Cyanide is a very strong poison and is the salt or ester of hydrocyanic acid. Cyanide has organic and inorganic varieties or is produced and used by various chemical processes. Organic compounds of cyanide are collected under the nitrile group and are generally not toxic. It is used in the production of a number of drugs.

Cyanide is also produced by some animals and plants. Numerous plants, bacteria and insects produce cyanide naturally. Apricot, cherry, almond, plum, peach, potato, bean, cabbage, radish, corn and broccoli plants also produce cyanide compounds.

When cyanide is referred to, in fact all cyanide compounds are meant. Cyanide compounds are divided into two groups as simple and complex cyanides. Most simple metal cyanides are insoluble or slightly soluble. Cyanide, which is in the form of free or metal complex, is used in industrial plants, metal polishing, electrolytic coating, petroleum, chemical, steel and mining enterprises and is thus spread to the environment.

Low concentration of cyanide is very important because cyanide is also toxic in wastewater and has wide usage in industry. Since it has a strong poisoning effect, the highest levels of cyanide in fresh water and sea water have been determined by 5 micrograms per liter for environmental protection purposes. It is very important to determine the amount of cyanide in water in order to protect environmental health and ensure that natural life is not damaged.

Numerous methods have been developed by electro analytical, fluorometric, chromatographic, atomic absorption spectrophotometer and spectrophotometric methods to determine total concentrations of low concentrations of cyanide in water.

Laboratories accredited by national and international accreditation bodies carry out the determination of total cyanide within the framework of water and wastewater measurements. These laboratories operate in compliance with the TS EN ISO / IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories.