United States         Office of Water             EPA-821-R-99-013
     Environmental Protection    (4303)                  August 1999
     Agency



&EPA   Method OIA-1677


         Available Cyanide by Flow


         Injection, Ligand Exchange,


         and Amperometry

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Method OIA-1677
                                  Acknowledgments

This method was  developed by Michael  Straka  of OI Analytical  in  cooperation with Emil
Milosavljevic and Ljiljana Solujic of the University of Nevada Reno Mackay School of Mines and guidance
from William A. Telliard of  the Engineering and  Analysis Division (BAD) within the U.S.
Environmental Protection Agency's (EPA's) Office of Science and Technology (OST). Additional
assistance in preparing the method was provided by DynCorp Information and Enterprise Technology
and Interface, Inc..
                                      Disclaimer

This Method has been reviewed and approved for publication by the Analytical Methods Staff within
EPA's Engineering and Analysis Division. Mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
Questions concerning this Method or its application should be addressed to:

W.A. Telliard
Engineering and Analysis Division (4303)
U.S. Environmental Protection Agency
401 M Street SW
Washington, DC 20460
Phone: 202/260-7120
Fax:  202/260-7185
                                                                               August 1999

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                                                                         Method OIA-1677
                                Table of Contents






    Introduction	 iv



    1.0           Scope and Application  	1



    2.0           Summary of Method	1



    3.0           Definitions  	2



    4.0           Contamination and Interferences  	2



    5.0           Safety	3



    6.0           Equipment and Supplies	4



    7.0           Reagents and Standards 	4



    8.0           Sample Collection, Preservation, and Storage  	8



    9.0           Quality Control 	10



    10.0         Calibration and Standardization  	16



    11.0         Procedure	17



    12.0         Data Analysis and Calculations	17



    13.0         Method Performance  	18



    14.0         Pollution Prevention and Waste Management	18



    15.0         References	19



    16.0         Tables 	20



    17.0         Glossary	21
August 1999

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Method OIA-1677
Introduction

Method OIA-1677 was developed by ALPKEM, a division of OI Analytical, in cooperation with the
University of Nevada Reno Mackay School of Mines, as a way to measure available cyanide without the
interference problems of the currently approved available cyanide methods. EPA proposed the use of Method
OIA-1677 on July 7, 1998 (63 FR 36809). EPA is approving the use of Method OIA-1677 for compliance
monitoring under Section 304(h) of the Clean Water Act.  Method OIA-1677 is  an additional test procedure
for measuring the same cyanide species as are measured by currently approved methods for cyanide amenable
to chlorination (CATC). In some matrices, CATC methods are subject to significant test interferences.
Method OIA-1677 has been added to the list of approved methods because it is more specific for available
cyanide, is more rapid, measures cyanide at lower concentrations, offers improved safety, reduces laboratory
waste, and is more precise and accurate than currently approved CATC methods.

Requests for additional copies of this Method should be directed to:

Attn: Catherine Anderson
ALPKEM
A Division of OI Analytical
PO Box 9010
College Station, TX 77842-9010
Phone: 409/690-1711
Fax: 409/690-0440

National Technical Information Service (NTIS)
5285 Port Royal Road
Springfield, V A 22161
Phone: 800/553-6847 or 703/605-6000
PB99-132011
                                                                                      August 1999

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                                                                                    Method OIA-1677
    Note:  This Method is performance based.  The laboratory is permitted to omit any step or modify any
    procedure provided that all performance requirements in this Method are met. The laboratory may
    not omit any quality control tests.  The terms "shall" and "must" define procedures required for
    producing reliable data at water quality criteria levels. The terms "should" and "may" indicate
    optional steps that may be modified or omitted if the laboratory can demonstrate that the modified
    method produces results equivalent or superior to results produced by this Method.	
August 1999

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                                 Method OIA-1677

        Available Cyanide by Flow Injection,  Ligand Exchange, and
                                   Amperometry


1.0    Scope and Application

1.1    This method is for determination of available cyanide in water and wastewater by flow
       injection, ligand exchange, and amperometric detection. The method is for use in EPA's
       data gathering and monitoring programs associated with the Clean Water Act, Resource
       Conservation and Recovery Act, Comprehensive Environmental Response, Compensation
       and Liability Act, and Safe Drinking Water Act.

1.2    Cyanide ion (GST), hydrogen cyanide in water (HCNaq), and the cyano-complexes of zinc,
       copper, cadmium, mercury, nickel, and silver may be determined by this method (see
       Section 17.2.1).

1.3    The presence of polysulfides may prove intractable  for application of this method.

1.4    The method detection limit (MDL) is 0.5  |ig/L and the minimum level (ML) is 2.0 |ig/L.
       The dynamic range is approximately 2.0 |ig/L (ppb) to 5.0 mg/L (ppm) cyanide ion using a
       200 fjL sample loop volume. Higher concentrations can be determined by dilution of the
       original sample or by reducing volume of the sample loop.

1.5    This method is for use by analysts experienced with flow injection equipment or under
       close supervision of such qualified persons.

1.6    The laboratory is permitted to modify the method to overcome interferences or to lower
       the cost of measurements, provided that all performance criteria in this method are met.
       Requirements for establishing method equivalency are given in Section 9.1.2.

2.0    Summary of Method

2.1    The analytical procedure employed for determination of available cyanide is divided into
       two parts: sample pretreatment and cyanide detection.  In the pretreatment step, ligand-
       exchange reagents are added at room temperature to 100 mL of a cyanide-containing
       sample. The ligand-exchange reagents form thermodynamically stable complexes with the
       transition metal ions listed in Section 1.2, resulting in the release of cyanide ion from the
       metal-cyano complexes.

       Cyanide detection is accomplished using a flow-injection analysis (FIA) system (Reference
       15.6).  A 200-//L aliquot of the pre-treated sample is injected into the flow injection
       manifold of the system.  The addition of hydrochloric acid converts cyanide ion to
       hydrogen cyanide (HCN) that passes under a gas diffusion membrane. The HCN diffuses
       through the membrane into an alkaline receiving solution where it is  converted back to
       cyanide ion. The cyanide ion is monitored amperometrically with a silver working
       electrode, silver/silver chloride reference electrode,  and platinum/stainless  steel counter

 August 1999                                  1

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 Method OIA-1677
        electrode, at an applied potential of zero volt. The current generated is proportional to
        the cyanide concentration present in the original sample.  Total analysis time is
        approximately two minutes.

