A fast and simple method to perform cyanide detection using ATP stabilized gold nanoparticles combined with the Cu(DDTC)2 complex

Abstract

A method has been developed for the determination of cyanide using gold nanoparticles stabilized with adenosine triphosphate (ATP), and in the presence of the Cu(DDTC)₂ complex. Cyanide reacts with copper, and free diethyldithiocarbamate (DDTC) causes nanoparticle aggregation. The reaction was performed in a buffered medium (10 mM phosphate + 0.1 M NaCl) by mixing stabilized gold nanoparticles (1.27 × 10⁻⁹ M; 19.2 ± 4.0 nm), the Cu(DDTC)₂ complex and cyanide solutions. The influences of the measurement time after the addition of cyanide, the pH of the reaction medium and the concentration of the complex were evaluated. The selected conditions were: time = 1 min, [Cu(DDTC)₂] = 0.1 μM and pH = 10.4. The analytical performance of the assay was studied, with a LOD of 0.059 mg L⁻¹ which is under the level proposed by the USEPA for drinking water (0.2 mg L⁻¹).