Cyanoline Blue is a mixture of monopyrazolone and bispyrazolone. It is used as a colorimetric reagent for CN- detection. The detection range of CN- by this method is 5 ppb to 10 ppm. The maximum wavelength is 620 nm. A ready-to-use solution can be prepared by dissolving 0.27 g Cyanoline Blue in 20 ml pyridine, followed by dilution with 100 ml of water. The solution is stable for one week at 4 oC. Cyanoline Blue is also used to detect SCN-, OCN-, NH3, and vitamin B12.
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