2.2     The quality of the analysis is assured through reproducible calibration and testing of the
        FIA system.
2.3
A flow diagram of the FIA system is shown in Figure 1.
                        Acceptor
                         Carrier
                          Acid
                                 Pump
                                        Mixing
                                         Coll    Diffusion
                                                 Cell
                        Figure 1.  Row injection Manifold used in the quantification of
                                 cyanide in the pretreated sample. Carrier (0.1 M
                                 HCI); Acid (0.1 M HCI); Acceptor (0.1 M NaOH).
3.0    Definitions

        Definitions for terms used in this method are given in the glossary at the end of the
        method.

4.0    Interferences
4.1     Solvents, reagents, glassware, and other sample-processing hardware may yield artifacts
        that affect results.  Specific selection of reagents or purification of these reagents may be
        required.

4.2     All materials used in the analysis shall be demonstrated to be free from interferences under
        the conditions of analysis by running laboratory blanks as described in Section 9.4.

4.3     Glassware is cleaned by washing in hot water containing detergent, rinsing with tap and
        reagent water, and drying in an area free from interferences.

4.4     Interferences extracted from samples will vary considerably from source to source,
        depending upon the diversity of the site being sampled.

4.5     Sulfide is a positive interferent in this method (References 15.3 and 15.4), because an
        acidified sample containing sulfide liberates hydrogen sulfide that is passed through the

                                              2                                     August 1999

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                                                                        Method OIA-1677
       membrane and produces a signal at the silver electrode.  In addition, sulfide ion reacts with
       cyanide ion in solution to reduce its concentration over time. To overcome this
       interference, the sulfide ion must be precipitated with lead ion immediately upon sample
       collection. Sulfide ion and lead sulfide react with cyanide ion to form thiocyanate which is
       not detected in the analytical system.  Tests have shown (Reference 15.7) that if lead
       carbonate is used for sulfide precipitation, the supernate containing cyanide must be
       filtered immediately to avoid loss of cyanide through reaction with precipitated lead sulfide
       (Section 8.2.1).

4.6    Though not interferences, substances that react with cyanide should also be removed from
       samples at time of collection. These substances include water soluble aldehydes that form
       cyanohydrins and oxidants such as hypochlorite and sulfite. Water soluble aldehydes react
       with cyanide to form cyanohydrins that are not detected by the analytical system;
       hypochlorite and sulfite oxidize cyanide to non-volatile forms. Procedures for the removal
       of these substances are provided in Sections 8.2.2 and 8.2.3.

5.0    Safety

5.1    The toxicity or carcinogen!city of each compound or reagent used in this method has not
       been precisely determined; however, each chemical compound should be treated as a
       potential health hazard.  Exposure to these compounds should be reduced to the lowest
       possible level.

5.2    Cyanides and cyanide solutions

WARNING:   The cyanide  ion,  hydrocyanic  acid, all cyanide salts,  and  most
metal-cyanide complexes are extremely dangerous.  As  a contact poison,
cyanide need not  be  ingested  to produce  toxicity.    Also,  cyanide
solutions  produce  fatally toxic hydrogen  cyanide gas  when acidified.
For  these  reasons,  it  is mandatory  that  work with cyanide be carried out
in a well-ventilated hood by  properly trained personnel  wearing adequate
protective  equipment.

5.3    Sodium hydroxide solutions

CAUTION:   Considerable heat is generated  upon dissolution of sodium
hydroxide  in water.  It may be advisable  to cool the  container in an ice
bath when  preparing  sodium  hydroxide solutions.	

5.4    Unknown samples may contain high concentrations of volatile toxic compounds. Sample
       containers should be opened in a hood and handled with gloves to prevent exposure.

5.5    This method does not address all safety issues associated with its use.  The laboratory is
       responsible for maintaining a safe work environment and a current awareness file of
       OSHA regulations regarding the safe handling of the chemicals specified in this method.
       A reference file of material safety data sheets (MSDSs) should be available to all personnel
       involved in these analyses. Additional information on laboratory safety can be found in
       References 15.8 and  15.9.
 August 1999

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 Method OIA-1677
6.0    Equipment and Supplies
NOTE:   Brand names, suppliers,  and  part  numbers  are  for illustrative
purposes  only.   No endorsement is implied.   Equivalent performance may
be  achieved using apparatus  and materials  other  than those  specified
here,  but demonstration of equivalent performance that meets the
requirements of  this method  is the  responsibility of the laboratory.

6.1     Flow injection analysis (FIA) system—ALPKEM Model 3000 (Reference 15.5), or
       equivalent, consisting of the following:

       6.1.1  Injection valve capable of injecting 40 to 300 //L samples

       6.1.2  Gas diffusion manifold with a microporous Teflon® or polypropylene membrane

       6.1.3  Amperometric detection system with:

              6.1.3.1 Silver working electrode

              6.1.3.2 Ag/AgCl reference electrode

              6.1.3.3 Pt/stainless steel counter electrode

              6.1.3.4 Applied potential of 0.0 volt

6.2     Sampling equipment—Sample bottle, amber glass, 0.1-L, with polytetrafluoroethylene
       (PTFE)-lined cap.  Clean by washing with detergent and water, rinsing with two aliquots
       of reagent water, and drying by baking at 110 - 150 °C for one hour minimum.

6.3     Standard laboratory equipment including volumetric flasks, pipettes, syringes, etc. all
       cleaned, rinsed and dried per bottle cleaning procedure in Section 6.2.

7.0    Reagents  and Standards

7.1     Reagent water—Water in which cyanide and potentially interfering substances are not
       detected at the MDL of this method. It may be generated by any one of the methods listed
       below. Reagent water generated by these methods shall be tested for purity utilizing the
       procedure in Section 11.

       7.1.1  Activated carbon—Pass distilled or deionized water through an activated carbon
              bed (Calgon Filtrasorb-300 or equivalent).

       7.1.2  Water purifier—Pass distilled or deionized water through a purifier (Millipore
              Super Q, or equivalent).

7.2     Sodium hydroxide—ACS reagent grade.

7.3     Potassium cyanide—ACS reagent grade.

                                          4                                  August 1999

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                                                                            Method OIA-1677
7.4     Mercury (II) cyanide, >99% purity—Aldrich Chemical Company Catalog No. 208140, or
        equivalent.

7.5     Potassium nickel (II) cyanide—Aldrich Chemical Company Catalog No. 415154, or
        equivalent.

7.6     Silver nitrate—ACS reagent grade. Aldrich Chemical Company Catalog No. 209139, or
        equivalent.

7.7     Hydrochloric acid—approximately 37%, ACS reagent grade.

7.8     Preparation of stock solutions. Observe the warning in Section 5.2.

        7.8.1   Silver nitrate solution, 0.0192 N—Weigh 3.27 g of AgNO3  into a 1-L volumetric
               flask and bring to the mark with reagent water.

        7.8.2   Rhodanine solution, 0.2 mg/mL in acetone—Weigh 20 mg of p-
               dimethylaminobenzalrhodanine (Aldrich Chemical Co. Catalog No. 114588, or
               equivalent) in a 100-mL volumetric flask and dilute to the mark with acetone.

        7.8.3   Potassium cyanide stock solution, 1000 mg/L

               7.8.3.1   Dissolve approximately 2 g (approximately 20 pellets) of sodium
                       hydroxide in approximately 500 mL of reagent water contained in a one
                       liter volumetric flask.  Observe the caution in Section 5.3. Add 2.51 g of
                       potassium cyanide (Aldrich Chemical Co. Catalog No. 207810, or
                       equivalent), dilute to one liter with reagent water,  and mix well.  Store
                       KCN solution in an amber glass container at 0-4°C.

               7.8.3.2  Standardize the KCN solution (Section 7.8.3.1) by adding 0.5 mL of
                       rhodanine solution (Section 7.8.2) to 25 mL  of KCN solution and
                       titrating with AgNO3 solution (Section 7.8.1) until the color changes
                       from canary yellow to a salmon hue. Based on the determined KCN
                       concentration, dilute the KCN solution to an appropriate volume so the
                       final concentration is 1.00 g/L, using the following equation:
 August 1999

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 Method OIA-1677
                                       EQUATION 1


                                       v = 1 g/i x l
                       where:
                       x=concentration of KCN solution determined from titrations
	v=volume of KCN solution needed to prepare 1 L of 1 g/L KCN solution

                       If the concentration is not  1.00 g/L, correct the intermediate and working
                       calibration concentrations accordingly.

        7.8.4   1M sodium hydroxide—Dissolve 40 g of sodium hydroxide pellets in
               approximately 500 mL of reagent water in a 1-liter volumetric flask, observing the
               caution in Section 5.3.  Dilute to one liter with reagent water. Store in an amber
               bottle at room temperature.

7.9     Secondary standards.

        7.9.1   Cyanide, 100 mg/L—Dilute 100.0 mL of cyanide stock solution (Section 7.8.3.2)
               and 10 mL of 1M sodium hydroxide (Section  7.8.4) to one liter with reagent water
               (Section 7.1). Store in an amber glass bottle at 0-4°C.

        7.9.2   Cyanide, 10 mg/L—Dilute 10.0 mL of cyanide stock solution and 10 mL of 1M
               sodium hydroxide to one liter with reagent water.  Store in an amber glass bottle at
               0-4°C.

        7.9.3   Cyanide, 1 mg/L—Dilute 1.0 mL of cyanide stock solution and  1 mL of 1M
               sodium hydroxide to one liter with reagent water.  Store in an amber glass bottle at
               0-4°C.

        7.9.4   Cyanide working calibration standard solutions (2 - 5000 |ig/L as
               cyanide)—Working calibration standards may be prepared to cover the desired
               calibration range by adding the appropriate volumes of secondary standards
               (Sections 7.9.1, 7.9.2, 7.9.3) to 100  mL volumetric flasks that contain 40 mL of
               reagent water (Section 7.1) and 1 mL of 1M sodium hydroxide  (Section 7.8.4).
               Dilute the solutions to  100 mL with reagent water.  Prepare working calibration
               standards daily. The following table provides the quantity of secondary standard
               necessary to  prepare working standards of the specified concentration.
                                                                                 August 1999

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                                                                             Method OIA-1677
Working
Calibration
Standard
Concentration
(Mg/L)
0.000
2.0
5.0
10.0
50.0
100
200
500
1000
3000
5000
Secondary Standard Solution Volume
Secondary Standard
Concentration
(Section 7.8.3)
1 mg/L

0.200
0.500
1.00
5.00
10.0
20.0
50.0



Secondary Standard
Concentration
(Section 7.8.2)
10 mg/L


0.050
0.100
0.500
1.00
2.00
5.00
10.0
30.0
50.0
Secondary Standard
Concentration
(Section 7.8.1)
100 mg/L




0.050
0.100
0.200
0.500
1.00
3.00
5.00
        If desired, the laboratory may extend the analytical working range by using  standards that
        cover more than one calibration range, so long as the requirements of Section 10.3 are
        met.

7.10    Sample Preservation Reagents

        7.10.1 The presence of sulfide may result in the conversion of cyanide to thiocyanate.
              While lead acetate test paper has been recommended for determining the presence
              of sulfide in samples, the test is generally unreliable and is typically not usable for
              sulfide concentrations below approximately 1 ppm.  The use  of lead carbonate
              (Aldrich Chemical Co. Catalog No.  336378, or equivalent), followed by immediate
              filtration of the sample is required whenever sulfide ion is present. If the presence
              of sulfide is suspected but not verifiable from the use of lead acetate test paper,
              two samples may be collected,  one without lead carbonate addition and  another
              with lead carbonate addition followed by immediate filtration. Analyze both
              samples.  If sulfide is present, the preserved sample should contain higher levels of
              cyanide than the unpreserved sample. Lead acetate test paper may be used, but
              should be tested for minimum level  of sulfide detection by spiking reagent water
              aliquots with decreasing levels of sulfide and determining the lowest level of
              sulfide detection attainable. The spiked samples are tested with lead acetate test
              paper moistened with acetate buffer solution.  The buffer solution is prepared by
 August 1999

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 Method OIA-1677
              dissolving 146 g anhydrous sodium acetate, or 243 g sodium acetate trihydrate in
              400 mL of reagent water, followed by addition of 480 g concentrated acetic acid.
              Dilute the solution to 1 L with reagent water. Each new batch of test paper and/or
              acetate buffer should be tested to determine the lowest level of sulfide ion
              detection prior to use.

        7.10.2 Ethylenediamine solution—In a 100 mL volumetric flask, dilute 3.5 mL
              pharmaceutical-grade anhydrous ethyl enediamine (Aldrich Chemical Co. Catalog
              No. 240729, or equivalent) with reagent water.

        7.10.3 Ascorbic acid—Crystals—Aldrich Chemical Co. Catalog No. 268550, or
              equivalent.

7.11    FIA Reagents.

        7.11.1 Carrier and acid reagent (0.1M hydrochloric acid)—Dilute 8 mL of concentrated
              hydrochloric acid to one liter with reagent water.

        7.11.2 Acceptor reagent (0.1M sodium hydroxide)—Dilute 100 mL of sodium hydroxide
              solution (Section 7.8.4) to 1000 mL with reagent water.

