In the Federal Register of April 6, 2004, there is a proposed new set of cyanide determination methods. We have added to the InfoMine library a twelve page set of comments on the proposed determination methods, as sent to us by Dr. Charles Bucknam, who for many years has run the LabMine site. Here is the introduction to give you the scope of the problem:

Distillation-based methods for determination of operationally defined cyanide have very limited application because of the serious interferences from the species likely to be found in most of the cyanide containing effluents. To the best of our knowledge, there are no reliable spot tests for detecting the presence of some of these interfering species. Hence, distillation-based methods should only be used for cyanide determination of samples that have well defined and constant matrix that do not contain interfering species. For example, distillation-based methods should not be used for cyanide determination of samples originating from precious metals cyanidation effluents, water treatment plants, petroleum refineries, coke producing plants, elemental phosphorous producing facilities, etc. In addition, these methods should not be used to monitor cyanide detoxification processes because cyanide and oxidant(s) (sulfite, thiosulfate, peroxide, etc.) can coexist in solution. The high temperature during distillation shifts the equilibrium towards the formation of the oxidation products (OCN- and/or SCN-, etc.), which can result in serious underestimation of cyanide levels that are actually present in the original sample.