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Cyanide (free) Test Kits

Cyanide (free) Test Kits

What is Cyanide?
Cyanide (CN) is a carbon nitrogen compound used in many chemical and refining processes. It readily reacts with transition metals which makes it useful for industrial purposes but also makes it a toxic compound. Cyanide is often found in effluent from electroplating and metal cleaning operations, coke ovens, steel manufacturing facilities, gas scrubbers, and polymer production. Free cyanide is defined as the sum of molecular hydrogen cyanide (HCN) and cyanide ion (CN). Total cyanide is the sum of all inorganic forms of cyanide that dissociate into free cyanide when refluxed under strongly acidic conditions.

Why Test for Cyanide?
Cyanide can be safely removed from water by alkaline chlorination. However, due to its acute toxicity to aquatic life, discharges from industrial and municipal wastewater facilities are regulated through permitting processes, necessitating routine effluent monitoring. Due to the potential for both short-term and long-term health effects to humans, the Maximum Contaminant Level for free cyanide in drinking water is 0.2 mg/L. It is common to monitor effluents and surface water supplies for cyanide to ensure that it is not entering natural waters or potential drinking water sources.

About Our Test Kits
CHEMetrics’ free cyanide water test kits are applicable for monitoring effluents and surface water supplies. Sample pretreatment to remove hydrogen sulfide is recommended. For total cyanide analysis, distillation of the sample is required.

CHEMetrics offers both visual and instrumental test kits employing the Isonicotinic-Barbituric Acid Method for the measurement of free cyanide in water.

The CHEMets® visual colorimetric test kit develops a blue-purple color in direct proportion to the free cyanide concentration. Measurements are made against a color comparator. Results are expressed as ppm (mg/L) cyanide.

Vacu-vials® instrumental cyanide testing requires the use of a CHEMetrics direct-readout photometer or spectrophotometer capable of accepting a 13-mm diameter round cell.

Click on a catalog number in the tables below for more information or to purchase a test kit.

Visual Kits

Range MDL Method Kit Catalog No. Refill Catalog No.
0-0.1 & 0.1-1 ppm 0.005 ppm Isonicotinic-Barbituric Acid K-3810 R-3810

Instrumental Kits

Range Method Kit Catalog No.
0-0.400 ppm Isonicotinic-Barbituric Acid K-3803

The Isonicotinic-Barbituric Acid Method

Reference: S. Nagashima, Spectrophotometric Determination of Cyanide with Isonicotinic Acid and Barbituric Acid, International Journal of Environ. Anal. Chem., 1981, Vol. 10, pp. 99-106.In the Cyanide CHEMets® and Vacu-vials® Kit, chlorine is added to a sample that has been buffered to pH 6. The resulting cyanogen chloride reacts with isonicotinic and barbituric acids to form a blue color. Results are expressed as ppm (mg/L) CN. 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 noxious and hazardous fumes from the pyridine reagent.