        7.11.3 Ligand-exchange reagent A-ALPKEM part number A001416, or equivalent.

        7.11.4 Ligand-exchange reagent B-ALPKEM part number A001417, or equivalent.

7.12    Quality control solutions

        7.12.1 Mercury (II) cyanide stock solution (1000 mg/L as cyanide)—Weigh 0.486 g of
              mercury (II) cyanide (Section 7.4) in a 100-mL volumetric flask. Add 10-20 mL
              of reagent water and 1 mL of 1M sodium hydroxide solution (Section 7.8.4).
              Swirl to mix. Dilute to the mark with reagent water.

        7.12.2 Laboratory control sample (LCS)—Place 0.20 mL of the mercury (II) cyanide
              stock solution (Section 7.12.1) in a 100-mL volumetric flask and dilute to the
              mark with reagent water to provide a final cyanide concentration of 2.00 mg/L.

8.0    Sample Collection, Preservation, and Storage

8.1     Sample collection and preservation—Samples are collected using manual (grab)
        techniques and are preserved immediately upon collection.

        8.1.1  Grab  sampling—Collect samples in amber glass bottles with PTFE-lined caps
              cleaned according to the procedure in Section 6.2. Immediately after collection,
              preserve the sample using any or all of the preservation techniques (Section  8.2),
              followed by adjustment of the sample pH to > 12 by addition of 1M sodium
              hydroxide and refrigeration at 0-4°C.
                                                                                August 1999

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                                                                             Method OIA-1677
        8.1.2   Compositing—Compositing is performed by combining aliquots of grab samples
               only. Automated compositing equipment may not be used because cyanide may
               react or degrade during the sampling period.  Preserve and refrigerate each grab
               sample immediately after collection (Sections 8.1.1 and 8.2) until compositing.

        8.1.3   Shipment—If the sample will be shipped by common carrier or mail, limit the pH
               to a range of 12.0 - 12.3.  (See the footnote to 40 CFR 136.3(e), Table II, for the
               column headed "Preservation.")

8.2     Preservation techniques

        8.2.1   Samples containing sulfide ion

               8.2.1.1  Test the  sample with lead acetate test paper (Section 7.10.1) to
                       determine the presence or absence of sulfide ion. If sulfide ion is present,
                       the sample must be treated immediately (within  15 minutes of collection)
                       with sufficient solid lead carbonate (Section 7.10.1) to  remove sulfide (as
                       evidenced by the lead acetate test paper), and immediately filtered into
                       another sample bottle to remove precipitated lead sulfide.

               8.2.1.2  If sulfide ion is suspected to be present, but its presence is not detected
                       by the lead acetate paper test, two samples should be collected.  One is
                       treated for the presence of sulfide and immediately filtered, while the
                       second is not treated for sulfide.  Both samples must be analyzed. (Tests
                       conducted prior to the interlaboratory validation of this method showed
                       significant and rapid losses of cyanides when lead sulfide was allowed to
                       remain in contact with the sample during holding times of three days or
                       less.  As a result, the immediate filtration of samples preserved with lead
                       carbonate is essential (Reference 15.6)).

               8.2.1.3  If the sample contains particulate matter that would be removed upon
                       filtration, the sample must be filtered prior to treatment with lead
                       carbonate to assure that cyanides associated with the particulate matter
                       are included in the measurement. The collected particulate matter must
                       be saved and the filtrate treated using the sulfide removal procedure
                       above (Section 8.2.1.1).  The collected particulate and treated filtrate
                       must be recombined and homogenized, and then sent to the laboratory
                       for analysis.

        8.2.2   Samples containing water soluble aldehydes—Treat samples containing or
               suspected to contain formaldehyde, acetaldehyde, or other water soluble aldehydes
               with 20 mL of 3.5% ethylenediamine  solution (Section 7.10.2) per liter of sample.

        8.2.3   Samples known or suspected to contain chlorine, hypochlorite, and/or
               sulfite—Treat with 0.6 g of ascorbic acid (Section 7.10.3) per liter of sample.
               EPA Method 330.4 or 330.5 may be used  for the measurement of residual chlorine
               (Reference  15.1).

 August 1999                                    9

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 Method OIA-1677
8.3     Sample holding time—Maximum holding time for samples preserved as above is 14 days.
        Unpreserved samples must be analyzed within 24 hours, or sooner if a change in cyanide
        concentration will occur.  (See the footnotes to Table II at 40 CFR 136.3(e).)

9.0     Quality Control

9.1     Each laboratory that uses this method is required to operate a formal quality assurance
        program (Reference 15.9).  The minimum requirements of this program consist of an
        initial demonstration of laboratory capability, and the periodic analysis of LCSs and
        MS/MSDs as a continuing check on performance.  Laboratory performance is compared
        to established performance criteria to determine if the results of the analyses meet the
        performance characteristics of the method.

        9.1.1  The laboratory shall make an initial  demonstration of the ability to generate
              acceptable precision and accuracy with this  method.  This ability is established as
              described in Section 9.2.

        9.1.2  In recognition of advances that are occurring in analytical technology, and to allow
              the laboratory to overcome sample matrix interferences, the laboratory is permitted
              certain options to improve performance or lower the costs of measurements.
              Alternate determinative techniques, such as the substitution of spectroscopic or
              immuno-assay techniques, and changes that degrade method performance, are not
              allowed.  If an analytical technique other than the techniques specified in this
              method is used, then that technique  must have a specificity equal to or better than
              the specificity of the techniques in this method for the analytes of interest.

              9.1.2.1  Each time a modification is made  to this method, the laboratory is
                       required to repeat the procedure in Section 9.2.  If the detection limit of
                       the method will be affected by the change, the laboratory must
                       demonstrate that the MDL is equal to or less than the MDL in Section
                        1.4 or one-third the regulatory compliance level, whichever is greater. If
                       calibration will be affected by the  change, the laboratory must recalibrate
                       the instrument per Section 10.3.

              9.1.2.2  The laboratory is required to maintain records of modifications made to
                       this method. These records include the information in this subsection, at
                       a minimum.

                       9.1.2.2.1    The names, titles, addresses, and telephone numbers of the
                                   analyst(s) who performed the analyses and modification, and
                                   of the quality control officer who witnessed and will verify
                                   the analyses and modification.

