Available Cyanide by ASTM D 68880 pages
OiAnalytical SS
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:
Range: | 5.0-500 ug/L |
Throughput: | 30 samples/hr |
Precision: | |
5 ppb | <5% |
50ppb | <2% |
500 ppb | <2% |
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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