ASTM D7511-09

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D7511 – 09
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.
1. Scope D3370 Practices for Sampling Water from Closed Conduits
D3856 Guide for Good Laboratory Practices in Laborato-
1.1 This method is used for determining total cyanide in
ries Engaged in Sampling and Analysis of Water
drinking and surface waters, as well as domestic and industrial
-
D4210 Practice for Intralaboratory Quality Control Proce-
wastes. Cyanide ion (CN ), hydrogen cyanide in water (HC-
dures and a Discussion on Reporting Low-Level Data
N(aq)), and the cyano-complexes of zinc, copper, cadmium,
D5847 Practice for Writing Quality Control Specifications
mercury, nickel, silver, and iron may be determined by this
for Standard Test Methods for Water Analysis
method. Cyanide ions from Au(I), Co(III), Pd(II), and Ru(II)
D6696 Guide for Understanding Cyanide Species
complexes are only partially determined.
D7365 Practice for Sampling, Preservation and Mitigating
1.2 The method detection limit (MDL) is 1.0 µg/L cyanide
Interferences in Water Samples for Analysis of Cyanide
andtheminimumlevel(ML)is3µg/L.Theapplicablerangeof
the method is 3 to 500 µg/L cyanide using a 200-µL sample
3. Terminology
loop. Extend the range to analyze higher concentrations by
3.1 Definitions—For definitions of terms used in this test
sample dilution or changing the sample loop volume.
method, refer to Terminology D1129 and Guide D6696.
1.3 This method can be used by analysts experienced with
3.1.1 total cyanide—refers to all cyanide-containing com-
equipment using segmented flow analysis (SFA) and flow
pounds in a sample, including free cyanide, WAD cyanide
injectionanalysis(FIA)orworkingundertheclosesupervision
compounds, and strong metal cyanide complexes.
of such qualified persons.
1.4 The values stated in SI units are to be regarded as
4. Summary of Test Method
standard. No other units of measurement are included in this
4.1 Prior to analysis, treat the sample to remove potential
standard.
interferences (Sections 4 and 8). Ultraviolet (UV) digestion
1.5 This standard does not purport to address all of the
releases cyanide from cyanide complexes. Acid addition con-
safety concerns, if any, associated with its use. It is the
verts cyanide ion to hydrogen cyanide gas (HCN), which
responsibility of the user of this standard to establish appro-
passes under a gas diffusion membrane. The hydrogen cyanide
priate safety and health practices and determine the applica-
gas diffuses through the membrane into an alkaline receiving
bility of regulatory limitations prior to use. Specific hazard
solution, where it converts back to cyanide ion. A silver
statements are given in Note 2 and Section 9.
working electrode, silver/silver chloride reference electrode,
2. Referenced Documents and platinum/stainless steel counter electrode at an applied
2 potential of zero volt amperometrically monitor the cyanide
2.1 ASTM Standards:
ion. The current generated is proportional to the cyanide
D1129 Terminology Relating to Water
concentration present in the original sample.
D1193 Specification for Reagent Water
4.2 Calibrations and data are processed with the instru-
D2036 Test Methods for Cyanides in Water
ment’s data acquisition software.
D2777 Practice for Determination of Precision and Bias of
Applicable Test Methods of Committee D19 on Water
5. Significance and Use
5.1 Cyanide and hydrogen cyanide are highly toxic. Regu-
lations have been established to require the monitoring of
This test method is under the jurisdiction of ASTM Committee D19 on Water
cyanide in industrial and domestic wastewaters and surface
andisthedirectresponsibilityofSubcommitteeD19.06onMethodsforAnalysisfor
Organic Substances in Water. waters.
Current edition approved Feb. 15, 2009. Published March 2009. DOI: 10.1520/
D7511-09.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Withdrawn. The last approved version of this historical standard is referenced
Standards volume information, refer to the standard’s Document Summary page on on www.astm.org.
the ASTM website. 40 CFR Part 136.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7511 – 09
5.2 This test method is applicable for natural water, saline 6.8 Nitrate and nitrite if treated with sulfamic acid do not
waters, and wastewater effluent. interfere in this method.
5.3 The method may be used for process control in waste- 6.9 Sodiumsulfite,sulfurdioxide,orsodiumbisulfitedonot
-
water treatment facilities. interfere at up to 2000 ppm SO .
5.4 The spot test outlined in Test Methods D2036, Annex 6.10 Sodium Thiosulfate exhibits a slight positive bias at
A1 can be used to detect cyanide and thiocyanate in water or concentrations above 200 ppm. This positive bias may be
wastewater, and to approximate its concentration. removed by increasing the amount of Bismuth Nitrate in the
TA2 reagent.