                       9.1.2.2.2    A narrative stating the reason(s) for the modification.

                       9.1.2.2.3    Results from all quality control (QC) tests comparing the
                                   modified method to this method including:

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                                                                             Method OIA-1677
                                  (a)    calibration (Section 10.3)
                                  (b)    calibration verification (Section 9.5)
                                  (c)    initial precision and recovery (Section 9.2)
                                  (d)    analysis of blanks (Section 9.4)
                                  (e)    laboratory control sample (Section 9.6)
                                  (f)    matrix spike and matrix spike duplicate (Section 9.3)
                                  (g)    MDL (Section 1.4)

                       9.1.2.2.4   Data that will allow an independent reviewer to validate each
                                  determination by tracing the instrument output (peak height,
                                  area, or other signal) to the final result.  These data are to
                                  include:

                                  (a)    sample numbers and other identifiers
                                  (b)    analysis dates and times
                                  (c)    analysis sequence/run chronology
                                  (d)    sample weight or volume
                                  (e)    sample volume prior to each cleanup step, if
                                         applicable
                                  (f)    sample volume after each cleanup step, if applicable
                                  (g)    final sample volume prior to injection (Sections 10
                                         and 11)
                                  (h)    injection volume  (Sections 10 and 11)
                                  (i)    dilution data, differentiating between dilution of a
                                         sample or modified sample (Sections 10 and 11)
                                  (j)    instrument and operating conditions
                                  (k)    other operating conditions  (temperature, flow rates,
                                         etc.)
                                  (1)    detector (operating condition, etc.)
                                  (m)    printer tapes, disks, and other recording of raw data
                                  (n)    quantitation reports, data system outputs, and other
                                         data necessary to link raw data to the results reported

       9.1.3  Analyses of matrix spike and matrix spike duplicate samples are required to
              demonstrate method accuracy  and precision and to monitor matrix interferences
              (interferences caused by the sample matrix). The procedure and QC criteria for
              spiking are described in Section 9.3.

       9.1.4  Analyses of blanks are required to demonstrate freedom from contamination and
              that the compounds of interest and interfering compounds have not been carried
              over from a previous analysis.  The procedures and criteria for analysis of a blank
              are described in Section 9.4.

       9.1.5  The laboratory  shall, on an ongoing basis, demonstrate through the analysis of the
              LCS (Section 7.12.2) that  the analysis system is in control. This  procedure is
              described in Section 9.6.
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 Method OIA-1677
        9.1.6  The laboratory should maintain records to define the quality of data that is
              generated.  Development of accuracy statements is described in Sections 9.3.8 and
              9.6.3.

        9.1.7  Accompanying QC for the determination of cyanide is required per analytical
              batch.  An analytical batch is a set of samples analyzed at the same time, to a
              maximum of 10 samples. Each analytical batch of 10 or fewer samples must be
              accompanied by a laboratory blank (Section 9.4),  an LCS (Section 9.6), and a
              matrix spike and matrix spike duplicate (MS/MSD, Section 9.3), resulting in a
              minimum of five analyses (1 sample, 1 blank, 1 LCS, 1 MS, and 1  MSD) and a
              maximum of 14 analyses (10 samples, 1 blank, 1 LCS, 1 MS, and  1 MSD) in the
              batch.  If greater than  10 samples are analyzed at one time, the samples must be
              separated into analytical batches of 10 or fewer samples.

9.2     Initial demonstration of laboratory capability

        9.2.1  Method Detection Limit (MDL)—To establish the ability to detect cyanide at low
              levels, the laboratory shall determine the MDL per the procedure in 40 CFR Part
              136, Appendix B (Reference 15.4) using the apparatus, reagents, and standards
              that will be used in the practice of this method.  An MDL less than or equal  to the
              MDL listed in Section 1.4 must be achieved prior to practice of this method.

        9.2.2  Initial Precision and Recovery  (IPR)—To establish the ability to generate
              acceptable precision and accuracy, the laboratory shall perform the following
              operations:

              9.2.2.1   Analyze four samples of the LCS (Section 7.12.2) according to the
                       procedure beginning in Section 10.

              9.2.2.2  Using the results of the set of four analyses, compute the average percent
                       recovery (x) and the standard deviation of the percent recovery (s) for
                       cyanide.  Use Equation 2 for calculation of the standard deviation of the
                       percent recovery.

                                       EQUATION 2
                                    E
                                         n - 1
                       where:
                       n = Number of samples
                       x = Percent recovery in each sample
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                                                                             Method OIA-1677
        9.2.3   Compare s and x with the acceptance criteria specified in Table 1.  If s exceeds the
               precision limit or x falls outside the range for recovery, system performance is
               unacceptable and the problem must be found and corrected before analyses can
               begin.

9.3     Matrix spike/matrix spike duplicate (MS/MSD)—The laboratory shall spike, in duplicate,
        a minimum of 10 percent of all samples (one sample in duplicate in each batch often
        samples) from a given discharge.

        9.3.1   The concentration of the spike in the sample shall be determined as follows:

               9.3.1.1   If, as in compliance monitoring, the concentration of cyanide in the
                        sample is being checked against a regulatory concentration limit, the
                        spiking level shall be at that limit or at 1 to 5 times higher than the
                        background concentration of the sample (determined in Section 9.3.2),
                        whichever concentration is higher.

               9.3.1.2   If the concentration of cyanide in a sample is not being checked against a
                        limit, the  spike shall be at the concentration of the LCS or at 1 to 5 times
                        higher than the background concentration, whichever concentration is
                        higher.

        9.3.2   Analyze one sample aliquot out of each set  often samples from each discharge
               according to the procedure beginning in Section 11 to determine the background
               concentration (B) of cyanide.

               9.3.2.1   Spike this sample with the amount of mercury (II) cyanide stock solution
                        (Section 7.12.1) necessary to  produce a cyanide concentration in the
                        sample of 2 mg/L. If necessary, prepare another stock solution
                        appropriate to produce a level in the sample at the regulatory compliance
                        limit or at 1 to 5 times the background concentration (per Section 9.3.1).

               9.3.2.2   Spike two additional sample aliquots with the spiking solution and
                        analyze these aliquots to determine the concentration after spiking (A).

        9.3.3   Calculate the percent recovery of cyanide in each aliquot using Equation 3.
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Method OIA-1677
                                      EQUATION 3

                                           100  (A - B)
                                      P  =
                      where:
                      P = Percent recovery
                      A = Measured concentration of cyanide after spiking
                      B = Measured background concentration of cyanide
                      T = True concentration of the spike	
       9.3.4   Compare the recovery to the QC acceptance criteria in Table 1.  If recovery is
              outside of the acceptance criteria, and the recovery of the LCS in the ongoing
              precision and recovery test (Section 9.6) for the analytical batch is within the
              acceptance criteria, an interference is present. In this case, the result may not be
              reported for regulatory compliance purposes.

       9.3.5   If the results of both the MS/MSD and the LCS test fail the acceptance criteria, the
              analytical system is judged to be out of control.  In this case, the problem shall be
              identified and corrected, and the analytical batch reanalyzed.

