Phenothiazine‐Capped Gold Nanoparticles: Photochemically Assisted Synthesis and Application in Electrosensing of Phosphate Ions

Abstract

We describe a green photochemical route for the synthesis of gold nanoparticles (AuNPs) using phenothiazine (PTZH) as a reductant as well as a stabilizer without any extra control (i.e. surfactant, pH, etc.). The synthesized AuNPs are characterized by using UV/Vis spectroscopy, cyclic voltammetry, and transmission electron microscopy. Furthermore, a possible mechanism for the formation of the AuNPs is proposed. This hybrid electrode material, derived from nanoscale gold particles capped with PTZH and its oxidation product, is explored for the development of a highly sensitive amperometric sensor for phosphate ions. The electrochemistry behind the electrocatalytic sensing of phosphate is attributed to the nano‐sized gold particles that are capped with PTZH and its oxidation product, which exhibit high electron‐transfer kinetics through the interaction of the hybrid PTZH–AuNPs with oxygen atoms of ${{\rm{PO}}_4^{3 - } }$. The modified electrode efficiently gives an electrochemical signature of phosphate ions at a potential of −0.336 V versus AgCl/Ag and shows a linear response toward phosphate sensing, with a sensitivity of 0.794 μA μM−1 and a limit of detection of 0.022 μm, at a signal‐to‐noise ratio of 3.

One pot synthesis of coordination polymer 2,5-dimercapto-1,3,4-thiadiazole–gold and its application in voltammetric sensing of resorcinol

“…In this process, the concept of a modied electrode is one of the exciting elds of electroanalytical chemistry. [24][25][26] Several existing electrochemical methods for RS sensing are based on the immobilization of an enzyme on a modied electrode. We have demonstrated a simple non-enzymatic, highly accurate and rapid voltammetric method with a DMDT-Au modied carbon paste electrode for the ultra trace level sensing of RS within a wide range of concentration.…”

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

“…[52][53][54] Chemically modied electrodes generally suffer leaching problems in the supporting electrolyte solution but a remarkable property of Au-DTZH is that it completely adheres to the electrode surface. However, the utility of an enzyme-based modied electrode may be limited by gradual fouling and loss of enzyme activity, and they are also not reusable.…”

“…Such problems may be minimised with the use of hybrid nanomaterial modied electrodes to decrease the overpotential and electrode fouling problems. [52][53][54] Chemically modied electrodes generally suffer leaching problems in the supporting electrolyte solution but a remarkable property of Au-DTZH is that it completely adheres to the electrode surface.…”

Photochemically assisted formation of silver nanoparticles by dithizone, and its application in amperometric sensing of cefotaxime

“…Photochemically assisted formation of metallic nanoparticles is a versatile method for generating metal nanostructures, which includes both academic as well as industrial interests. [1][2][3][4] While reducing the bulk size of metals to nanoparticles and further to few-atom nanoclusters, new properties appear, which are different from bulk and allow fascinating applications in various areas. In the past few decades, noble metal particles have been widely studied for their excellent properties, which are different from bulk, and their potential applications in catalysis, biological labeling, surface-enhanced Raman scattering, microelectronics, optical, and biological and magnetic devices.…”

“…[10][11][12] The reduction routes involved in these studies may be classied in three broadly dened categories, including (i) the use of relatively strong reducing agents, such as sodium borohydride, hydrazine and tetrabutylammonium borohydride to prepare metallic nanomaterials, (ii) the heating of a solution of metallic salt with commonly used reductants such as glucose, sodium citrate, dimethylformamide, ascorbic acid, alcohols or polyols, the oxidation products of which may serve as a particle stabiliser and (iii) the irradiation of the solution containing noble metal ions with ultraviolet or visible light or microwave and ultrasound irradiation without using an external reducing agent. 2,[13][14][15][16][17] In the present work, we adopted a relatively green route for the synthesis of silver nanoparticles using dithizone, which have well-established complexation and photochromic properties with silver as reported in the available literature. [18][19][20] This important feature of dithizone gave clue that silver ions may be photochemically reduced to nanosilver by exposure to light.…”