ASTM D1687-17

Standard Test Methods for Chromium in Water

SIGNIFICANCE AND USE
4.1 Hexavalent chromium salts are used extensively in metal finishing and plating applications, in anodizing aluminum, and in the manufacture of paints, dyes, explosives, and ceramics. Trivalent chromium salts are used as mordants in textile dyeing, in the ceramic and glass industry, in the leather industry as a tanning agent, and in photography. Chromium may be present in wastewater from these industries and may also be discharged from chromate-treated cooling waters.  
4.2 The hexavalent state of chromium is toxic to humans, animals, and aquatic life. It can produce lung tumors when inhaled and readily induces skin sensitization.
SCOPE
1.1 These test methods cover the determination of hexavalent and total chromium in water. Section 34 on Quality Control pertains to these test methods. Three test methods are included as follows:    
Test Method  
Concentration
Range  
Sections  
A—Photometric Diphenyl-
carbohydrazide  
0.01 to 0.5 mg/L  
7 – 15  
B—Atomic Absorption,
Direct  
0.1 to 10 mg/L  
16 – 24  
C—Atomic Absorption, Graphite
Furnace  
5 to 100 μg/L  
25 – 33  
1.2 Test Method A is a photometric method that measures dissolved hexavalent chromium only. Hexavalent chromium can also be determined by ion chromatography, see Test Method D5257. Test Methods B and C are atomic absorption methods that are generally applicable to the determination of dissolved or total recoverable chromium in water without regard to valence state. ICP-MS or ICP-AES may also be appropriate but at a higher instrument cost. See Test Methods D5673 and D1976.  
1.3 Test Method A has been used successfully with reagent grade water Types I, II, and III, tap water, 10 % NaCl solution, treated water from a synthetic organic industrial plant that meets National Pollution Discharge Elimination System (NPDES) permit requirements, and EPA-extraction procedure leachate water, process water, lake water, effluent treatment, that is, lime neutralization and precipitation of spent pickle liquor and associated rinse water from stainless steel pickling. Test Method C has been used successfully with reagent water, stock scrubber water, lake water, filtered tap water, river water, well water, production plant water, and a condensate from a medium BTU coal gasification process. Matrices used, except for reagent water, are not available for Test Method B. It is the user's responsibility to ensure the validity of these test methods for waters of untested 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 4.2, 20.3, and 20.8.1.  
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

• Replaces: ASTM D1687-12 - Standard Test Methods for Chromium 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 D5257-17 - Standard Test Method for Dissolved Hexavalent Chromium in Water by Ion Chromatography
• Effective Date: 01-Dec-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 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

Overview

ASTM D1687-17: Standard Test Methods for Chromium in Water is a comprehensive standard developed by ASTM International for the reliable determination of both hexavalent and total chromium in water. Addressing industrial and environmental needs, this standard provides methodologies for accurately assessing chromium concentrations in diverse water matrices and is vital for compliance with environmental regulations and for quality control in industries that use or discharge chromium compounds.

Chromium, particularly in its hexavalent form, is widely used in metal finishing, plating, anodizing, ceramics, paints, dyes, and other manufacturing processes. Owing to its toxicity, especially in the hexavalent state, regular monitoring of chromium levels in wastewater and environmental water sources is essential to safeguard human health and aquatic life.

Key Topics

• Hexavalent & Total Chromium Measurement: The standard outlines test methods for both dissolved hexavalent chromium and total (all valence states) chromium in water.
• Three Analytical Methods:
  • Photometric Diphenylcarbazide Method: For dissolved hexavalent chromium (range: 0.01–0.5 mg/L).
  • Atomic Absorption, Direct Method: For dissolved/total chromium (range: 0.1–10 mg/L).
  • Atomic Absorption, Graphite Furnace Method: For low-level chromium (range: 5–100 μg/L).
• Applicable Water Matrices: Details use in reagent water, tap water, industrial effluents, environmental samples, and various process waters.
• Sample Preservation and Handling: Recommendations for proper collection, preservation, and storage to avoid contamination or chromium loss.
• Precautions and Quality Control: Emphasizes user responsibility in following safety protocols, adhering to quality assurance practices, and verifying applicability for new matrices.
• Regulatory Compliance: Supports consistency in measurement required by environmental permits (e.g., NPDES).

Applications

• Environmental Monitoring & Compliance: Assists industries and laboratories in monitoring chromium discharge to comply with regulatory standards and environmental protection requirements.
• Industrial Process Water Control: Essential for industries such as metal plating, dye manufacturing, ceramics, leather, and textile processing, where chromium is used and may be found in wastewater.
• Public Health Safeguarding: Enables public utilities and agencies to detect and monitor chromium contamination in drinking and surface waters, reducing risks to human health from toxic hexavalent chromium.
• Research and Method Validation: Widely referenced for environmental and toxicology studies requiring standardized, validated chromium analysis in water.

Related Standards

• ASTM D5257: Test Method for Dissolved Hexavalent Chromium in Water by Ion Chromatography
• 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 ICP Atomic Emission Spectroscopy (ICP-AES)
• ASTM D858/D1068/D1688/D1691: Methods for manganese, iron, copper, and zinc in water
• ASTM D1129/D1193: Terminology and specifications for water quality and reagent water types
• ASTM D2777: Guide for demonstration of method precision and bias

Practical Value

Implementing ASTM D1687-17 ensures reliable, reproducible chromium detection in water across various industries, facilitating environmental stewardship, regulatory compliance, and protection of public health. These standardized methods serve as a benchmark for laboratories and industries globally where trace metals determination is critical. Integrating these methods into routine water monitoring supports best practices for analytics, risk management, and environmental responsibility.

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Keywords: ASTM D1687, chromium in water, hexavalent chromium, total chromium, water quality testing, environmental compliance, atomic absorption, photometric method, wastewater monitoring, industrial effluent, water analysis standards.