       9.3.6   Calculate the relative percent difference (RPD) between the two spiked sample
              results (Section 9.3, not between the two percent recoveries) using Equation 4.

                                      EQUATION 4
                                         £>, - D9
                                RPD =	  x  100
                                        (D  +  D}/2
                      where:
                      RPD = Relative percent difference
                      Dj = Concentration of cyanide in the spiked sample
      	D2 = Concentration of cyanide in the spiked duplicate sample	

       9.3.7   Compare the precision to the RPD criteria in Table 1.  If the RPD is greater than
              the acceptance criteria, the analytical system is judged to be out of control, and the
              problem must be immediately identified and corrected, and the analytical batch
              reanalyzed.

       9.3.8   As part of the QC program for the laboratory, method precision and accuracy for
              samples should be assessed and records should be maintained. After the analysis
              of five spiked samples in which the recovery passes the test in Section 9.3.4,
              compute the average percent recovery  (Pa) and the standard deviation of the
              percent recovery (sp). Express the accuracy assessment as a percent recovery

                                           14                                    August 1999

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                                                                              Method OIA-1677
               interval from Pa - 2sp to Pa + 2sp. For example, if Pa = 90% and sp = 10% for five
               analyses, the accuracy interval is expressed as 70 - 110%. Update the accuracy
               assessment on a regular basis (e.g., after each five to ten new accuracy
               measurements).

9.4     Laboratory blanks—Laboratory reagent water blanks are analyzed to demonstrate
        freedom from contamination.

        9.4.1   Analyze a reagent water blank initially (i.e., with the tests in Section 9.2) and with
               each analytical batch.  The blank must be subjected to the same procedural steps as
               a sample.

        9.4.2   If cyanide is detected in the blank at a concentration greater than the ML, analysis
               of samples is halted until the source of contamination is eliminated and a blank
               shows no evidence of contamination.

9.5     Calibration verification—Verify calibration of the analytical equipment before and after
        each analytical batch of 14 or fewer measurements.  (The 14 measurements will normally
        be 10  samples, 1 reagent blank, 1 LCS,  1 MS, and 1 MSD). Verification is accomplished
        by analyzing the mid-range calibration standard and verifying that it is within the QC
        acceptance criteria for recovery in Table 1.  (The concentration of the calibration
        verification depends on the calibration range being used.) Failure to verify calibration
        within the acceptance criteria requires recalibration of the analysis system.

9.6     Laboratory control sample (LCS)—To demonstrate that the analytical system is in control,
        and acceptable precision and accuracy is being maintained with each analytical batch, the
        laboratory shall perform the following operations.

        9.6.1   Analyze a LCS  (Section 7.12.2) with each analytical batch according to the
               procedure in Section 10.

        9.6.2   If the results for the LCS are within the acceptance criteria specified in Table 1,
               analysis of the batch may continue.  If, however, the concentration is not within
               this range, the analytical process is not in control.  In this event, correct the
               problem, repeat the LCS test, and reanalyze the batch.

        9.6.3   The laboratory should add results that pass the specification in Section 9.6.2 to
               IPR and previous LCS  data and update QC charts to form a graphic representation
               of continued laboratory performance. The laboratory  should  also develop a
               statement of laboratory data quality for cyanide by calculating the average percent
               recovery (R) and the standard deviation of the percent recovery (sr). Express the
               accuracy as a recovery  interval from R - 2sr to R + 2sr. For example, if R =  95%
               and sr = 5%, the accuracy is 85% to 105%.

9.7     Reference Sample—To demonstrate that the analytical system is in control, the laboratory
        should periodically test an external reference sample, such as  a Standard Reference
        Material (SRM) if an SRM is available from the National Institutes of Standards and

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 Method OIA-1677
        Technology (NIST). The reference sample should be analyzed quarterly, at a minimum.
        Corrective action should be taken if the measured concentration significantly differs from
        the stated concentration.

10.0   Calibration and Standardization

This section describes the procedure to calibrate and standardize the FIA system prior to cyanide
determination.

10.1    Instrument setup

        10.1.1  Set up the FIA system and establish initial operating conditions necessary for
               determination of cyanide. If the FIA system is computerized, establish a method
               for multi-point calibration and for determining the cyanide concentration in each
               sample.

        10.1.2  Verify that the reagents are flowing smoothly through the FIA system and that the
               flow cell is purged of air bubbles.

10.2    Instrument Stabilization

        10.2.1  Load a 10 mg/L KCN standard (Section 7.8.3) into the sampling valve and inject
               into the FIA system.

        10.2.2  Continue to inject 10 mg/L KCN standards  until 3 successive peak height or area
               results are within 2% RSD, indicating that the electrode system is stabilized.

        10.2.3  Following stabilization, inject the highest concentration calibration standard until 3
               successive peak height or area results are within 2% RSD indicating stabilization at
               the top of the calibration range.

10.3    External standard calibration

        10.3.1  Inject each of a minimum of 3 calibration standards. One of the standards should
               be at the minimum level (ML) unless measurements are to be made at higher
               levels.  The other concentrations should correspond to the expected range of
               concentrations found in samples or should define the working range of the FIA
               system.

        10.3.2  Using injections of a constant volume, analyze each calibration standard according
               to Section 11 and record peak height or area responses against the concentration.
               The results can be used to prepare  a calibration curve.  Alternatively, if the ratio of
               response to amount injected (calibration factor) is constant over the working range
               (<10% RSD), linearity through the origin can be assumed and the averaged
               calibration factor (area/concentration) can be used in place of a calibration curve.
                                            16                                    August 1999

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                                                                     Method OIA-1677
11.0   Procedure

This section describes the procedure for determination of available cyanide using the FIA system.

11.1    Analysis of standards, samples, and blanks

       11.1.1 Ligand-exchange reagent treatment of standards, samples, and blanks.

       11.1.2 To 100-mL of cyanide-containing sample (or standard or blank) at pH of
             approximately 12, add 100 jiL of ligand-exchange reagent Part B (Section 7.11.5),
             SOjiL of ligand-exchange reagent Part A (Section 7.11.4), and mix thoroughly.
             Load the sample, standard, or blank into the sample loop.
NOTE:   The ligand-exchange reagents,  when  added to  100 mL of  sample at
the  specified volume, will liberate cyanide  from metal complexes of
intermediate stability  up to 5 mg/L cyanide  ion.  If  higher
concentrations  are anticipated,  add additional ligand-exchange  reagent,
as appropriate,  or dilute the sample.  The ligand-exchange reagents have
an approximate  lifetime of 6 months after  opening.  The reagents should
be stored in a  refrigerator at 4°C.   Samples  should be analyzed within  2
hours  of adding the ligand-exchange reagents.   The  reagents should
always be used  in solutions similar to cyanide samples (pH 12  adjusted).
It is  recommended that  the ligands  be checked monthly.  This  can be done
by preparing pH 12 adjusted 2 mg/1  solutions  of mercury(II) cyanide
(Section 7.4) and of potassium nickel(II)  cyanide  (Section 7.5).  Add
ligand-exchange reagent B to the  mercury(II)  standard and ligand-
exchange reagent A to the potassium nickel(II) cyanide standard and
confirm cyanide recovery.	


