Kyle,

Where did you have your CN test done?

A buddy of mine had a YSI photo meter test station and had some cyanide regents that we used, he has since moved away and I am hoping to purchase a similar unit soon as my current colormeter isnt able to perform the tests I would like to... Once I have my unit I will perform tests for a small fee to cover regent costs...

I thought I read that a mass spec was required for that test...

it used a 5 regent test of Pyridine-Barbituric Acid, measuring 0-0.5PPM Cyanide

Kyle, how is this performed on tissue? Is it extracted first? Or?

its a freshwater test that you can run by placing the said fish in a dish of RO water to let any contaminates enter the freshwater column for testing.... I believe thats the way the test was done, it was a few years back that we did it...

I found the 5 reagent method and it uses a spectrophotometer


"quoted in Aubrey Knowles' "Colorimetric Analysis of Metal Finishing & Metal Working Solutions & Effluents" (1999) with sensitivity given in the range of 5-60 and 1-20 ppb, respectively, though I suspect that for the lower end of the range you'll need to use a cell with a long light pathlength (e.g. 10 cm)- check to see if your HACH can accomodate such cells. Essentially, both methods involve oxidation of HCN to cyanogen chloride which is then reacted with methylphenylpyrazolone, bispyrazolone and pyridine in the first case, barbituric acid and pyridine in the second case. Both complexes absorb in the visible (580 and 620 nm resp.) so any working spectrophotometer should do for the higher part of the specified concentration ranges.

Note though that if part of the cyanide is present as metal complexes (which is likely) then a decomposition-distillation-absorption procedure becomes necessary for the separation of cyanide, and it is very tedious. "

I guess the later is why it costs about 3K for a test :rolleyes:

Steve

found another way of testing from a web page, this is a cheeper way but still probably fairly expensive.

"You weigh the fish. You throw the
fish in a blendor (or bass-o-matic.) Then you add concentrated sodium
hydroxide, and reflux (boil with a condensor) the mixture for several
hours. Then, you measure the cyanide concentration with an ion-
selective electrode, and back-calculate the tissue concentration in
the fish."

Steve

that sounds like fun steve, my friend did the test at the time and knew how to use the photometer as he used to run fish farms, I just know what I have stated about the test, the details are a little blurry with me it was a long time ago, what I do know is that he was able to get a positive reading for cyanide

Kyle,

What was your fish farm friend using a test for cyanide for? I've never seen one used here in B.C., just curious.