Photochemical decoration of gold nanoparticles on polymer stabilized magnetic microspheres for determination of adenine by surface-enhanced Raman spectroscopy

Journal article

Authors/Editors

Alula, Melisew

Research Areas

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Publication Details

Author list: Alula MT, Yang J

Publisher: Springer

Place: WIEN

Publication year: 2015

Journal: Microchimica Acta (0026-3672)

Journal acronym: MICROCHIM ACTA

Volume number: 182

Issue number: 5-6

Start page: 1017

End page: 1024

Number of pages: 8

ISSN: 0026-3672

eISSN: 1436-5073

Languages: English-Great Britain (EN-GB)

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Abstract

Magnetic microspheres decorated with gold nanoparticles (AuNPs) were prepared and used for the determination of adenine by surface-enhanced Raman scattering (SERS). Magnetic particles were first synthesized by coprecipitation of solutions containing iron(II) and iron(III) ions with ammonium hydroxide. Subsequently, the magnetic particles were suspended into a solution of poly(divinylbenzene-co-methyl methacrylate) to yield polymer-stabilized magnetic microspheres. These were further decorated with AuNPs via a new photochemical reduction method. The magnetic microspheres were characterized by XRD patterns and SEM images. They are shown to represent highly SERS-active substrates by giving an enhancement by almost 7 orders of magnitude compared to conventional Raman spectroscopy. Several factors that affect the photochemical reduction to form the AuNPs were examined. It is found that the concentration of gold ion, UV irradiation time, and citrate concentration have more impact on the reaction rate than on the morphologies of the AuNPs. The gold-decorated magnetic microspheres are highly stable in aqueous solution and capable of concentrating nucleobases. A linear response of the SERS signal to adenine in concentrations up to 10 mu M is found, with a linear regression coefficient of 0.997. The detection limit is estimated to a few hundreds of nM (at an SNR of 3). Based on its specific Raman peak at 734 cm(-1), adenine can be selectively determined without interference by other nucleobases, and a recovery higher than 95 % could be obtained.

Keywords

Gold nanoparticles, Magnetic microspheres, Photoreduction, Surface-enhanced Raman scattering

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