Method for the colorimetric determination of the cyanide concentration of aqueous solutions
US4871681A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 1987 |
| Grant date | Oct 3, 1989 |
| Priority date | — |
| Expiry date | Nov 30, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/172307
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
According to the invention, cyanide concentrations of approximately 0.001 to 5 mg cyanide/1 are colorimetrically determined in a continuous manner by means of the known cyanidepicric acid color reaction. The solution containing free cyanide and/or cyanide releasable from cyanocomplexes is converted in a system enclosed in a gas-tight manner in the presence of chelate complexing agents, picric acid and alkaline buffer systems in 1-60 minutes at 50.degree.-120.degree. C. to the color complex and the absorbency is measured spectrophotometrically. The method avoids the extraction step which was previously necessary under 0.2 mg CN/1, avoids errors due to HCN gas evolution losses, is easy to manage, not prone to trouble and suitable for the continuous monitoring of waste-water streams or for controlling cyanide detoxification methods.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.