This standard specifies three methods for the determination of total cyanide (see 2.) in water. This method applies to water containing less than 100 mg/l cyanide. However, higher concentrations can be quantified by diluting the sample appropriately. The methods and corresponding appropriate cyanide content ranges are as follows:
——Spectrophotometric method with pyridine-barbic acid: 0.002 - 0.025 mg - Titration method using Tyndall effect: >0.005 mg Titration method using one indicator: >0.05 mg Many ions and compounds interfere with quantitation; The non-obstructive conditions are shown in Table 1 (this list is not exhaustive). When present alone or in combination, they do not interfere with the separation of hydrogen cyanide up to this limit concentration. The presence of aldehydes, such as formaldehyde, causes low cyanide values due to the formation of cyanohydrins. If any of the limiting concentrations of interfering substances are likely to be exceeded, the sample must be diluted with distilled water before stabilization (see 6.). Other interference occurs with fatty acids. This is distilled and produces soap upon titration with an alkaline solution. Interference also occurs with the presence of elemental sulfur.
JIS K 0400-38-10:1999 history
1999JIS K 0400-38-10:1999 Water quality -- Determination of cyanide -- Part 1: Determination of total cyanide