,
present, is subsequently reduced to arsenic (III) by potassium
V = volume (mL) of sample used, and
s
iodide and stannous chloride, and finally to gaseous arsine by
V = volume (mL) of spiking solution added.
zinc in hydrochloric acid solution. Alternatively, the arsenic is
16.6.4 The percent recovery of the spike shall fall within the converted to arsine by sodium borohydride in hydrochloric
limits, based on the analyte known concentration, listed in acid solution. The arsine is removed from solution by aeration
D2972 − 15 (2023)
and swept by a flow of nitrogen into a hydrogen flame where 21.6 Nitric Acid (sp gr 1.42)—See 11.7.
it is determined by atomic absorption at 193.7 nm.
21.7 Nitric Acid (1 + 1)—See 11.8.
19. Interferences 21.8 Nitric Acid (1 + 4)—Add 20 mL of nitric acid (sp gr
1.42) to 80 mL of water.
19.1 See 9.1.
21.9 Potassium Iodide Solution (150 g/L)—See 11.9.
20. Apparatus
21.10 Sodium Borohydride Solution (4 g/100 mL)—
20.1 Arsine Vapor Analyzer, assembled as shown in Fig. 2.
Dissolve 4 g of sodium borohydride (NaBH ) in 100 mL of
water. Prepare fresh before each use.
20.2 Atomic Absorption Spectrophotometer (Warning—
Because of the toxicity of arsenic, a well-ventilated hood must
21.11 Stannous Chloride Solution (400 g/L)—See 11.12.
be used with the atomic absorption spectrometer.) for use at
21.12 Sulfuric Acid (1 + 1)—See 11.13.
193.7 nm.
21.13 Zinc Metal (Dust) Suspension—Add 10 g of zinc dust
NOTE 6—Follow the manufacturer’s instructions for all instrumental
to 20 mL of water.
parameters.
21.14 Hydrogen—Set burner control box to a gauge pres-
20.2.1 Arsenic Light Source—Arsenic electrodeless dis-
sure of 55 kPa (8 psi) and adjust the flowmeter to approxi-
charge lamp or hollow-cathode lamp.
mately 6 L/min.
21. Reagents and Materials
21.15 Nitrogen or Argon—Set burner control box to a gauge
21.1 Arsenic Solution, Stock (1.00 mL = 1.00 mg As)—See
pressure of 207 kPa (30 psi) and adjust the flowmeter for
11.1.
maximum sensitivity by volatilizing standards. A flow of
approximately 8 L/min has been found satisfactory for this
21.2 Arsenic Solution, Intermediate (1.00 mL = 10.0 μg
purpose. This will depend on the burner used.
As)—See 11.2.
21.3 Arsenic Solution, Standard (1.00 mL = 0.10 μg As)— 22. Standardization
Dilute 10.0 mL of arsenic intermediate solution to 1000 mL
22.1 Clean all glassware before use by rinsing first with hot
with water. Prepare fresh before each use.
HNO (1 + 1) and then with water.
21.4 Filter Paper—See 11.4.
22.2 Prepare, in 200 mL Berzelius beakers or similar
21.5 Hydrochloric Acid (sp gr 1.19)—See 11.5. apparatus, a blank and sufficient standards containing from
0.0 μg to 1.0 μg of arsenic by diluting 0.0 mL to 10.0 mL
portions of the arsenic standard solution to approximately
A static system, such as one using a balloon, has been found satisfactory for this
50 mL. Analyze at least three working standards containing
purpose. See McFarren, E. F., “New Simplified Methods for Metal Analysis,”
known concentrations of arsenic that bracket the expected
Journal of American Water Works Association, Vol 64, 1972, p. 28.
NOTE 1—Fleaker, trademarked product of Corning Glass Works, and Berzelius beaker are available from most laboratory apparatus dealers.
FIG. 2 Arsine Vapor Analyzer
D2972 − 15 (2023)
sample known concentration, prior to analysis of samples, to maintaining an excess of HNO until all organic matter is
calibrate the instrument. destroyed. This prevents darkening of the solution and possible
reduction and loss of arsenic. Cool, add 25 mL of water, and
22.3 Proceed as directed in 23.1.3 – 23.1.8 or 23.2.3 –
again evaporate to f
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