ASTM D7511-12(2017)e1
(Test Method)Standard Test Method for Total Cyanide by Segmented Flow Injection Analysis, In-Line Ultraviolet Digestion and Amperometric Detection
Standard Test Method for Total Cyanide by Segmented Flow Injection Analysis, In-Line Ultraviolet Digestion and Amperometric Detection
SIGNIFICANCE AND USE
5.1 Cyanide and hydrogen cyanide are highly toxic. Regulations have been established to require the monitoring of cyanide in industrial and domestic wastewaters and surface waters.4
5.2 This test method is applicable for natural water, saline waters, and wastewater effluent.
5.3 This test method may be used for process control in wastewater treatment facilities.
5.4 The spot test outlined in Test Methods D2036, Annex A1, can be used to detect cyanide and thiocyanate in water or wastewater, and to approximate its concentration.
SCOPE
1.1 This test method is used for determining total cyanide in drinking and surface waters, as well as domestic and industrial wastes. Cyanide ion (CN–), hydrogen cyanide in water (HCN(aq)), and the cyano-complexes of zinc, copper, cadmium, mercury, nickel, silver, and iron may be determined by this test method. Cyanide ions from Au(I), Co(III), Pd(II), and Ru(II) complexes are only partially determined.
1.2 The method detection limit (MDL) is 1.0 μg/L cyanide and the minimum level (ML) is 3 μg/L. The applicable range of the method is 3 to 500 μg/L cyanide using a 200-μL sample loop. Extend the range to analyze higher concentrations by sample dilution or changing the sample loop volume.
1.3 This test method can be used by analysts experienced with equipment using segmented flow analysis (SFA) and flow injection analysis (FIA) or working under the close supervision of such qualified persons.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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. Specific hazard statements are given in 8.5 and Section 9.
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
Relations
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.
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Designation: D7511 − 12 (Reapproved 2017)
Standard Test Method for
Total Cyanide by Segmented Flow Injection Analysis, In-Line
Ultraviolet Digestion and Amperometric Detection
This standard is issued under the fixed designation D7511; 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.
ε NOTE—Warning notes were editorially updated throughout in July 2017.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method is used for determining total cyanide in
drinking and surface waters, as well as domestic and industrial D1129 Terminology Relating to Water
–
D1193 Specification for Reagent Water
wastes. Cyanide ion (CN ), hydrogen cyanide in water
(HCN(aq)), and the cyano-complexes of zinc, copper, D2036 Test Methods for Cyanides in Water
D2777 Practice for Determination of Precision and Bias of
cadmium, mercury, nickel, silver, and iron may be determined
by this test method. Cyanide ions from Au(I), Co(III), Pd(II), Applicable Test Methods of Committee D19 on Water
D3370 Practices for Sampling Water from Closed Conduits
and Ru(II) complexes are only partially determined.
D3856 Guide for Management Systems in Laboratories
1.2 The method detection limit (MDL) is 1.0 µg/L cyanide
Engaged in Analysis of Water
andtheminimumlevel(ML)is3µg/L.Theapplicablerangeof
D4210 Practice for Intralaboratory Quality Control Proce-
the method is 3 to 500 µg/L cyanide using a 200-µL sample
dures and a Discussion on Reporting Low-Level Data
loop. Extend the range to analyze higher concentrations by
(Withdrawn 2002)
sample dilution or changing the sample loop volume.
D5847 Practice for Writing Quality Control Specifications
1.3 This test method can be used by analysts experienced
for Standard Test Methods for Water Analysis
with equipment using segmented flow analysis (SFA) and flow
D6696 Guide for Understanding Cyanide Species
injectionanalysis(FIA)orworkingundertheclosesupervision
D7365 Practice for Sampling, Preservation and Mitigating
of such qualified persons.
Interferences in Water Samples for Analysis of Cyanide
1.4 The values stated in SI units are to be regarded as
3. Terminology
standard. No other units of measurement are included in this
3.1 Definitions:
standard.
3.1.1 For definitions of terms used in this standard, refer to
1.5 This standard does not purport to address all of the
Terminology D1129 and Guide D6696.
safety concerns, if any, associated with its use. It is the
3.2 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.2.1 total cyanide, n—referstoallcyanide-containingcom-
priate safety and health practices and determine the applica-
pounds in a sample, including free cyanide, WAD cyanide
bility of regulatory limitations prior to use. Specific hazard
compounds, and strong metal cyanide complexes.
statements are given in 8.5 and Section 9.
