Total cyanide

Cyanide solutions are used almost exclusively. One typical solution contains copper cyanide 26 g/1, zinc cyanide 11 g/1, sodium cyanide (total) 45 g/1 and sodium cyanide ( free ) 7 g/l This bath is operated at pH 10.3-11.0, 110 A/m and 27-35 C, with 75 Cu-25 Zn alloy anodes. Many other solutions are used including a special rubber-bonding bath and a high-speed bath which is capable of being used at up to 16 A/dm . ... 

EPA. 1983a. Methods for chemical analysis of water and wastes. Method 335.2. cyanide, total. Environmental Monitoring and Support Faboratory, EPA, Cincinnati, OH. 

The above procedure is similar to the analysis of total cyanide in the alkaline distillate described in the preceding section, except that the sample pH are different. In the above method, chlorination is done on the alkaline sample at a pH between 11.5 and 12. On the other hand, in the determination of cyanide (total), the pH of the distillate is maintained below 8 with acetate buffer before adding chloramine-T solution. 

Pyridine-Barbituric acid see under Cyanide, Total (Chapter 2.6)... 

Results from Cyanide without iron cyanide Total cyanide ... 

J9etection of Location — Cyanide without Iron Cyanides (Short-term Stable Cyanides) Total Cyanide Total Cyanide... 

Country Chlorine Phosgene Diphosgene Mustard Chloropicrin Cyanides Total... 

Four procedures are available for the determination of cyanide in environmental media. These are free cyanide, total cyanide, weak acid dissociable (WAD) cyanide and amenable to chlorination (ATC) cyanide. Free cyanide is that portion of the cyanide which exists as hydrogen cyanide or as the CN- ion. Total cyanide is the cyanide released from a sample by digestion with strong mineral acid at elevated temperature. The cyanide released is distilled and... 

In the regulatory analysis of water samples, cyanide content is usually expressed in various forms as free cyanide, total cyanide, weak-acid dissociable cyanide, available cyanide, and cyanide amenable to chlorination. In wastewater, cyanide usually exists as CN and HCN, or in the form of a complex ion. Simple cyanides can be subdivided into soluble and insoluble complexes. Cyanide forms complexes with a number of metals, including cobalt, nickel, gold, iron, copper, silver, cadmium, and zinc, which are frequently found, along with cyanide, in industrial wastewater. The cyanide complexes usually have high-thermod5mamic stability constants as indicated by log /3 values in Table 9.1. 

---