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: D1687 − 17
Standard Test Methods for
Chromium in Water
This standard is issued under the fixed designation D1687; 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* 1.4 The values stated in SI units are to be regarded as
standard. The values given in parentheses are mathematical
1.1 These test methods cover the determination of hexava-
conversion to inch-pound units that are provided for informa-
lent and total chromium in water. Section 34 on Quality
tion only and are not considered standard.
Control pertains to these test methods. Three test methods are
1.5 This standard does not purport to address all of the
included as follows:
safety concerns, if any, associated with its use. It is the
Concentration
Test Method Sections
Range responsibility of the user of this standard to establish appro-
A—Photometric Diphenyl- 0.01 to 0.5 mg/L 7–15
priate safety and health practices and determine the applica-
carbohydrazide
bility of regulatory limitations prior to use. For specific hazard
B—Atomic Absorption, 0.1to10mg/L 16–24
Direct statements, see 4.2, 20.3, and 20.8.1.
C—Atomic Absorption, Graphite 5 to 100 µg/L 25–33
1.6 This international standard was developed in accor-
Furnace
dance with internationally recognized principles on standard-
1.2 Test Method A is a photometric method that measures
ization established in the Decision on Principles for the
dissolved hexavalent chromium only. Hexavalent chromium
Development of International Standards, Guides and Recom-
can also be determined by ion chromatography, see Test
mendations issued by the World Trade Organization Technical
Method D5257. Test Methods B and C are atomic absorption
Barriers to Trade (TBT) Committee.
methods that are generally applicable to the determination of
dissolved or total recoverable chromium in water without
2. Referenced Documents
regard to valence state. ICP-MS or ICP-AES may also be
2.1 ASTM Standards:
appropriate but at a higher instrument cost. See Test Methods
D858 Test Methods for Manganese in Water
D5673 and D1976.
D1066 Practice for Sampling Steam
1.3 Test Method A has been used successfully with reagent
D1068 Test Methods for Iron in Water
grade water Types I, II, and III, tap water, 10 % NaCl solution,
D1129 Terminology Relating to Water
treated water from a synthetic organic industrial plant that
D1193 Specification for Reagent Water
meets National Pollution Discharge Elimination System
D1688 Test Methods for Copper in Water
(NPDES) permit requirements, and EPA-extraction procedure
D1691 Test Methods for Zinc in Water
leachate water, process water, lake water, effluent treatment,
D1886 Test Methods for Nickel in Water
that is, lime neutralization and precipitation of spent pickle
D1976 Test Method for Elements in Water by Inductively-
liquor and associated rinse water from stainless steel pickling.
Coupled Argon Plasma Atomic Emission Spectroscopy
Test Method C has been used successfully with reagent water,
D2777 Practice for Determination of Precision and Bias of
stock scrubber water, lake water, filtered tap water, river water,
Applicable Test Methods of Committee D19 on Water
well water, production plant water, and a condensate from a
D3370 Practices for Sampling Water from Closed Conduits
medium BTU coal gasification process. Matrices used, except
D3557 Test Methods for Cadmium in Water
for reagent water, are not available for Test Method B. It is the
D3558 Test Methods for Cobalt in Water
user’sresponsibilitytoensurethevalidityofthesetestmethods
D3559 Test Methods for Lead in Water
for waters of untested matrices.
D3919 Practice for Measuring Trace Elements in Water by
Graphite Furnace Atomic Absorption Spectrophotometry
These test methods are under the jurisdiction of ASTM Committee D19 on
Water and are the direct responsibility of Subcommittee D19.05 on Inorganic
Constituents in Water. 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 D1687 – 12. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D1687-17. 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
D1687 − 17
D4691 Practice for Measuring Elements in Water by Flame Reagents of the American Chemical Society where such
Atomic Absorption Spectrophotometry specifications are available. Other grades may be used, pro-
D4841 Practice for Estimation of Holding Time for Water
vided it is first ascertained that the reagent is of sufficiently
Samples Containing Organic and Inorganic Constituents
high purity to permit its use without lessening the accuracy of
D5257 Test Method for Dissolved Hexavalent Chromium in
the determination.
Water by Ion Chromatography
5.2 Purity of Water—Unless otherwise indicated, references
D5673 Test Method for Elements in Water by Inductively
towatershallbeunderstoodtomeanreagentwaterconforming
Coupled Plasma—Mass Spectrometry
to Specification D1193, Type I, II, or III water. Type I is
D5810 Guide for Spiking into Aqueous Samples
preferred and more commonly used. Type II water was
D5847 Practice for Writing Quality Control Specifications
specified at the time of round robin testing of these test
for Standard Test Methods for Water Analysis
methods.
E60 Practice for Analysis of Metals, Ores, and Related
Materials by Spectrophotometry
NOTE 1—The user must ensure the type of reagent water chosen is
E275 Practice for Describing and Measuring Performance of
sufficiently free of interferences. The water should be analyzed using the
Ultraviolet and Visible Spectrophotometers
