Cyanide is used in many chemical and refining processes. It is found in the effluents from electroplating and metal cleaning operations, coke ovens, steel manufacturing facilities and gas scrubbers. Although cyanide can be safely removed by alkaline chlorination, its acute toxicity to aquatic life necessitates routine monitoring of effluents prior to discharge. The Maximum Contaminant Level for free cyanide is 0.2 mg/L in drinking water.

CHEMetrics' cyanide test kits are applicable to the monitoring of effluents and surface water supplies. It is recommended, however, that the sample be distilled and hydrogen sulfide be removed prior to analysis.

The Colorimetric Method. The kit employs the Isonicotinic/Barbituric Acid Method.  To perform a test, two accessory solutions are added to the sample to convert cyanide to cyanogen chloride.  The analyst then snaps off the tip of the reagent ampoule below the surface of the sample.  Sample is automatically aspirated into the ampoule where the resulting cyanogen chloride reacts with the isonicotinic and barbituric acids to form a blue color.  Test results are expressed in parts per million (mg/l) cyanide.  Total testing time is about 20 minutes. This chemistry provides two advantages over the more commonly used pyridine methods: (1) The shelf-life of the reagent is extended, and (2) The analyst is not exposed to the noxious and hazardous fumes from the pyridine reagent.

The Titrimetric Method. CHEMetrics employs silver nitrate as the titrant and dimethylaminobenzalrhodamine as the indicator. A color change from orange to yellow signals the end of the titration. Results are expressed as ppm (mg/L) CN.