       11.1.3 Inject the sample and begin data collection. When data collection is complete,
             analyze the next sample, standard or blank in the batch until analyses of all samples
             in the batch are completed.


12.0  Data Analysis and Calculations


12.1    Calculate the concentration of material in the sample, standard or blank from the peak
       height or area using the calibration curve or calibration factor determined in Section 10.3.


12.2    Reporting


       12.2.1 Samples—Report results to three significant figures for cyanide concentrations
             found above the ML (Section 1.4) in all samples. Report results below the ML as
             <2 £ig/L, or as  required by the permitting authority or permit.


       12.2.2 Blanks—Report results to three significant figures for cyanide concentrations
             found above the MDL (Section 1.4). Do not report results below the MDL unless
             required by the permitting authority or in the permit.
 August 1999                                17

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 Method OIA-1677
13.0   Method  Performance

13.1    Method detection limit (MDL)—MDLs from nine laboratories were pooled to develop the
        MDL of 0.5 //g/L given in Section 1.4 (Reference 15.12).

13.2    Data obtained from single laboratory testing of the method are summarized in Table 2 and
        show recoveries and reproducibility for "free" forms of cyanide, including the recovery
        and reproducibility of silver, nickel, and mercury cyanide species.  Determination of these
        species tends to be problematic with other methods for the determination of available
        cyanide.  As it is the case with other methods used for available cyanide, iron cyanide
        species were not recovered and recoveries for gold and cobalt species were zero or very
        low.  The complete results from the single laboratory study are available in the Report of
        the Draft OIA Method 1677 Single Laboratory Validation Study (Reference 15.11).

13.3    Listed in Table 1 are the QC acceptance criteria  developed from an interlaboratory
        validation study of this method.  This study was  conducted following procedures specified
        in the Guide to Method Flexibility and Approval of EPA Water Methods (Reference
        15.10). In this study, a total of nine laboratories performed analyses for various water
        matrices. Table 3 shows a summary of the interlaboratory results which include the
        accuracy and precision data as % recoveries and relative  standard deviations.  In addition
        to spikes of easily dissociable cyanides, some samples contained known amounts of
        cyanides that are not recoverable (e.g., Pt and Fe complexes) and thiocyanate was spiked
        to one sample to investigate the potential  for interference. The complete study results are
        available in the Report of the Draft OIA Method 1677 Interlaboratory Validation Study
        (Reference 15.12).

14.0   Pollution  Prevention and Waste Management

14.1    The laboratory is responsible for complying with all Federal, State, and local regulations
        governing waste management, particularly hazardous waste identification rules and land
        disposal restrictions, and for protecting the air, water, and land by minimizing and
        controlling all releases from fume hoods and bench operations. Compliance with all
        sewage discharge permits and regulations is also required. An overview of requirements
        can be found in Environmental Management Guide for Small Laboratories (EPA 233-B-
        98-001).

14.2    Samples containing cyanide, certain metals, and  acids at a pH of less than 2 are hazardous
        and must be treated before being poured down a drain or must be handled as hazardous
        waste.

14.3    For further information on waste management, consult Less is Better: Laboratory
        Chemical Management for Waste Reduction., Reference  15.8.
                                           18                                   August 1999

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                                                                         Method OIA-1677
15.0  References

15.1    Environmental Monitoring Systems Laboratory. EPA Method 335.1.  In: Methods for the
       Chemical Analysis of Water and Wastes (EPA/600/4-79-020). Environmental Protection
       Agency, Cincinnati, Ohio. Revised March 1983.

15.2    American Public Health Association, American Waterworks Association, Water Pollution
       Control Board.  Methods Section 4500-CN in Standard Methods for the Examination of
       Water and Wastewater,  19th Edition. American Public Health Association, Washington,
       DC, 1995.

15.3    Ingersol,  D.; Harris, W.R.; Bomberger, D.C.; Coulson, D.M. Development and
       Evaluation Procedures for the Analysis of Simple Cyanides, Total Cyanides, and
       Thiocyanate in Water and Waste Water (EPA-600/4-83-054), 1983.

15.4    Code of Federal Regulations, Title 40, Part 136, Appendix B. U.S.  Government Printing
       Office, Washington, D.C., 1994.

15.5    ALPKEM CNSolution Model 3000 Manual. Available from ALPKEM / OI Analytical,
       Box 9010, College Station, TX 77842-9010.

15.6    Milosavljevic, E.B.; Solujic, L.; Hendrix, J.L.  Environmental Science and Technology,
       Vol. 29, No. 2, 1995, pp 426-430.  Rapid Distillationless "Free Cyanide" Determination
       by a Flow Injection Ligand Exchange Method.

15.7    Wilmont, J.C.; Solujic, L.; Milosavljevic, E. B.; Hendrix, J.L.; Reader, W.S.  Analyst, June
       1996, Vol. 121, pp 799-801.  Formation of Thiocyanate During Removal of Sulfide as
       Lead Sulfide Prior to Cyanide Determination.

15.8    Less is Better: Laboratory Chemical Management for Waste Reduction. Available from
       the American Chemical  Society, Department of Government Regulations and Science
       Policy, 1155 16th Street, NW, Washington, DC  20036.

15.9    Handbook for Analytical Quality Control in Water and Wastewater Laboratories (EPA-
       600/4-79-019), USEPA, NERL, Cincinnati, Ohio 45268 (March 1979).

15.10  Guide to Method Flexibility and Approval of EPA  Water Methods, December, 1996,
       (EPA-821-D-96-004). Available from the National Technical Information Service (PB97-
       117766).

15.11  Report of the Draft OlA Method 1677 Single Laboratory Validation Study, November
       1996. Available from ALPKEM / OI Analytical, Box 9010, College Station, TX 77842-
       9010.