1.6 This international standard was developed in accor-
4. Summary of Test Method
dance with internationally recognized principles on standard-
4.1 Prior to analysis, treat the sample to remove potential
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- interferences (Sections 4 and 8). Ultraviolet (UV) digestion
releases cyanide from cyanide complexes. Acid addition con-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee. verts cyanide ion to hydrogen cyanide gas (HCN), which
passes under a gas diffusion membrane. The hydrogen cyanide
1 2
This test method is under the jurisdiction of ASTM Committee D19 on Water For referenced ASTM standards, visit the ASTM website, www.astm.org, or
andisthedirectresponsibilityofSubcommitteeD19.06onMethodsforAnalysisfor contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Organic Substances in Water. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved July 1, 2017. Published July 2017. Originally approved the ASTM website.
in 2009. Last previous edition approved in 2012 as D7511 – 12. DOI: 10.1520/ The last approved version of this historical standard is referenced on
D7511-12R17E01. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D7511 − 12 (2017)
gas diffuses through the membrane into an alkaline receiving from high carbonate containing wastes, such as coal gasifica-
solution, where it converts back to cyanide ion. A silver tion waste and atmospheric emission scrub water, with hy-
working electrode, silver/silver chloride reference electrode, drated lime to stabilize the sample.
and platinum/stainless steel counter electrode at an applied
6.7 High concentrations of surfactants interfere by changing
potential of zero volt amperometrically monitor the cyanide
the characteristics of the gas diffusion membrane, allowing
ion. The current generated is proportional to the cyanide
acid solution to pass through the membrane and enter the
concentration present in the original sample.
detector.
4.2 Calibrations and data are processed with the instru-
6.8 Nitrate and nitrite if treated with sulfamic acid do not
ment’s data acquisition software.
interfere in this test method.
5. Significance and Use
6.9 Sodiumsulfite,sulfurdioxide,orsodiumbisulfitedonot
–
5.1 Cyanide and hydrogen cyanide are highly toxic. Regu- interfere at up to 2000 ppm SO .
lations have been established to require the monitoring of
6.10 Sodium Thiosulfate exhibits a slight positive bias at
cyanide in industrial and domestic wastewaters and surface
concentrations above 200 ppm. This positive bias may be
waters.
removed by increasing the amount of Bismuth Nitrate in the
5.2 This test method is applicable for natural water, saline
TA2 reagent.
waters, and wastewater effluent.
6.11 Samplescontainingparticulatesshouldbefilteredprior
5.3 This test method may be used for process control in
to analysis. Extract and combine filtered extract with original
wastewater treatment facilities.
sample prior to analysis, or measure the filtered extract and the
5.4 The spot test outlined in Test Methods D2036, Annex
aqueous sample separately and combine results mathemati-
A1, can be used to detect cyanide and thiocyanate in water or cally.
wastewater, and to approximate its concentration.
7. Apparatus
6. Interferences
7.1 The instrument should be equipped with a precise
6.1 Test method interferences can be caused by contami-
sampleintroductionsystem,aUVdigesterwitha312-nmlamp
nantsinthereagents,reagentwater,glassware,etc.,whichmay
and UV transparent digestion coil, a gas diffusion manifold
bias the results. Take care to keep all such items free of
with hydrophobic membrane, and an amperometric detection
contaminants.
system to include a silver working electrode, an Ag/AgCl
6.2 Sulfide and sulfide-containing compounds are positive
reference electrode, and a Pt or stainless steel counter elec-
interferents in this test method. When acidified, sulfide forms
trode. Examples of the apparatus schematics are shown in Fig.
hydrogen sulfide, which passes through the gas diffusion
1. Example instrument settings are shown in Table 1.
membrane and produces a signal at the silver electrode. In
NOTE 1—The instrument settings in Table 1 are only examples. The
addition, sulfide ion reacts with cyanide ion in solution to analyst may modify the settings as long as performance of the test method
has not been degraded. Contact the instrument manufacturer for recom-
reduce its concentration over time. Treat samples containing
mended instrument parameters.
sulfide according to 11.4. During UV digestion, some sulfur
compounds may produce sulfide. TA2 reagent contains a
7.2 An autosampler is recommended but not required to
2–
sulfide scrubber that can remove up to 50 mg/L S from the
automate sample injections and increase throughput. Auto
system prior to amperometric detection.
samplers are usually available as an option from the instru-
ment’s manufacturer.
6.3 Treat sample containing water-soluble aldehydes, such
as formaldehyde or acetaldehyde, by adding ethylenediamine
7.3 Data Acquisition System—Use the computer hardware
solution.
and software recommended by the instrument manufacturer to
control the apparatus and to collect data from the detector.
6.4 Remove oxidizing agents that decompose cyanides by
adding ascorbic acid, or sodium arsenite.
7.4 Pump Tubing—Use tubing recommended by instrument
6.5 Thiocyanate can produce positive interference when
manufacturer. Replace pump tubing when worn, or when
they decompose to cyanide by UV irradiation or oxidation.
precision is no longer acceptable.
This test method uses 312 nm as the irradiation wavelength,
7.5 Gas Diffusion Membranes—A hydrophobic membrane
which keeps thiocyanate interference from UV irradiation
which allows gaseous hydrogen cyanide to diffuse from the
minimal. Use of Total Acid Reagent–Modified, TA1M (see
donor to the acceptor stream at a sufficient rate to allow
8.21) minimizes interference from thiocyanate.