test method.
3. Terminology
6. Sampling
3.1 Definitions:
6.1 Collect the sample in accordance with the applicable
3.1.1 For definitions of terms used in this standard, refer to
ASTM standard as follows: Practice D1066, or Practices
Terminology D1129.
D3370. The holding time for the samples may be calculated in
3.2 Definitions of Terms Specific to This Standard: accordance with Practice D4841.
3.2.1 continuing calibration blank, n—a solution containing
6.2 Samples to be analyzed by Test Method A should be
no analytes (of interest) which is used to verify blank response
stabilized upon collection by addition of sodium hydroxide
and freedom from carryover.
solution to a pH greater than or equal to 8, or analyzed
3.2.2 continuing calibration verification, n—a solution (or
immediately. Minor delays in stabilization or analyses of
setofsolutions)ofknownconcentrationusedtoverifyfreedom
samples containing sulfur reduction compounds can produce
from excessive instrumental drift; the concentration is to cover
significant loss in hexavalent chromium. Acidic samples con-
the range of calibration curve.
taining hypobromite, persulfate, or chlorine could oxidize
trivalent chromium, if present, to hexavalent form upon
3.2.3 laboratory control sample, n—a solution with the
preservation, resulting in a positive interference. When the
certified concentration(s) of the analytes.
presence of these oxidizing compounds is suspected, samples
3.2.4 total recoverable chromium, n—a descriptive term
should not be preserved but analyzed immediately. It will be
relating to the forms of chromium recovered in the acid-
evident that in this case, the simultaneous presence of reducing
digestion procedure specified in this test standard.
compounds could not be anticipated.
4. Significance and Use 6.3 Samples to be analyzed by Test Methods B and C shall
be preserved by addition of HNO (sp gr 1.42) to pH of 2 or
4.1 Hexavalent chromium salts are used extensively in
lessimmediatelyatthetimeofcollection,normallyabout2mL
metal finishing and plating applications, in anodizing
HNO /L. If only dissolved chromium is to be determined, the
aluminum, and in the manufacture of paints, dyes, explosives,
sample shall be filtered through a 0.45-µm membrane filter
andceramics.Trivalentchromiumsaltsareusedasmordantsin
(11.8) before acidification.
textile dyeing, in the ceramic and glass industry, in the leather
industry as a tanning agent, and in photography. Chromium
NOTE 2—Alternatively, the pH may be adjusted in the laboratory within
may be present in wastewater from these industries and may
14 days of collection. However, acid must be added at least 24 hours
also be discharged from chromate-treated cooling waters. before analysis to dissolve any metals that adsorb to the container walls.
This could reduce hazards of working with acids in the field when
4.2 The hexavalent state of chromium is toxic to humans,
appropriate
animals, and aquatic life. It can produce lung tumors when
inhaled and readily induces skin sensitization.
Reagent Chemicals, American Chemical Society Specifications , American
5. Purity of Reagents
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
5.1 Reagent grade chemicals shall be used in all tests.
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Unless otherwise indicated, it is intended that all reagents shall
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
conform to the specifications of the Committee on Analytical MD.
D1687 − 17
TEST METHOD A—PHOTOMETRIC minimum path length of 10 mm. The photometers and photo-
DIPHENYLCARBOHYDRAZIDE metric practice prescribed in this test method shall conform to
Practice E60. Spectrophotometers and spectrophotometric
7. Scope
practice shall conform to Practice E275.
7.1 This test method covers the determination of dissolved
11. Reagents and Materials
hexavalent chromium in water.
11.1 Chromium Solution, Stock (1 mL = 0.10 mg Cr)—
7.2 The test method is applicable in the range from 0.01 to
Dissolve 0.2828 g of potassium dichromate (K Cr O that has
0.5 mg/L chromium. The range may be extended by appropri-
2 2 7
been oven dried at 105°C for 1 h) in water. Dilute to 1 L with
ate sample dilution.
water.Alternatively, certified stock solutions are commercially
7.3 This test method has been used successfully with
available through chemical supply vendors and may be used.
reagent grade water Types I, II, and III, tap water, 10 % NaCl
11.2 Chromium Solution, Standard (1 mL = 0.001 mg Cr)—
solution, treated water from a synthetic organic industrial plant
Dilute 10.0 mL of chromium stock solution (see 11.1)to1L
that meets NPDES permit requirements, EPA-extraction pro-
with water.
cedure leachate water, process water, lake water, effluent from
treatment that is, lime neutralization and precipitation of spent
11.3 Diphenylcarbazide Indicator Solution—Dissolve 0.25
pickle liquor and associated rinse water from stainless steel
g of powdered 1,5-diphenylcarbohydrazide in 100 mL of
pickling. It is the responsibility of the user to ensure the
acetone. Store in an amber glass-stoppered flask at 4°C when
validity of the test method to waters of untested matrices.
notinuse.Thissolutionisstableforaboutoneweekwhenkept
refrigerated. Prepare fresh reagent when the solution becomes
8. Summary of Test Method
discolored.
8.1 Hexavalent chromium reacts with 1.5-
NOTE 3—Allow the indicator solution to warm to room temperature
diphenylcarbohydrazide (s-diphenylcarbazide) in an acid me-
