A Study on Ninhydrin Reaction with Weak Acid Dissociable Cyanide and Its Application for Toxic Cyanide Determination
Andriana Risk Surleva,
Sabina Bancila,
Elena Veselinova Todorova
Issue:
Volume 2, Issue 1, January 2014
Pages:
1-6
Received:
25 November 2013
Published:
20 December 2013
Abstract: Environmental Protection Agencies impose stringent limits for weak-acid dissociable metal-cyanide complexes (WAD) content in waters. The maximum contaminant level in drinking water is as low as 50 µg/L as CN-. Hence, sensitive methods for WAD cyanide determination are strongly required. Recently, ninhydrin reaction with free cyanide has been proven as a very sensitive at 485 nm (ε = 1.2 105 L/mol.cm), fast (15 min), selective and with non-toxic reagents. In the presence of free cyanide the absorbance measurement was based on the formation of a red hydrindatin resulting from cyanide’s catalytic effect on ninhydrin at pH 10.8. This report presents the results from a study on the reaction between ninhydrin and complexed cyanide at ambient conditions. The WAD complexes: Hg(CN)42-; Ni(CN)42-; Cu(CN)43-; Ag(CN)2-; Zn(CN)42-; Cd(CN)42- are discussed. The reaction kinetic and standard curves are presented. Ligand exchange approach was applied without additional separation. Ninhydrin was showed to be selective and sensitive for direct cyanide quantification.
Abstract: Environmental Protection Agencies impose stringent limits for weak-acid dissociable metal-cyanide complexes (WAD) content in waters. The maximum contaminant level in drinking water is as low as 50 µg/L as CN-. Hence, sensitive methods for WAD cyanide determination are strongly required. Recently, ninhydrin reaction with free cyanide has been proven...
Show More