6.6 High concentrations of carbonate can result in a nega-
tive response in the amperometric detector when carbon
The sole source of supply of the apparatus known to the committee at this time
dioxide diffuses across the gas diffusion membrane into the
is the trademarked CNSolution equipped with an amperometric flow cell, gas
alkaline receiving solution, reducing its pH. Treat effluents
diffusion, and UV digestion module, available from OIAnalytical. If you are aware
of alternative suppliers, please provide this information to ASTM International
Headquarters.Your comments will receive careful consideration at a meeting of the
4 1
40 CFR Part 136. responsible technical committee, which you may attend.
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D7511 − 12 (2017)
FIG. 1 Flow Injection Analysis Apparatus 1
–
TABLE 1 Flow Injection Analysis Parameters
8.5 Stock Cyanide Solution (1000 µg/mL CN )—Dissolve
FIA Instrument Parameter Recommended Method Setting 2.51 g of KCN and 2.0 g of NaOH in 1 Lof water. Standardize
Pump Flow Rates 0.5 to 2 mL/min with silver nitrate solution as described in 8.5.1 – 8.5.4. Store
Cycle Period (Total) 90 to 250 s/sample
the solution under refrigeration and check concentration ap-
Sample Load Period At least enough time to completely fill
proximately every 6 months and correct if necessary.
the sample loop
Reagent Water Rinse Time Between At least 15 seconds (Warning—Because KCN is highly toxic, avoid contact or
Samples
inhalation.)
Peak Evaluation Peak height or area
8.5.1 Pipet 100 mLof Stock Cyanide Solution (see 8.5) into
Working Potential 0.0 V versus Ag/AgCl
a 250 mL flask or beaker.
8.5.2 Add0.5mLofrhodanineindicatorsolution(see8.17).
8.5.3 Titrate with standardized silver nitrate solution (see
detection. The gas diffusion membrane should be replaced
8.18 and 8.18.2) to the first color change from yellow to
when the baseline becomes noisy or every 1 to 2 weeks.
salmon pink.
7.6 Use parts and accessories as directed by instrument
8.5.4 Record the results of the titration and calculate the
manufacturer. cyanideconcentrationoftheStockCyanideSolutionaccording
to the equation in 8.18.2.
8. Reagents and Materials
8.5.5 Use the actual calculated cyanide concentration in all
8.1 Purity of Reagents—Reagent grade chemicals shall be subsequent calculations of working standard concentrations.
used in all tests. Unless otherwise indicated, it is intended that
8.6 Intermediate Cyanide Standards:
all reagents shall conform to the specifications of theAmerican
–
8.6.1 Intermediate Standard 1 (100 µg/mL CN )—Pipette
Chemical Society, where such specifications are available.
10.0 mL of stock cyanide solution (see 8.5) into a 100 mL
Other grades may be used, provided it is first ascertained that
volumetric flask containing 1 mL of 1.0 M NaOH (see 8.3).
the reagent is of sufficiently high purity to permit its use
Dilute to volume with laboratory water. Store under refrigera-
without lessening the accuracy of the determination.
tion. The standard should be stable for at least 2 weeks.
–
8.2 Purity of Water—Unless otherwise indicated, references
8.6.2 Intermediate Cyanide Solution 2 (10 µg/mL CN )—
to water shall be understood to mean interference free reagent
Pipette 10.0 mLof Intermediate Cyanide Solution 1 (see 8.6.1)
water conforming to Type I or Type II grade of Specification
into a 100 mL volumetric flask containing 1.0 mL of 1.00 M
D1193.
NaOH (see 8.3). Dilute to volume with laboratory water. The
standard should be stable for at least 2 weeks.
8.3 Sodium Hydroxide Solution (1.00 M)—Dissolve 40 g
NaOH in laboratory water and dilute to 1 L.
8.7 Working Cyanide Calibration Standards—Prepare fresh
8.4 Acceptor Solution (0.10 M NaOH)—Dissolve 4.0 g daily as described in 8.7.1 and 8.7.2 ranging in concentration
–
NaOH in laboratory water and dilute to 1 L. from 3 to 500 µg/L CN .
8.7.1 Calibration Standards (20, 50, 100, 200, and 500 µg/L
–
CN )—Pipette 20, 50, 100, 200, and 500 µL of Intermediate
The sole source of supply of the apparatus known to the committee at this time
Standard 1 (see 8.6.1) into separate 100 mL volumetric flasks
is OI Analytical Part Number A001520 and Pall Corporation Part Number
containing1.0mLof1.00MNaOH(see8.3).Dilutetovolume
M5PU025. If you are aware of alternative suppliers, please provide this information
to ASTM International Headquarters. Your comments will receive careful consid- with laboratory water.
eration at a meeting of the responsible technical committee, which you may attend. –
8.7.2 Calibration Standards (3 and 10 µg/L CN )—Pipette
Reagent Chemicals, American Chemical Society Specifications, American
30 and 100 µL of Intermediate Cyanide Solution 2 (see 8.6.2)
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
listed by the American Chemical Society, see Annual Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. Commercially available stock cyanide solutions may be substituted.
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D7511 − 12 (2017)
into separate 100 mL volumetric flasks containing 1.0 mL of 8.18.1 Potassium Chloride (KCl)—Primary Standard—
1.00 M NaOH
...
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