Headline - EPA Clarifies Rules...

EPA Clarifies Rules on Available and Free Cyanide - Specialty Analytical has the Answer
Specialty Analytical is one of only a handful of laboratories in the United States that offers this capability. Contact the lab for more information or for a quote at 503-607-1331 or info@specialtyanalytical.com.
The following excerpt was taken from the most recent CWA Method Update Rule - Proposed Changes (http://water.eps.gov/scitech/swguidance/methods/upload/methodsprepub.pdf), Page 28 of 167.
5. Because there were no EPA-approved methods for free cyanide when water quality criteria were established for free cyanide EPA recommended measurement of cyanide after a "total" distillation. Analytical methods for free cyanide have been developed, and in today's rule EPA is proposing to add free cyanide as a parameter (24A in Table IB.) For determinations of this parameter, EPA is proposing to allow use of the approved available cyanide method, OIA 1677-09.
Specialty Analytical has purchased equipment and developed Available Cyanide Method OIA-1677 at its laboratory in Clackamas,Oregon. Method OIA-1677 is divided into two parts: 1) sample pretreatment and 2) cyanide quantification via amperometric detection. In the sample pretreatment step, ligand-exchange reagents are added to a sample. Reagents displace cyanide ions (CN-) from weak and intermediate strength metallo-cyanide complexes. In the flow-injection analysis system, a 200-uL aliquot of the pretreated sample is injected into the flow injection manifold. Hydrochloric acid converts the cyanide ions to hydrogen cyanide (HCN), which diffuses through a membrane into an alkaline solution where it is converted back to cyanide ion (CN-). The amount of cyanide ion in the alkaline solution is measured amperometrically with a silver-working electrode, silver/silver chloride reference electrode, and platinum counter electrode at an applied potential of zero volts. Current generated in the cell is proportional to the concentration of cyanide in the original sample, as determined by calibration.
If your permit has a Free Cyanide requirement then you can now use OI-1677 to satisfy this requirement.