eur op eanexhibitionofcreati vityandinnovation - Europe Direct Iasi

EUROINVENT 2013
Bulgaria
1.1.
Title
Authors
Institution
Description
Class
ANALYTICAL CONTROL OF CYANIDE IN
ENVIRONMENTAL SAMPLES
Andriana Surleva, Valentin Stojanov
University of Chemical Technology and Metallurgy Sofia
The Environmental Authorities impose stringent demands to
analytical methods for cyanide determination at low levels
considering the high toxicity of cyanide compounds. Besides high
sensitivity, the methods have to be fast, cheap, selective, using nontoxic
reagents at ambient conditions and easily automated and
miniaturized. Considering spectrophotometric analysis as an
available, easy maintained tool for pollutant determination, we
focused our research on color reagents for cyanide determination.
Cyanide compounds are divided in three groups according to their
environmental fate and toxicity: (1) free cyanide – the most toxic,
includes cyanide ion and hydrogen cyanide; (2) weak acid
dissociable cyanide (WAD) – includes free cyanide and metalcyanide
complexes which easy dissociate at environmental
conditions, and (3) total cyanide – all compounds containing CN
group in the molecule.
From environmental point of view, free and WAD cyanides are the
most important and maximum pollutant level is as low as 50 ppb at
drinking and surface water. The ninhydrin was proposed as a
sensitive color reagent for cyanide determination at ppb levels.
Limit of detection was 8 ppb free cyanide and the reaction time was
15 min. The research is now extended on WAD cyanide aiming to
develop an analytical method for low levels WAD cyanide
determination. The preliminary results showed that ninhydrin could
replace cyanide ions in metal-cyanide complex preserving the
sensitivity of obtained color compound. Different reaction rates
were observed according to the lability of metal-cyanide complex
and study on the mechanism of the replacement reaction is initiated.
Due to the fast response of color reaction at ambient conditions, the
non-toxicity of color reagent and the high sensitivity of color
product, a development of a sensitive assay for WAD cyanide
monitoring in environmental samples is currently in progress.
Innovative Research
INTERNATIONAL EXHIBITS
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