before use.
dium to produce a reddish-purple color. The intensity of the
11.4 Phosphoric Acid (1+1)—Dilute 500 mL of concen-
color formed is proportional to the hexavalent chromium
trated phosphoric acid (sp gr 1.69) to 1 L with water.
concentration.
11.5 Phosphoric Acid (1 + 19)—Dilute 50 mL of concen-
9. Interferences
trated phosphoric acid (sp gr 1.69) to 1 L with water.
9.1 Vanadium, titanium, or iron present at concentrations of
11.6 Sodium Hydroxide Solution (40 mg/L)—Dissolve 40
5 mg/Lyield a 10 to 30 % reduction in recovery of chromium.
mg of sodium hydroxide (NaOH) in water. Cool and dilute to
Copper at 100 mg/L yields a 20 to 30 % reduction in recovery
1 L. This solution is used for sample preservation.
in the presence of sulfate. Mercury gives a blue-purple color,
11.7 Sulfamic Acid(NH SO H)—Crystals.
2 3
butthereactionisnotverysensitiveatthepHemployedforthe
test. 11.8 Filter Paper—Purchase suitable filter paper. Typically
the filter papers have a pore size of 0.45-µm membrane.
9.2 Nitriteconcentrationsinexcessof10mg/LasNO yield
Material such as fine-textured, acid-washed, ashless paper, or
low test results. Sulfamic acid may be added (;10.1 g) prior to
glass fiber paper are acceptable. The user must first ascertain
the addition of diphenylcarbazide solution to minimize nitrite
that the filter paper is of sufficient purity to use without
interference. Add sulfamic acid only when the presence of
adversely affecting the bias and precision of the test method.
nitrite has been positively established. Excess sulfamic acid
itself creates a slightly positive interference.
12. Calibration
9.3 Sulfide and sulfite reduce chromate in an acid medium
12.1 Prepare a series of at least four standard solutions
to give low results.
containing from 0 to 0.50 mg/L of chromium by diluting
9.4 Several sample matrices have been identified which
measured volumes of the standard chromium solution (see
produce a yellow-orange complex that interferes with this
11.2) to 100 mL with water in separate volumetric flasks.
quantification. When this occurs, it may be remedied by
12.2 Transfer 50 mL of each prepared standard solution to
inverting the indicator-buffer sequence. In these cases the
separate 125-mL Erlenmeyer flasks and proceed with 13.3 –
analyst should evaluate the matrix effect with the additions of
13.6.
spikes (Guide D5810).
12.3 Prepare a calibration curve by plotting milligrams per
9.5 Although each interferent has been reported, most of the
liter of chromium versus absorbance on linear graph paper.
common interferences are eliminated by the preservation
procedure at the time of collection. The potentially interfering
12.4 Read directly in concentration if this capability is
metals are precipitated and the reducing effect of sulfur
provided with the instrument or prepare a calibration curve for
compounds has been overcome.
each photometer. A recalibration must be made if any altera-
tions of the instrument are made or if new reagents are
10. Apparatus
prepared. At the least, a blank and three chromium standard
10.1 Photometer—Spectrophotometer or filter photometer solutionsmustbeanalyzedtoverifytheoriginaltestcalibration
suitable for use at 540 nm and equipped with a cell having a each time the test is performed.
D1687 − 17
TABLE 1 Determination of Bias and Precision, Photometric Diphenylcarbohydrazide
Amount Mean Statistically
Added, Recovery ± Bias ± % Bias Significant S S
T 0
¯
mg/L (X), mg/L at 5 % Level
Reagent water:
0.010 0.0125 +0.0025 +25.0 yes 0.006 0.0031
0.050 0.0502 +0.0002 +0.40 no 0.007 0.0053
0.350 0.3484 −0.0016 −0.46 no 0.022 0.0130
0.500 0.4964 −0.0036 −0.72 no 0.022 0.0139
Water of choice:
0.010 0.0112 +0.0012 +12.0 no 0.005 0.0025
0.050 0.0468 −0.0032 −6.40 yes 0.007 0.0042
0.350 0.3378 −0.0122 −3.49 yes 0.026 0.0159
0.500 0.4776 −0.0224 −4.48 yes 0.038 0.0204
Leachate:
0.010 0.0148 +0.0048 +48.0 yes 0.008 0.0037
0.050 0.0513 +0.0013 +2.60 no 0.009 0.0062
0.350 0.3422 −0.0078 −2.23 yes 0.015 0.0093
0.500 0.4887 −0.0113 −2.26 yes 0.025 0.0130
13. Procedure leachate water, process water, lake water, effluent from
treatment, that is, lime neutralization and precipitation of spent
13.1 Filter a portion of the sample through a 0.45-µm
pickle liquor and associated rinse water from stainless steel
membrane filter (11.8) and adjust the pH into the 8 to 8.5 range
pickling.
if it is greater than 8.5 with a few drops of the phosphoric acid
15.2 Single-operator and overall precision of this test
solution (1 + 19).
method within its designated range and recovery data for the
13.2 Transfer 50.0 mL of the filtered sample, or a smaller
above waters for 16 laboratories, which include a total of 16
aliquot of sample diluted to 50.0 mL, to a 125-mLErlenmeyer
operators analyzing each sample on three different days, is
flask.
given in Table 1.
13.3 Add 2.0 mL of the diphenylcarbazide solution to each
15.3 Single-operator and overall precision of this test
solution and swirl to mix.
method within its designated range and recovery data for a
NOTE 4—If the sample is colored, prepare a separate aliquot as prepared leachate water for 8 laboratories, which include a
described in 13.1 and 13.2. Add 2.0 mL of acetone instead of diphenyl-
total of 8 operators analyzing each sample on three different
carbazidesolutionandproceedwith13.4and13.5.Usethissolutionasthe
days, is also given in Table 1.
sample blank.
15.4 It is the user’s responsibility to ensure the validity of
