The MUR of 2012 Clean Water act allows the replacement of Manual Cyanide Distillation for WAD and Available Cyanide. This action makes available at 40 CFR part 136 an additional test procedure for measurement of available cyanide. Currently approved methods for measurement of available cyanide are based on sample chlorination.
Method OIA–1677 uses a flow injection/ligand exchange technique to measure available cyanide. Although Method OIA–1677 and chlorination methods both measure available cyanide, it is possible that the results produced by the two techniques will vary slightly, as detailed in the proposed rule (63 FR 36809, July 7, 1998).
EPA offers Method OIA–1677 as another testing procedure for several purposes, including permit applications and compliance monitoring under the NPDES program under CWA section 402; ambient water quality monitoring; CWA section 401 certifications; development of new effluent limitations guidelines, pretreatment standards, and new source performance standards; and for general laboratory use.
The advantage to this method is the sample is measured directly with saving an immense amount of time due to the elimination of distillation. The sample is picked up from a Cetac autosamplers tray and transported with a ismatec peristaltic pump using peristaltic pump tubes and mixed with acid. This acidified sample passes via Teflon tubing across a gas diffusion membrane module that has an inexpensive and durable membrane. On the other side of the membrane is a stream of NaOH base that receives the cyanide gas and then passes through an amperometric flowcell. The amperometric flowcell has a reference electrode that differentiates between the conductivity of the normal NaOH base stream and when cyanide is present. This produces a fast, accurate and non toxic way to measure cyanide.
To view The Cyanide Clarification of Free and Total Cyanide Analysis for Safe Drinking Water Act (SDWA) Compliance
For more information, please visit: