Photochemically mediated synthesis of a gold colloid by dithizone and its application in the amperometric sensing of thiocyanate

Abstract

This paper highlights a one-step facile approach for the photochemically assisted synthesis of stable gold colloids (Au) using dithizone (DTZ) without any extra controls, viz. surfactant, seeds, pH etc. Although dithizone chemistry has been documented extensively in scientific reports, it is amazing to note that there are scarcely any reports published so far on the photochemically mediated formation of gold nanostructures using dithizone. The as-prepared electroactive hybrid nanomaterial was extensively investigated using various characterization techniques, including UV-visible spectroscopy, FT-IR, cyclic voltammetry, amperometry, TEM, FESEM and XPS. The formation of the gold nanostructure over time by exposure to light using dithizone was ascertained, with the results complemented by time dependent UV-visible as well as TEM studies. A conceivable reaction mechanism for the formation of the gold nanostructure has also been proposed. The use of dithizone as a reductant as well as a stabilizer offers great advantages in terms of simplicity during synthesis, i.e., a one-pot synthesis, use of aqueous/organic media, no external reducing agent and a very limited post-synthesis work-up. Furthermore, an electroactive advanced hybrid nanomaterial derived from nanoscale gold protected with dithizone (DTZ) and its oxidation product (DTZH) has been utilized for the amperometric sensing of hazardous thiocyanate. The modified electrode with the hybrid material efficiently electrocatalyzes the oxidation of thiocyanate at a potential of 0.55 V vs. AgCl/Ag and shows a linear response toward thiocyanate sensing with a sensitivity of 0.016 mA nM À1 and a limit of detection of 23.348 nM at a S/N (signal-to-noise ratio) of 3. The electrochemistry behind the sensing of thiocyanate is possibly due to electrostatic interactions (DTZH/SCN nÀ /Au m+ /SCN nÀ /DTZH complexation) and the conducting gold nanoparticles facilitating the efficient collection and transfer of electrons to the modified electrode.

Sensitive Amperometric Determination of Thiocyanates at Ionic Liquid Nanohybrid Kaolinite Modified Glassy Carbon Electrode

“…The results obtained were plotted in the graph of Figure 6 where the percentage of the current obtained in the presence of the interfering anion at a given concentration (I%) are represented relatively to the signal without interferences. These percentages were estimated using Equation (4).…”

“…Thiocyanate ions are naturally present in the human body, resulting from foods (milk, cheese and some vegetables) digestion . Since cyanide metabolism also produce SCN − , the concentration of SCN − in biological fluids such as saliva, urine and blood serum is a good indicator of cyanide's intoxication and can be used as fast method to distinguish smokers from non‐smokers . Indeed, cigarettes usually contain high amounts of cyanide.…”

“…Indeed, cigarettes usually contain high amounts of cyanide. In addition, higher concentrations of SCN − in the body result in abnormal proteins dialysis . SCN − can also be found in industrial effluents because of its frequent uses in many industrial processes such as hydrometallurgy, pesticides production, textile dyeing, printing, photography, as well as in the synthesis of some organic compounds .…”

DDAB-Triggered, Size-Sorted, Instant Phase-Switching of Silver Nanoparticles

“…In recent years nanoparticle (NP) synthesis has seen advances leading to higher purity, larger yield, better size dispersion and shape, controlled functionalization, monocrystallinity, etc. just to name a few . NPs can be synthesized through all the known routes of materials synthesis viz.…”

Pd@TTF Tailored Nanostructured Platform: Voltammetric Estimation of Ceftazidime

“…Immense attentions have been drawn by researchers towards the application of noble metal nanostructures (NMN) in various fields such as sensors, nano electronic, optics, biochemical analysis and catalysis . The catalytic efficiency of nanomaterials is significantly affected by their shape and size ,.…”