Available Cyanide by ASTM D 68880 pages

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Available Cyanide by ASTMD 6888

Method Abstract

Scope and Application:

Method Summary:

This method is used for the determination of available cyanide in water and wastewater by

automated ligand exchange, flow injection analysis, and amperometric detection according

to ASTM Method D 6888-09. This method is approved for use in the USEPA's data

gathering and monitoring programs associated with the Clean Water Act.

The Minimum Level (ML) of this method is 2 piglh. The applicable range of this method is

5.0 to 500 piglh cyanide using a 200-^L sample loop. Extend the range to analyze other

concentrations by sample dilution or changing the sample loop volume.

Ligand exchange reagents form thermodynamically stable complexes with the transition

metal ions, releasing the cyanide ion from the cyano-complexes. Addition of acid converts

the cyanide ion to hydrogen cyanide gas (HCN), which passes under a gas diffusion

membrane. The hydrogen cyanide gas diffuses through the membrane into an alkaline

receiving solution where it converts 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 electrode at an applied potential of zero volt. The

current generated is proportional to the cyande concentration present in the original sample.

The quality of the analysis is assured through reproducible calibration and testing of the

Flow Injection Analysis (FIA) system.

Interferences: Method interferences can be caused by contaminants in the reagents, reagent water, and

glassware, which may bias results. Sulfide, at concentrations greater than 50 ppm, is a

positive interferant in this method.

Performance Specifications:

Chemicals: • Acetic acid, glacial, C2H402 (FW 60.05)

• Acetone, C3H60 (FW 58.08)

• Ligand exchange reagent, available cyanide (WAD) reagent A (PN A001416)

• Ligand exchange reagent, available cyanide (WAD) reagent B (PN A001417)

• Bismuth nitrate pentahydrate, Bi(N03)3«5H20 (FW 485.07)

• Deionized water (ASTM Type I or II)

• 5-[4-(Dimethylamino)benzylidene]rhodanine, C12H12N2OS2 (FW 264.37)

• Ethylenediamine, anhydrous, C2H8N2 (FW 60.10)

• Mercury(II) cyanide, Hg(CN)2 (FW 252.63)

• Potassium tetracyanonickelate (II), K2Ni(CN)4) (FW 240.96)

Cartridge # 324405 (800)653-1711

Methodology PN 328938 . _,, _ (979)690-1711

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