Quantification of adsorbed and dangling citrate ions on gold nanoparticle surface using thermogravimetric analysis

Abstract

A novel approach involving thermo-gravimetricanalysis (TGA) for the quantification of citrate ions present on the surface of gold nanoparticles has been reported. TGA study was carried out on AuNPs in response to parameters such as concentration of tri-sodium citrate and pH of gold nanoparticles depicting that the number of citrate ion present on gold nanoparticles is highly pH dependent. In general, the citrate ions were observed to be higher in alkaline conditions contradicting earlier beliefs. These results also underline the significance of TGA as a novel tool for quantification of citrate molecules present on gold nanoparticle surface. Thus, the present approach not only provides with an insight into mechanistic details of gold nanoparticle synthesis but also opens the usage of TGA for understanding the nano range association of molecules.

[Retracted] Solanum tuberosum Leaf Extract Templated Synthesis of Co3O4 Nanoparticles for Electrochemical Sensor and Antibacterial Applications

“…In particular, citrate ion is widely used in the pharmaceutical industry as an anticoagulant agent to stop accidental blood clotting and in the food industry as a preservative across the broad spectrum of foods and various beverage products. Since, citrate especially in urine is considered to inhibit the crystallization of the content of calcium salt leading to nephrolithiasis and hypocitraturia [ 5 ].…”

A Greener Chemistry Process Using Microwaves in Continuous Flow to Synthesize Metallic Bismuth Nanoparticles

“…This calculation made it possible to obtain a value of a number of citrate molecules per nanoparticle ( n ligand ) and then a surface density of ligand equal to 1 citrate per nm 2 for bismuth NPs obtained by batch and by the flow process. This surface density is directly dependent on the metal studied, nanoparticle size, pH of the colloidal solution, and chemical composition of the nanoparticle surface, as described in the literature …”

Analyzing the surface of functional nanomaterials—how to quantify the total and derivatizable number of functional groups and ligands

“…Moreover, TGA has been used in multi-method approaches for quantitative analysis to enhance the reliability of the results by comparing them with information from FTIR, NMR, ICP-MS/OES, and XPS measurements [164,175,186,[253][254][255][256]. And just recently, TGA has been applied to quantify adsorbed citrate molecules on the surface of gold NP, which provided new insights into mechanistic details of the well-known Turkevich gold NP synthesis method [257].…”

“…ATR-FTIR, DRIFTS, and SERS All FG with IR/Raman-active transition bands Label-free or reporter-based b Any physical state, free of contaminants Calibration or chemometric tools required [ 189 – 212 ] XPS/XRF Incl. HAXPES and TXRF/GIXRF All elements except H, He, Li Label-free or reporter-based b Sample deposited on planar substrate Calibration required [ 23 , 28 , 157 , 158 , 213 – 240 ] TGA/DSC Thermal analysis (mass change or heat quantity) In principle all organic FG/ligands Total FG Label-free Powder, dispersion, film (TGA), or gel (DSC); free of contaminants Calibration-free [ 164 , 175 , 186 , 246 – 257 ] EA Quantitatively analysis of combustion products C/H/N/S-containing FG, O and F also possible Any physical state Calibration required [ 126 , 241 – 245 ] a Depending on the size of the adsorptive reporter: small metal ion reporters will yield the total number of FG (or a value very close to this number), while larger dye reporters will yield a lower number of derivatizable FG b Depending on the chemical nature of the NM and the FG of interest, either intrinsically present moieties (label-free) or specific reporters (label-based methods) can be utilized for signal generation and quantification, yielding either the total or the derivatizable number of FG …”