Direct Detection of β-Agonists by Use of Gold Nanoparticle-Based Colorimetric Assays

Abstract

β-Agonists fed to animals for human consumption pose a serious threat to human health. Fast, broad-spectrum detection methods are needed for on-site screening of various types of β-agonists from animal feeds, meats, and animal body fluids. We developed a colorimetric assay that uses gold nanoparticle (AuNP) plasmon absorption to realize quick detection of β-agonists from liquid samples. β-Agonists showed the capability of directly reducing HAuCl(4) into atomic gold, which involved oxidation of the amine or phenol group on the benzene ring of the β-agonists. The resulting atomic gold formed AuNPs spontaneously, which had strong plasmon absorption at 528 nm. The linear relationship between the concentrations of β-agonists and the AuNPs plasmon absorbance granted quantitative determination of β-agonists in solution. The AuNPs colorimetric assay showed different sensitivities toward β-agonists with different substituent groups on the aromatic ring. β-Agonists with phenol groups had a lower limit of quantitation (LOQ) than those with amine groups. High-resolution transmission electron microscopy (TEM) images revealed the sizes of the AuNPs were in the range 15-25 nm, while X-ray energy-dispersive spectroscopic data suggested the smaller particles observed in TEM with lower contrast may be salt particles from the buffer solution. The developed colorimetric assay can potentially be used for the detection of β-agonists and their analogues from serum, urine, and other liquid samples in the presence of interference from common antibiotics and glucose.

Broad screening and identification of β-agonists in feed and animal body fluid and tissues using ultra-high performance liquid chromatography-quadrupole-orbitrap high resolution mass spectrometry combined with spectra library search

“…Previously, our group developed a broad spectrum screening method for b-agonists using gold nanoparticle-based colorimetric assay (He, Shen, Liu, Luo, & Li, 2011). Unfortunately, the colorimetric assay has an unsatisfactory selectivity, as compounds possessing phenol or amine groups may undergo a redox reaction with HAuCl 4 resulting in false positives.…”

Room temperature seed mediated growth of gold nanoparticles: mechanistic investigations and life cycle assesment

“…[16][17][18][19][20][21] The physical properties of AuNPs (e.g., color, localized surface plasmon resonance (LSPR), electrical conductivity, etc.) 13,[23][24][25][26][27] Such methods are promising in that they entail very simple sample handling procedures, minimum instrumental investment, and can be carried out in the field using portable devices. 22 For example, aggregation induced changes in plasmon response can be coupled with colorimetric detection mechanisms to establish rapid analyte detection.…”

Conductometric sensor for ammonia and ethanol using gold nanoparticle-doped mesoporous TiO2

“…The formation mechanism for the Au NP deposition on the TiO 2 beads can be explained as follows: First, under mild basic pH conditions, HAuCl 4 is easily hydrolyzed and produces a monolayer of Au(OH) 3ad [19]. Secondly, the amino group of the template agent in the TiO 2 precursor beads that can form protons by interacting with HAuCl 4 undergoes an oxidation reaction [10,20], at the same time as Ti(OH) x is hydrolyzed and hydronium ions are produced. Finally, the Au(OH) 3ad is reduced to Au NPs under consumption of protons:…”