ASTM D7237-06
(Test Method)Standard Test Method for Aquatic Free Cyanide with Flow Injection Analysis (FIA) Utilizing Gas Diffusion Separation and Amperometric Detection
Standard Test Method for Aquatic Free Cyanide with Flow Injection Analysis (FIA) Utilizing Gas Diffusion Separation and Amperometric Detection
SIGNIFICANCE AND USE
Cyanide and hydrogen cyanide are highly toxic. Regulations have been established to require the monitoring of cyanide in industrial and domestic wastes and surface waters.3
It is useful to determine the aquatic free cyanide to establish an index of toxicity when a wastewater is introduced to the pH and temperature of the natural environment.
This test method is applicable for natural water, saline waters, and wastewater effluent.
SCOPE
1.1 This test method is used to establish the concentration of aquatic "free" cyanide in an aqueous wastewater or effluent. The test conditions of this method are used to measure free cyanide (HCN and CN-) and cyanide bound in the metal-cyanide complexes that are easily dissociated into free cyanide ions at the pH of the aquatic environment ranging from pH 6 to pH 8. The extent of HCN formation is less dependent on temperature than the pH; however, the temperature can be regulated if deemed necessary to further simulate the actual aquatic environment.
1.2 The aquatic free cyanide method is based on the same instrumentation and technology that is described in standard test method D 6888, but employs milder conditions (pH 6-8 buffer versus HCl in the reagent stream), and does not utilize ligand displacement reagents.
1.3 The aquatic free cyanide measured by this procedure should be similar to actual levels of HCN in the original aquatic environment. This in turn may give a reliable index of toxicity to aquatic organisms.
1.4 This procedure is applicable over a range of approximately 2 to 500 g/L (parts per billion) aquatic free cyanide. Sample dilution may increase cyanide recoveries depending on the cyanide speciation; therefore, it is not recommended to dilute samples. Higher concentrations can be analyzed by increasing the range of calibration standards or with a lower injection volume. In accordance with Guide E 1763 and Practice D 6512 the lower scope limit was determined to be 9 g/L for chlorinated gold leaching barren effluent water.
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 Section and Section .
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D7237 – 06
Standard Test Method for
Aquatic Free Cyanide with Flow Injection Analysis (FIA)
Utilizing Gas Diffusion Separation and Amperometric
1
Detection
This standard is issued under the fixed designation D7237; 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 bility of regulatory limitations prior to use. Specific hazard
statements are given in Section 8.6 and Section 9.
1.1 Thistestmethodisusedtoestablishtheconcentrationof
aquatic “free” cyanide in an aqueous wastewater or effluent.
2. Referenced Documents
The test conditions of this method are used to measure free
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- 2.1 ASTM Standards:
cyanide (HCN and CN ) and cyanide bound in the metal-
D1129 Terminology Relating to Water
cyanide complexes that are easily dissociated into free cyanide
D1193 Specification for Reagent Water
ions at the pH of the aquatic environment ranging from pH 6
D1293 Test Methods for pH of Water
to pH 8. The extent of HCN formation is less dependent on
D2036 Test Methods for Cyanides in Water
temperature than the pH; however, the temperature can be
D2777 Practice for Determination of Precision and Bias of
regulated if deemed necessary to further simulate the actual
Applicable Test Methods of Committee D19 on Water
aquatic environment.
D3370 Practices for Sampling Water from Closed Conduits
1.2 The aquatic free cyanide method is based on the same
D3856 Guide for Good Laboratory Practices in Laborato-
instrumentation and technology that is described in standard
ries Engaged in Sampling and Analysis of Water
test method D6888, but employs milder conditions (pH 6-8
D4841 Practice for Estimation of Holding Time for Water
buffer versus HCl in the reagent stream), and does not utilize
Samples Containing Organic and Inorganic Constituents
ligand displacement reagents.
D5847 Practice for Writing Quality Control Specifications
1.3 The aquatic free cyanide measured by this procedure
for Standard Test Methods for Water Analysis
should be similar to actual levels of HCN in the original
D6512 Practice for Interlaboratory Quantitation Estimate
aquatic environment. This in turn may give a reliable index of
D6696 Guide for Understanding Cyanide Species
toxicity to aquatic organisms.
D6888 Test Method for Available Cyanide with Ligand
1.4 This procedure is applicable over a range of approxi-
Displacement and Flow InjectionAnalysis (FIA) Utilizing
mately 2 to 500 µg/L (parts per billion) aquatic free cyanide.
Gas Diffusion Separation and Amperometric Detection
Sample dilution may increase cyanide recoveries depending on
E691 Practice for Conducting an Interlaboratory Study to
the cyanide speciation; therefore, it is not recommended to
Determine the Precision of a Test Method
dilute samples. Higher concentrations can be analyzed by
E1763 Guide for Interpretation and Use of Results from
increasing the range of calibration standards or with a lower
Interlaboratory Testing of Chemical Analysis Methods
injection volume. In accordance with Guide E1763 and Prac-
tice D6512 the lower scope limit was determined to be 9 µg/L
3. Terminology
for chlorinated gold leaching barren effluent water.
3.1 Definitions For definitions of terms used in this test
1.5 This standard does not purport to address all of the
method, refer to Terminology D1129 and Guide D6696.
safety concerns, if any, associated with its use. It is the
3.1.1 aquatic free cyanide—Sum of the free cyanide (HCN
responsibility of the user of this standard to establish appro-
-
and CN ) and cyanide bound in the metal-cyanide complexes
priate safety and health practices and determine the applica-
that are easily dissociated into free cyanide under the test
conditions described in this method.
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This test method is under the jurisdiction of ASTM Committee D19 on Water
2
and is the direct responsibility of Subcommittee D19.06 on Methods forAnalysis of For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Organic Substances in Water. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Feb. 1, 2006. Published February 2006. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D7237-06. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D7237 – 06
C = carrier (water),R=reagent buffer (variable: pH 6-8, 0.2M phosphate buffer), A = acceptor solution (0.1M NaOH), S = sample, P = peristaltic pump (flow rates in
mL/min),I=injectionvalve(200
...
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