13.4 Immediately add 5.0 mL of phosphoric acid solution
the test method for waters of untested matrices.
(1 + 1) to each solution and swirl to mix.
15.5 Precision and bias for this test method conforms to
13.5 Permit the solutions to stand 15 min for full color
Practice D2777 – 77, which was in place at the time of
development. Measure the absorbance within 30 min after the
collaborative testing. Under the allowances made in 1.4 of
addition of the diphenylcarbazide solution at 540 nm with a
Practice D2777 – 13, these precision and bias data do meet
cell having a minimum path length of 10 mm.
existing requirements for interlaboratory studies of Committee
+6
13.6 Determine milligrams per liter of chromium as Cr in
D19 test methods.
the test sample by referring the direct instrument reading or the
TEST METHOD B—ATOMIC
absorbance to the prepared calibration curve (see 12.3).
ABSORPTION, DIRECT
14. Calculation
16. Scope
14.1 Calculate the hexavalent chromium concentration as
16.1 This test method covers the determination of dissolved
follows:
and total recoverable chromium in most waters, wastewaters,
Cr , mg/L 5 ~W 2 W !~50/S! (1)
S B
and brines.
where:
16.2 The test method is applicable in the range from 0.1 to
10 mg/L of chromium. The range may be extended to concen-
W = chromium found in the sample, mg/L (see 13.6),
S
W = chromium found in the sample blank, mg/L(see 13.6), trations greater than 10 mg/L by dilution of the sample.
B
and
16.3 It is the user’s responsibility to ensure the validity of
S = volume of sample used, mL (see 13.2).
this test method for waters of untested matrices.
15. Precision and Bias
17. Summary of Test Method
15.1 The collaborative test data were obtained on reagent 17.1 Chromium is determined by atomic absorption spec-
grade water Types I, II, and III, tap water, 10 % NaCl solution, trophotometry. Dissolved chromium is determined by aspirat-
treated water from a synthetic organic industrial plant which ing a portion of the filtered sample directly with no pretreat-
meets NPDES permit requirements, EPA-extraction procedure ment. Total recoverable chromium is determined by aspirating
D1687 − 17
the sample following hydrochloric-nitric acid digestion and centrated HCl is specified for the preparation of a reagent or in
filtration. The same digestion procedure is used to determine the procedure, use double the amount specified if a distilled
total recoverable cadmium (Test Methods D3557), nickel (Test acid is used.)
Methods D1886), cobalt (Test Methods D3558), copper (Test
20.4 8-Hydroxyquinoline Solution (100 g/L)—Dissolve 50 g
Methods D1688), iron (Test Methods D1068), lead (Test
of 8-hydroxyquinoline in 35 mLof HCl (sp gr 1.19).Warm the
Methods D3559), manganese (Test Methods D858) and zinc
mixture gently on a hot plate to facilitate dissolution. Transfer
(Test Methods D1691).
to a 500-mL volumetric flask and bring to volume with the
careful addition of water. Use a hood.
18. Interferences
20.5 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
18.1 Iron, nickel, and cobalt at 100 µg/L and magnesium at
(HNO ).
30 mg/L interfere by depressing the absorption of chromium.
NOTE 7—If a high reagent blank is obtained, distill the HNO or use a
These interferences are eliminated in solutions containing
spectrograde acid.
10,000 mg/L of 8-hydroxyquinoline. Samples adjusted to this
20.6 NitricAcid(1 + 499)—Add1volumeofHNO (spgr
concentration show no interference from 700 mg/Lof iron and 3
1.42) to 499 volumes of water.
10 mg/L each of nickel and cobalt, or from 1000 mg/L of
magnesium.
20.7 Oxidant:
20.7.1 Air that has been passed through a suitable filter to
18.2 Potassium above 500 mg/L enhances the chromium
remove oil, water, and other foreign substances, is the usual
absorption.
oxidant.
18.3 Sodium, sulfate, and chloride (9000 mg/L each), cal-
20.7.2 Nitrous Oxide, medical grade, is satisfactory.
cium and magnesium (4000 mg/L each), nitrate (2000 mg/L),
20.8 Fuel:
and cadmium, lead, copper, and zinc, (10 mg/L each) do not
20.8.1 Acetylene—Standard, commercially available acety-
interfere.
lene is the usual fuel. Acetone, always present in acetylene
cylinders, can affect analytical results. The cylinder should be
19. Apparatus and Materials
replaced at 345 kPa (50 psi). (Warning—“Purified” grade
19.1 Atomic Absorption Spectrophotometer, for use at 357.9
acetylene containing a special proprietary solvent rather than
nm. A general guide for the use of flame atomic absorption
acetone should not be used with poly(vinyl chloride) tubing as
applications is given in Practice D4691.
weakeningofthetubingwallscancauseahazardoussituation.)
NOTE 5—The manufacturer’s instructions should be followed for all
20.9 Filter Paper—See 11.8.
instrumental parameters.Wavelengths other than 357.9 nm may be used if
they have been determined to be equally suitable.
21. Standardization
19.1.1 Chromium Hollow Cathode Lamp, multielement
21.1 Prepare 100 mL each of a blank and at least four
hollow-cathode lamps.
standard solutions, containing 1 mL of 8-hydroxyquinoline
19.2 Oxidant—See 20.7. solution (100 g/L)/10 mL of standard, to bracket the expected
chromium concentration range of the samples to be analyzed,
19.3 Fuel—See 20.8.
by diluting the standard chromium solution (see 20.2) with
19.4 Pressure-Reducing Valves—The supplies of fuel and
HNO (1 + 499). Prepare the standards each time the test is to
oxidant shall be maintained at pressures somewhat higher than
be performed.
the controll
...