15.12  Report of the Draft OIA Method 1677 Inter laboratory Validation Study, March 1997.
       Available from ALPKEM / OI Analytical, Box 9010, College Station, TX 77842-9010.
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 Method OIA-1677
16.0   Tables
Table 1.  Quality Control Acceptance Criteria
Criterion
Initial Precision and Recovery
Ongoing Precision and Recovery
(Laboratory Control Sample)
Calibration Verification
Matrix Spike/Matrix Spike
Duplicate
Required Recovery Range
(%)
92 - 122
82- 132
86- 118
82- 130
Precision
<5.1%RSD
N/A
N/A
<11%RPD
Table 2. Species-Dependent Cyanide Recoveries Using Draft Method 1677(1)
Species
[Zn(CN)4f
[Cd(CN)4f
[Cu(CN)4f
[Ag(CN)4f
[Ni(CN)4f
[Hg(CN)4f
Hg(CN)2
[Fe(CN)4]4-
[Fe(CN)6]3-
[Au(CN)2]-
[Co(CN)6f
0.20 |ig/mL CN-
97.4 (0.7)
100.0(0.8)
100.9(1.3)
101.8(0.9)
104.3 (0.2)
100.0 (0.6)
103.4(0.4)
0.0
0.0
1.3(2)(0.0)
2.9(2) (0.0)
2.00 |ig/mL CN-
98.5 (0.7)
100.0 (0.2)
99.0 (0.6)
100.0(0.5)
103.0(0.5)
99.0 (0.3)
98.0(0.3)
0.0
0.0
0.0
2.0(2) (0.0)
1  Values are % recoveries; numbers in parentheses are percent relative standard deviations.
2  Commercial product contains some free cyanide.
                                           20
August 1999

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                                                                          Method OIA-1677
Table 3.  Cyanide Recoveries From Various Aqueous Matrices
Sample
Reagent water w/O.OlM
NaOH
POTW secondary effluent
Petroleum Refinery
Secondary Effluent
Coke Plant Secondary
Effluent
Rolling Mill Direct Filter
Effluent
Metals Finishing Indirect
Primary Effluent
Reagent water w/O.OlM
NaOH
Reagent water w/O.OlM
NaOH
Mining Tailing Pond Effluent
Sample CN
Concentration
O^g/L
3.0 ng/L
9.9 j^g/L
14.0 j^g/L
4.0 j^g/L
l.Ojjg/L
O^g/L
O^g/L
842 j^g/L
Added CN(1)
Concentration
lOO^ig/LasKCN
lOO^ig/LasKCN;
2 mg/L as [Pt(CN)6]4-
2 mg/L as KCN;
5 mg/L as [Fe(CN)6]4-
50 ng/L as KCN
none
200 ng/L as KCN;
2 mg/L as KSCN
200 ng/L as KCN
10 mg/L as KCN;
10 mg/L as [Pt(CN)6]4-
4 mg/L as KCN
Average %
Recovery
108
102
87
95
80
92
101
103
98
% RSD
4.0
7.0
21
4.0
41
16
8.0
2.0
3.0
    Cyano-complexes of Pt and Fe were added to the POTW and petroleum
    refinery effluents, respectively; and thiocyanate was added to the metals
    finishing effluent to demonstrate that the FI/LE system does not determine
    these forms of cyanide.

17.0   Glossary of Definitions and Purposes

The definitions and purposes are specific to this method but have been conformed to common
usage as much as possible.

17.1    Units of weights and measures and their abbreviations

        17.1.1 Symbols
              °C     degrees Celsius
              %      percent
              ±       plus or minus
              >       greater than or equal to

        17.1.2 Alphabetical characters
              g       gram
              L       liter
              mg     milligram
              mg/L   milligram per liter
              //g     microgram
 August 1999
21

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 Method OIA-1677
Mg/L
mL
ppm
ppb
M
microgram per liter
milliliter
parts per million
parts per billion
molar solution
17.2    Definitions
        17.2.1  Available cyanide consists of cyanide ion (CN~), hydrogen cyanide in water
               (HCNaq) and the cyano-complexes of zinc, copper, cadmium, mercury, nickel, and
               silver.

        17.2.2  Calibration blank—A 100 mL volume of reagent water treated with the ligand-
               exchange reagents and analyzed using the FIA procedure.

        17.2.3  Calibration standard (CAL)—A solution prepared from the dilution of stock
               standard solutions.  A 100 mL aliquot of each of the CALs are subjected to the
               analysis procedure. The resulting observations are used to calibrate the instrument
               response with respect to the analyte concentration.

        17.2.4  Discharge—Specific discharge (also known as  "matrix type") means a sample
               medium with common characteristics across a given industrial category or
               industrial subcategory. Examples include:  C-stage effluents from chlorine bleach
               mills in the Pulp, Paper, and Paperboard industrial category; effluent from the
               continuous casting subcategory of the Iron and Steel industrial category; publicly
               owned treatment work (POTW) sludge; and in-process streams in the Atlantic and
               Gulf Coast Hand-shucked Oyster Processing subcategory.

               Specific discharge also means  a discharge with characteristics different from other
               discharges. Therefore, if there are multiple discharges from a facility all with the
               same characteristics, these are the same discharge for the purpose of
               demonstrating equivalency of a method modification. In this context,
               "characteristics" means that results of the matrix spike and matrix spike duplicate
               (MS/MSD) tests with the unmodified method meet the QC acceptance criteria for
               recovery and relative percent difference (RPD).

        17.2.5  Initial precision and recovery (TPR)—Four aliquots of the LRB  spiked with the
               analytes of interest and used to establish the ability to generate acceptable
               precision and accuracy. An IPR is performed the first time this method is used and
               any time the method or instrumentation is modified.

        17.2.6  Laboratory control sample (LCS)—An aliquot of LRB to which a quantity of
               mercury (II) cyanide stock solution is added in the laboratory. The LCS is
               analyzed like a sample. Its purpose is to determine whether the methodology is in
               control and whether the laboratory is capable of making accurate and precise
               measurements.
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                                                                           Method OIA-1677
       17.2.7 Laboratory reagent blank (LRB)—An aliquot of reagent water that is treated like a
              sample including exposure to all glassware, equipment, and reagents that are used
              with other samples.  The LRB is used to determine if the method analyte or other
              interferences are present in the laboratory environment, reagents, or apparatus.

       17.2.8 Matrix spike/matrix spike duplicate (MS/MSD)—An aliquot of an environmental
              sample to which a quantity of the method analyte is added in the laboratory.
              MS/MSDs are analyzed like a sample.  Their purpose is to determine whether the
              sample matrix contributes bias to the analytical results. The background
              concentration of the analyte in the sample matrix must be determined in a separate
              aliquot and the measured values in the MS/MSD corrected for the background
              concentration.

       17.2.9 Minimum level (ML)—The level at which the entire analytical system shall give a
              recognizable signal and acceptable calibration point, taking into account method
              specific sample and injection volumes.

       17.2.10  Ongoing precision and recovery (OPR)—See Laboratory control sample
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