6. Interferences
6.11 Samplescontainingparticulatesshouldbefilteredprior
to analysis. Extract and combine filtered extract with original
6.1 Method interferences can be caused by contaminants in
sample prior to analysis, or measure the filtered extract and the
the reagents, reagent water, glassware, etc., which may bias the
aqueous sample separately and combine results mathemati-
results. Take care to keep all such items free of contaminants.
cally.
6.2 Sulfide and sulfide-containing compounds are positive
interferents in this method. When acidified, sulfide forms
7. Apparatus
hydrogen sulfide, which passes through the gas diffusion
7.1 The instrument should be equipped with a precise
membrane and produces a signal at the silver electrode. In
sampleintroductionsystem,aUVdigesterwitha312-nmlamp
addition, sulfide ion reacts with cyanide ion in solution to
andTFE-efluorocarbon digestion coil, a gas diffusion manifold
reduce its concentration over time. Treat samples containing
with hydrophobic membrane, and an amperometric detection
sulfide according to Section 11.4. During UV digestion, some
system to include a silver working electrode, an Ag/AgCl
sulfur compounds may produce sulfide.TA2 reagent contains a
2-
reference electrode, and a Pt or stainless steel counter elec-
sulfide scrubber that can remove up to 50 mg/L S from the
trode. Examples of the apparatus schematics are shown in Fig.
system prior to amperometric detection.
1. Example instrument settings are shown in Table 1.
6.3 Treat sample containing water-soluble aldehydes, such
as formaldehyde or acetaldehyde, by adding ethylenediamine
NOTE 1—The instrument settings in Table 1 are only examples. The
solution.
analyst may modify the settings as long as performance of the method has
6.4 Remove oxidizing agents that decompose cyanides by
notbeendegraded.Contacttheinstrumentmanufacturerforrecommended
adding ascorbic acid, or sodium arsenite. instrument parameters.
6.5 Thiocyanate can produce positive interference when
7.2 An autosampler is recommended but not required to
they decompose to cyanide by UV irradiation or oxidation.
automate sample injections and increase throughput. Auto
This method uses 312 nm as the irradiation wavelength, which
samplers are usually available as an option from the instru-
keeps thiocyanate interference from UV irradiation minimal.
ment’s manufacturer.
Use of Total Acid Reagent–Modified, TA1M (see 8.21) mini-
7.3 Data Acquisition System—Use the computer hardware
mizes interference from thiocyanate.
and software recommended by the instrument manufacturer to
6.6 High concentrations of carbonate can result in a nega-
control the apparatus and to collect data from the detector.
tive response in the amperometric detector when carbon
7.4 Pump Tubing—Use tubing recommended by instrument
dioxide diffuses across the gas diffusion membrane into the
manufacturer. Replace pump tubing when worn, or when
alkaline receiving solution, reducing its pH. Treat effluents
precision is no longer acceptable.
from high carbonate containing wastes, such as coal gasifica-
tion waste and atmospheric emission scrub water, with hy-
drated lime to stabilize the sample.
The sole source of supply of the apparatus known to the committee at this time
is the trademarked CNSolution equipped with an amperometric flow cell, gas
6.7 High concentrations of surfactants interfere by changing
diffusion, and UV digestion module, available from OIAnalytical. If you are aware
the characteristics of the gas diffusion membrane, allowing
of alternative suppliers, please provide this information to ASTM International
acid solution to pass through the membrane and enter the
Headquarters.Your comments will receive careful consideration at a meeting of the
detector. responsible technical committee, which you may attend.
FIG. 1 Flow Injection Analysis Apparatus 1
D7511 – 09
TABLE 1 Flow Injection Analysis Parameters
8.5.4 Record the results of the titration and calculate the
FIA Instrument Parameter Recommended Method Setting cyanideconcentrationoftheStockCyanideSolutionaccording
to the equation in 8.18.2.
Pump Flow Rates 0.5 to 2 mL/min
Cycle period (total) 90 to 250 s/sample
8.5.5 Use the actual calculated cyanide concentration in all
Sample load period At least enough time to completely
subsequent calculations of working standard concentrations.
fill the sample loop
Reagent water rinse time At least 15 seconds
8.6 Intermediate Cyanide Standards:
between samples
-
8.6.1 Intermediate Standard 1 (100 µg/mL CN )—Pipette
Peak Evaluation Peak height or area
Working Potential 0.0 V vs Ag/AgCl 10.0 mL of stock cyanide solution (see 8.5) into a 100 mL
volumetric flask containing 1 mL of 1.0 M NaOH (see 8.3).
Dilute to volume with laboratory water. Store under refrigera-
7.5 Gas Diffusion Membranes—A hydrophobic membrane
tion. The standard should be stable for at least 2 weeks.
which allows gaseous hydrogen cyanide to diffuse from the -
8.6.2 Intermediate Cyanide Solution 2 (10 µg/mL CN )—
donor to the acceptor stream at a sufficient rate to allow
Pipette 10.0 mLof Intermediate Cyanide Solution 1 (see 8.6.1)
detection. The gas diffusion membrane should be replaced
into a 100 mL volumetric flask containing 1.0 mL of 1.00 M
when the baseline becomes noisy or every 1 to 2 weeks.