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: D1687 − 12 D1687 − 17
Standard Test Methods for
Chromium in Water
This standard is issued under the fixed designation D1687; 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 hexavalent and total chromium in water. Section 34 on Quality Control
pertains to these test methods. Three test methods are included as follows:
Concentration
Test Method Sections
Range
A—Photometric Diphenyl- 0.01 to 0.5 7 – 15
carbohydrazide mg⁄L
B—Atomic 0.1 to 10 16 – 24
Absorption, mg⁄L
Direct
C—Atomic Absorption, 5 to 100 25 – 33
Graphite μg⁄L
Furnace
Concentration
Test Method Sections
Range
A—Photometric Diphenyl- 0.01 to 0.5 7 – 15
carbohydrazide mg/L
B—Atomic 0.1 to 10 16 – 24
Absorption, mg/L
Direct
C—Atomic Absorption, 5 to 100 25 – 33
Graphite μg/L
Furnace
1.2 Test Method A is a photometric method that measures dissolved hexavalent chromium only. Test Hexavalent chromium can
also be determined by ion chromatography, see Test Method D5257. Test Methods B and C are atomic absorption methods that
are generally applicable to the determination of dissolved or total recoverable chromium in water without regard to valence state.
ICP-MS or ICP-AES may also be appropriate but at a higher instrument cost. See Test Methods D5673 and D1976.
1.3 Test Method A has been used successfully with reagent grade water Types I, II, and III, tap water, 10 % NaCl solution,
treated water from a synthetic organic industrial plant that meets National Pollution Discharge Elimination System (NPDES)
permit requirements, and EPA-extraction procedure leachate water, process water, lake water, effluent treatment, that is, lime
neutralization and precipitation of spent pickle liquor and associated rinse water from stainless steel pickling. Test Method C has
been used successfully with reagent water, stock scrubber water, lake water, filtered tap water, river water, well water, production
plant water, and a condensate from a medium BTU coal gasification process. Matrices used, except for reagent water, are not
available for Test Method B. It is the user’s responsibility to ensure the validity of these test methods for waters of untested
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 4.2, 20.3, and Note 620.8.1 and Note 7.
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 August 2007July 2017. Originally approved in 1959. Last previous edition approved in 20072012 as
D1687 – 02D1687 – 12.(2007)E01. DOI: 10.1520/D1687-12.10.1520/D1687-17.
*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
D1687 − 17
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
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
D1688 Test Methods for Copper 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
D4691 Practice for Measuring Elements in Water by Flame Atomic Absorption Spectrophotometry
D4841 Practice for Estimation of Holding Time for Water Samples Containing Organic and Inorganic Constituents
D5257 Test Method for Dissolved Hexavalent Chromium in Water by Ion Chromatography
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
E60 Practice for Analysis of Metals, Ores, and Related Materials by Spectrophotometry
E275 Practice for Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers
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 Laboratory Control Sample,laboratory control sample, n—a solution with the certified concentration(s) of the analytes.
3.2.4 total recoverable chromium, n—a descriptive term relating to the forms of chromium recovered in the acid-digestion
procedure specified in this test standard.
4. Significance and Use
4.1 Hexavalent chromium salts are used extensively in metal finishing and plating applications, in anodizing aluminum, and in
the manufacture of paints, dyes, explosives, and ceramics. Trivalent chromium salts are used as mordants in textile dyeing, in the
ceramic and glass industry, in the leather industry as a tanning agent, and in photography. Chromium may be present in wastewater
from these industries and may also be discharged from chromate-treated cooling waters.
4.2 The hexavalent state of chromium is toxic to humans, animals, and aquatic life. It can produce lung tumors when inhaled
and readily induces skin sensitization.
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.
D1687 − 17
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, II, or III water. Type I is preferred and more commonly used. Type II water was specified at the time
of round robin testing of these test methods.
NOTE 1—The user must ensure the type of reagent water chosen is sufficiently free of interferences. The water should be analyzed using the test method.
6. Sampling
6.1 Collect the sample in accordance with the applicable ASTM standard as follows: Practice D1066, or PracticePractices
D3370. The holding time for the samples may be calculated in accordance with Practice D4841.
6.2 Samples to be analyzed by Test Method A should be stabilized upon collection by addition of sodium hydroxide solution
to a pH greater than or equal to 8, or analyzed immediately. Minor delays in stabilization or analyses of samples containing sulfur
reduction compounds can produce significant loss in hexavalent chromium. Acidic samples containing hypobromite, persulfate, or
chlorine could oxidize trivalent chromium, if present, to hexavalent form upon preservation, resulting in a positive interference.
When the presence of these oxidizing compounds is suspected, samples should not be preserved but analyzed immediately. It will
be evident that in this case, the simultaneous presence of reducing compounds could not be anticipated.
6.3 Samples to be analyzed by Test Methods B and C shall be preserved by addition of HNO (sp gr 1.42) to pH of 2 or less
immediately at the time of collection, normally about 2 mL HNO /L. If only dissolved chromium is to be determined, the sample
shall be filtered through a 0.45-μm membrane filter (11.8) before acidification.
NOTE 2—Alternatively, the pH may be adjusted in the laboratory if the sample is returned within 14 days. within 14 days of collection. 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.appropriate
TEST METHOD A—PHOTOMETRIC DIPHENYLCARBOHYDRAZIDE
7. Scope
7.1 This test method covers the determination of dissolved hexavalent chromium in water.
7.2 The test method is applicable in the range from 0.01 to 0.5 mg/L chromium. The range may be extended by appropriate
sample dilution.
7.3 This test method has been used successfully with reagent grade water Types I, II, and III, tap water, 10 % NaCl solution,
treated water from a synthetic organic industrial plant that meets NPDES permit requirements, EPA-extraction procedure leachate
water, process water, lake water, effluent from treatment that is, lime neutralization and precipitation of spent pickle liquor and
