Gold-Citric Acid Colloidal Solution (Au, Purity: 99.9 %, Diameter: 100nm)

Typical Properties
CAS	7440-57-5
Catalog	ACM7440575-170
Molecular Weight	196.97 g/mol
Boiling Point	2808 °C (lit.)
Melting Point	1063 °C (lit.)
Flash Point	4 °C
Purity	99.9 %
Density	19.3 g/mL at 25 °C (lit.)
Appearance	Colloidal Suspension
Storage	2-8 °C
Color	Light orange-Dark red
Composition	Au
Concentration	2-3 wt.% (Available as per Customer requirement)
Diameter	100 nm
pH	3
Precautions for use	According to different application fields, mix with other material systems according to the recommended dosage, and use it after fully stirring. ·For industrial catalysts, recommended dosage: ≥20ppm; ·For beauty and health care products, recommended dosage: ≥3ppm.
Quality Level	200
Shipping	Ambient Temperature
Solvent	Water

Overview

Description

Gold nanoparticles dispersion is to disperse gold nanoparticles into a solvent to form a neutral solution with stable and uniform color. The color of the solution is not golden yellow but red. If other substances are added to form a condensed state, the solution turns blue. The solution has the same antibacterial properties as nano silver, and also has better safety for human consumption and contact. Gold nanoparticles have been widely used due to their unique physical and optical properties.

Features

·Evenly dispersed, small particles
·Good compatibility, easy to disperse, easy to add a variety of systems
·Good system stability, reliable performance, safety and environmental protection
·High specific surface area, high loading, easy surface functionalization

Application

·Electronics: Gold nanoparticles are used as conductors in everything from printing inks to electronic chips.
·Photodynamic therapy: Gold nanoparticles (including nanoshells and nanorods) in the near-infrared absorption band generate heat when excited by light at wavelengths of 700 to 800 nm. This feature enables the nanoparticles to destroy targeted tumors.
·Therapeutic agent delivery: Therapeutic agents can be coated on the surface of gold nanoparticles.
·Sensors: Gold nanoparticles are used in various sensors.
·Diagnosis: Detection of Biomarkers
·Probes, catalysis, fuel cells

Case Study

Photoreduction Synthesis Strategy of Monodisperse Gold Nanoparticles

Yasuhiro Shiraishi, et al. RSC Advances, 2017, 7, 6187-6192.

Generally speaking, a colloidal suspension of gold nanoparticles (AuNPs) in water can be prepared through thermal reduction using HAuCl4 as raw material and citric acid as reducing agent and surface stabilizer. In order to avoid the aggregation of AuNPs, a method was developed to prepare monodisperse AuNPs by reducing HAuCl4 under UV irradiation. The size of AuNPs can be adjusted by changing the intensity of UV light or the amount of citric acid added.
· Preparation of AuNPs by photoreduction
Water (2 mL) containing HAuCl4·4H2O (0.2 mM) and citric acid (0.5 mM) was stirred at 25 °C under irradiation of 254 nm light by a Xe lamp (light intensity: 150 mW m-2). LSPR absorption of AuNPs appears at 530 nm and increases with irradiation time. In this case, red-shifted absorption scarcely appears, indicating that the formed AuNPs scarcely aggregate.
· Mechanism for AuNPs Formation
AuNPs are formed by UV irradiation of the citrate-AuCl complex, along with a formation of LSPR absorption. Consecutive photoexcitation of the citrate-AuCl complexes reduces Au to Au with the oxidation of citric acid. Increased light intensity creates smaller AuNPs and monodispersed 50-70 nm AuNPs can be produced.