NaOH (see 8.3). Dilute to volume with laboratory water. The
7.6 Use parts and accessories as directed by instrument
standard should be stable for at least 2 weeks.
manufacturer.
8.7 Working Cyanide Calibration Standards—Prepare fresh
daily as described in 8.7.1 and 8.7.2 ranging in concentration
8. Reagents and Materials
-
from 3 to 500 µg/L CN .
8.1 Purity of Reagents—Reagent grade chemicals shall be
8.7.1 Calibration Standards (20, 50, 100, 200, and 500 µg/L
used in all tests. Unless otherwise indicated, it is intended that
-
CN )—Pipette 20, 50, 100, 200, and 500 µL of Intermediate
all reagents shall conform to the specifications of theAmerican
7 Standard 1 (see 8.6.1) into separate 100 mL volumetric flasks
Chemical Society, where such specifications are available.
containing1.0mLof1.00MNaOH(see8.3).Dilutetovolume
Other grades may be used, provided it is first ascertained that
with laboratory water.
the reagent is of sufficiently high purity to permit its use
-
8.7.2 Calibration Standards (3 and 10 µg/L CN )—Pipette
without lessening the accuracy of the determination.
30 and 100 µL of Intermediate Cyanide Solution 2 (see 8.6.2)
8.2 Purity of Water—Unless otherwise indicated, references
into separate 100 mL volumetric flasks containing 1.0 mL of
to water shall be understood to mean interference free reagent
1.00 M NaOH (see 8.3). Dilute to volume with laboratory
water conforming to Type I or Type II grade of Specification
water.
D1193.
8.3 Sodium Hydroxide Solution (1.00 M)—Dissolve 40 g 8.8 Cyanide Electrode Stabilization Solution (Approxi-
-
mately 5 ppm as CN )—Pipette 500 µL of Stock Cyanide (see
NaOH in laboratory water and dilute to 1 L.
8.4 Acceptor Solution (0.10 M NaOH)—Dissolve 4.0 g 8.5) into a 100 mL volumetric flask containing 1.0 mL of 1.00
M NaOH (see 8.3). Dilute to volume with laboratory water.
NaOH in laboratory water and dilute to 1 L.
-
8.5 Stock Cyanide Solution (1000 µg/mL CN )—Dissolve The solution should be stored under refrigeration.
2.51 g of KCN and 2.0 g of NaOH in 1 Lof water. Standardize
8.9 Acetate Buffer—Dissolve 410 g of sodium acetate tri-
withsilvernitratesolutionasdescribedin8.5.1-8.5.4.Storethe
hydrate(NaC H O ·3H O)in500mLoflaboratorywater.Add
2 3 2 2
solution under refrigeration and check concentration approxi-
glacialaceticacid(approximately500mL)toyieldapHof4.5.
mately every 6 months and correct if necessary.
8.10 Iron (II) Cyanide Stock Solution—Weigh 0.2706 g
K [Fe(CN) ]·3H O into a 100 mL volumetric flask. Place 1.0
NOTE 2—Warning: Because KCN is highly toxic, avoid contact or 4 6 2
mLof 1.00 M NaOH (see 8.3) in the flask and dilute to volume
inhalation.
with laboratory water. The solution must be stored in an amber
8.5.1 Pipet 100 mLof Stock Cyanide Solution (see 8.5) into
glass bottle under refrigeration at 4°C.
a 250 mL flask or beaker.
8.11 Iron (II) Cyanide Intermediate Solution—Pipet 10.0
8.5.2 Add0.5mLofrhodanineindicatorsolution(see8.17).
mLof the iron (II) cyanide stock solution (see 8.10) into a 100
8.5.3 Titrate with standardized silver nitrate solution (see
mL volumetric flask containing 1.0 mL of 1.00 M NaOH (see
8.18 and 8.18.2) to the first color change from yellow to
8.3). Dilute to volume with laboratory grade water. The
salmon pink.
solution must be stored in an amber glass bottle under
refrigeration at 4°C.
The sole source of supply of the apparatus known to the committee at this time
8.12 Iron (II) Cyanide Recovery Solution—Pipet 100 µL of
is OI Analytical Part Number A001520 and Pall Corporation Part Number
iron(II)cyanideintermediatesolution(see8.11)intoa100mL
M5PU025. If you are aware of alternative suppliers, please provide this information
to ASTM International Headquarters. Your comments will receive careful consid-
volumetric flask containing 1.0 mLof 1.00 M NaOH (see 8.3).
eration at a meeting of the responsible technical committee, which you may attend.
Dilute to volume with laboratory water. Prepare fresh daily.
Reagent Chemicals, Am
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