associated rinse water from stainless steel pickling. It is the responsibility of the user to ensure the validity of the test method to
waters of untested matrices.
7. Scope
7.1 This test method covers the determination of dissolved hexavalent chromium in water.
7.2 The test method is applicable in the range from 0.01 to 0.5 mg/L chromium. The range may be extended by appropriate
sample dilution.
7.3 This test method has been used successfully with reagent grade water Types I, II, and III, tap water, 10 % NaCl solution,
treated water from a synthetic organic industrial plant that meets NPDES permit requirements, EPA-extraction procedure leachate
water, process water, lake water, effluent from treatment that is, lime neutralization and precipitation of spent pickle liquor and
associated rinse water from stainless steel pickling. It is the responsibility of the user to ensure the validity of the test method to
waters of untested matrices.
8. Summary of Test Method
8.1 Hexavalent chromium reacts with 1.5-diphenylcarbohydrazide (s-diphenylcarbazide) in an acid medium to produce a
reddish-purple color. The intensity of the color formed is proportional to the hexavalent chromium concentration.
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 Analar 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.
D1687 − 17
9. Interferences
9.1 Vanadium, titanium, or iron present at concentrations of 5 mg/L yield a 10 to 30 % reduction in recovery of chromium.
Copper at 100 mg/L yields a 20 to 30 % reduction in recovery in the presence of sulfate. Mercury gives a blue-purple color, but
the reaction is not very sensitive at the pH employed for the test.
9.2 Nitrite concentrations in excess of 10 mg/L as NO yield low test results. Sulfamic acid may be added (;10.1 g) prior to
the addition of diphenylcarbazide solution to minimize nitrite interference. Add sulfamic acid only when the presence of nitrite has
been positively established. Excess sulfamic acid itself creates a slightly positive interference.
9.3 Sulfide and sulfite reduce chromate in an acid medium to give low results.
9.4 Several sample matrices have been identified which produce a yellow-orange complex that interferes with this
quantification. When this occurs, it may be remedied by inverting the indicator-buffer sequence. In these cases the analyst should
evaluate the matrix effect with the additions of spikes.spikes (Guide D5810)).
9.5 Although each interferent has been reported, most of the common interferences are eliminated by the preservation procedure
at the time of collection. The potentially interfering metals are precipitated and the reducing effect of sulfur compounds has been
overcome.
10. Apparatus
10.1 Photometer—Spectrophotometer or filter photometer suitable for use at 540 nm and equipped with a cell having a
minimum path length of 10 mm. The photometers and photometric practice prescribed in this test method shall conform to Practice
E60. Spectrophotometers and spectrophotometric practice shall conform to Practice E275.
11. Reagents and Materials
11.1 Chromium Solution, Stock (1 mL = 0.10 mg Cr)—Dissolve 0.2828 g of potassium dichromate (K Cr O that has been oven
2 2 7
dried at 105°C for 1 h) in water. Dilute to 1 L with water. Alternatively, certified stock solutions are commercially available through
chemical supply vendors and may be used.
11.2 Chromium Solution, Standard (1 mL = 0.001 mg Cr)—Dilute 10.0 mL of chromium stock solution (see 11.1) to 1 L with
water.
11.3 Diphenylcarbazide Indicator Solution—Dissolve 0.25 g of powdered 1,5-diphenylcarbohydrazide in 100 mL of acetone.
Store in an amber glass-stoppered flask at 4°C when not in use. This solution is stable for about one week when kept refrigerated.
Prepare fresh reagent when the solution becomes discolored.
NOTE 3—Allow the indicator solution to warm to room temperature before use.
11.4 Phosphoric Acid (1 + 1)—Dilute 500 mL of concentrated phosphoric acid (sp gr 1.69) to 1 L with water.
11.5 Phosphoric Acid (1 + 19)—Dilute 50 mL of concentrated phosphoric acid (sp gr 1.69) to 1 L with water.
11.6 Sodium Hydroxide Solution (40 mg/L)—Dissolve 40 mg of sodium hydroxide (NaOH) in water. Cool and dilute to 1 L.
This solution is used for sample preservation.
11.7 Sulfamic Acid(NH SO H)—Crystals.
2 3
11.8 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.
12. Calibration
12.1 Prepare a series of at least four standard solutions containing from 0 to 0.50 mg/L of chromium by diluting measured
volumes of the standard chromium solution (see 11.2) to 100 mL with water in separate volumetric flasks.
12.2 Transfer 50 mL of each prepared standard solution to separate 125-mL Erlenmeyer flasks and proceed with 13.3 – 13.6.
12.3 Prepare a calibration curve by plotting milligrams per liter of chromium versus absorbance on linear graph paper.
12.4 A calibration curve must be prepared Read directly in concentration if this capability is provided with the instrument or
prepare a calibration curve for each photometer. A recalibration must be made if any alterations of the instrument are made or if
new reagents are prepared. At the least, a blank and three chromium standard solutions must be analyzed to verify the original test
calibration each time the test is performed.
13. Procedure
13.1 Filter a portion of the sample through a 0.45-μm membrane filter (11.8) and adjust the pH into the 8 to 8.5 range if it is
greater than 8.5 with a few drops of the phosphoric acid solution (1 + 19).
D1687 − 17
TABLE 1 Determination of Bias and Precision, Photometric Diphenylcarbohydrazide
Amount Mean Statistically
Added, Recovery ± Bias ± % Bias Significant S S
T 0
mg/L (X¯), mg/L at 5 % Level
Reagent water:
Reagent water 0.010 0.0125 + 0.0025 + 25.0 yes 0.006 0.0031
0.010 0.0125 +0.0025 +25.0 yes 0.006 0.0031
0.050 0.0502 + 0.0002 + 0.40 no 0.007 0.0053
0.050 0.0502 +0.0002 +0.40 no 0.007 0.0053
0.350 0.3484 −0.0016 −0.46 no 0.022 0.0130
0.500 0.4964 −0.0036 −0.72 no 0.022 0.0139
Water of choice:
Water of choice 0.010 0.0112 + 0.0012 + 12.0 no 0.005 0.0025
0.010 0.0112 +0.0012 +12.0 no 0.005 0.0025
0.050 0.0468 −0.0032 −6.40 yes 0.007 0.0042
0.350 0.3378 −0.0122 −3.49 yes 0.026 0.0159
0.500 0.4776 −0.0224 −4.48 yes 0.038 0.0204
Leachate:
Leachate 0.010 0.0148 + 0.0048 + 48.0 yes 0.008 0.0037
0.010 0.0148 +0.0048 +48.0 yes 0.008 0.0037
0.050 0.0513 + 0.0013 + 2.60 no 0.009 0.0062
0.050 0.0513 +0.0013 +2.60 no 0.009 0.0062
0.350 0.3422 −0.0078 −2.23 yes 0.015 0.0093
0.500 0.4887 −0.0113 −2.26 yes 0.025 0.0130
13.2 Transfer 50.0 mL of the filtered sample, or a smaller aliquot of sample diluted to 50.0 mL, to a 125-mL Erlenmeyer flask.
13.3 Add 2.0 mL of the diphenylcarbazide solution to each solution and swirl to mix.
NOTE 4—If the sample is colored, prepare a separate aliquot as described in 13.1 and 13.2. Add 2.0 mL of acetone instead of diphenylcarbazide solution
and proceed with 13.4 and 13.5. Use this solution as the sample blank.
13.4 Immediately add 5.0 mL of phosphoric acid solution (1 + 1) to each solution and swirl to mix.
13.5 Permit the solutions to stand 15 min for full color development. Measure the absorbance within 30 min after the addition
of the diphenylcarbazide solution at 540 nm with a cell having a minimum path length of 10 mm.
+6
13.6 Determine milligrams per liter of chromium as Cr in the test sample by referring the direct instrument reading or the
absorbance to the prepared calibration curve (see 12.3).
14. Calculation
14.1 Calculate the hexavalent chromium concentration as follows:
Cr , mg/L5 W 2 W 50/S (1)
~ !~ !
S B
where:
W = chromium found in the sample, mg/L (see 13.6),
S
W = chromium found in the sample blank, mg/L (see 13.6), and
B
S = volume of sample used, mL (see 13.2).
15. Precision and Bias
15.1 The collaborative test data were obtained on reagent grade water Types I, II, and III, tap water, 10 % NaCl solution, treated
water from a synthetic organic industrial plant which meets NPDES permit requirements, EPA-extraction procedure leachate water,
process water, lake water, effluent from treatment, that is, lime neutralization and precipitation of spent pickle liquor and associated
rinse water from stainless steel pickling.
15.2 Single-operator and overall precision of this test method within its designated range and recovery data for the above waters
for 16 laboratories, which include a total of 16 operators analyzing each sample on three different days, is given in Table 1.
15.3 Single-operator and overall precision of this test method within its designated range and recovery data for a prepared
leachate water for 8 laboratories, which include a total of 8 operators analyzing each sample on three different days, is also given
in Table 1.
15.4 It is the user’s responsibility to ensure the validity of the test method for waters of untested matrices.
15.5 Precision and bias for this test method conforms to Practice D2777 – 77, which was in place at the time of collaborative
testing. Under the allowances made in 1.4 of Practice D2777 – 08, – 13, these precision and bias data do meet existing
requirements for interlaboratory studies of Committee D19 test methods.
D1687 − 17
TEST METHOD B—ATOMIC ABSORPTION, DIRECT ABSORPTION, DIRECT
16. Scope
16.1 This test method covers the determination of dissolved and total recoverable chromium in most waters, wastewaters, and
brines.
16.2 The test method is applicable in the range from 0.1 to 10 mg/L of chromium. The range may be extended to concentrations
greater than 10 mg/L by dilution of the sample.
16.3 It is the user’s responsibility to ensure the validity of this test method for waters of untested matrices.
16. Scope
16.1 This test method covers the determination of dissolved and total recoverable chromium in most waters, wastewaters, and
brines.
16.2 The test method is applicable in the range from 0.1 to 10 mg/L of chromium. The range may be extended to concentrations
greater than 10 mg/L by dilution of the sample.
16.3 It is the user’s responsibility to ensure the validity of this test method for waters of untested matrices.
17. Summary of Test Method
17.1 Chromium is determined by atomic absorption spectrophotometry. Dissolved chromium is determined by aspirating a
portion of the filtered sample directly with no pretreatment. Total recoverable chromium 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), nickel (Test Methods D1886), cobalt (Test Methods D3558), copper (Test Methods D1688), iron
(Test Methods D1068), lead (Test Methods D3559), manganese (Test Methods D858) and zinc (Test Methods D1691).
18. Interferences
18.1 Iron, nickel, and cobalt at 100 μg/L and magnesium at 30 mg/L interfere by depressing the absorption of chromium. These
interferences are eliminated in solutions containing 10,000 mg/L of 8-hydroxyquinoline. Samples adjusted to this concentration
show no interference from 700 mg/L of iron and 10 mg/L each of nickel and cobalt, or from 1000 mg/L of magnesium.
18.2 Potassium above 500 mg/L enhances the chromium absorption.
18.3 Sodium, sulfate, and chloride (9000 mg/L each), calcium and magnesium (4000 mg/L each), nitrate (2000 mg/L), and
cadmium, lead, copper, and zinc, (10 mg/L each) do not interfere.
19. Apparatus and Materials
19.1 Atomic Absorption Spectrophotometer , Spectrophotometer, for use at 357.9 nm. A general guide for the use of flame
atomic absorption applications is given in Practice D4691.
NOTE 5—The manufacturer’s instructions should be followed for all instrumental parameters. Wavelengths other than 357.9 nm may be used if they
have been determined to be equally suitable.
19.1.1 Chromium Hollow Cathode Lamp, multielement hollow-cathode lamps.
19.2 Oxidant: Oxidant—
19.2.1 Air that has been passed through a suitable filter to remove oil, water, and other foreign substances, is the usual
oxidant.See 20.7.
19.2.2 Nitrous Oxide, medical grade, is satisfactory.
19.3 Fuel: Fuel—
19.3.1 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).
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 hazardous situation.See 20.8.
19.4 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.
20. Reagents and Materials
20.1 Chromium Solution, Stock (1 mL = 1.0 mg Cr)—Dissolve 2.828 g of primary standard potassium dichromate (K Cr O )
2 2 7
in 200 mL of water and dilute to 1 L. Alternatively, certified stock solutions are commercially available through chemical supply
vendors and may be used.
D1687 − 17
20.2 Chromium Solution, Standard (1 mL = 0.1 mg Cr)—Dilute 100.0 mL of the chromium stock solution and 1 mL of HNO
(sp gr 1.42) to 1 L with water.
20.3 Hydrochloric Acid (sp gr 1.19)—Concentrated hydrochloric acid (HCl).
NOTE 6—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 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 for the preparation of a reagent or in the procedure, use double the amount specified if a distilled
acid is used.)
20.4 8-Hydroxyquinoline Solution (100 g/L)—Dissolve 50 g of 8-hydroxyquinoline in 35 mL of HCl (sp gr 1.19). Warm the
mixture gently on a hot plate to facilitate dissolution. Transfer to a 500-mL volumetric flask and bring to volume with the careful
addition of water. Use a hood.
20.5 Nitric Acid (sp gr 1.42)—Concentrated nitric acid (HNO ).
NOTE 7—If a high reagent blank is obtained, distill the HNO or use a spectrograde acid.
20.6 Nitric Acid (1 + 499)—Add 1 volume of HNO (sp gr 1.42) to 499 volumes of water.
20.7 Oxidant:
20.7.1 Air that has been passed through a suitable filter to remove oil, water, and other foreign substances, is the usual oxidant.
20.7.2 Nitrous Oxide, medical grade, is satisfactory.
20.8 Fuel:
20.8.1 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).
...