Preparation of SiO2@Ag@molecular imprinted polymers hybrid for sensitive and selective detection of amoxicillin using surface-enhanced Raman scattering

Abstract

In this work, we fabricated a 300 nm-sized silver-coated silica (SiO2@Ag) SERS substrate. Based on SiO2@Ag, we designed SiO2@Ag@molecular imprinted polymers (SiO2@Ag@MIPs) to realize selectively detection of amoxicillin by coating a molecular imprinted layer averagely thinner than 10 nm on SiO2@Ag. The as-prepared SERS-active substrate demonstrates excellent enhancement for amoxicillin as well as the enhancement factors were 1.63 × 106 of SiO2@Ag@MIPs and 2.97 × 105 of SiO2@Ag, respectively. The SiO2@Ag@MIPs core–shell hybrids as SERS substrates and the minimum detectable concentration of amoxicillin was as low as 2.7 × 10-9 M, and the detection limit of SiO2@Ag was 2.7 × 10-7 M. The linear relationship between intensities of characteristic peaks and concentrations of amoxicillin was established. Both SiO2@Ag and SiO2@Ag@MIPs substrates were highly sensitive and could achieve qualitative and semi-quantitative analysis of amoxicillin in aqueous media with good linear correlations. Based on the above, SiO2@Ag@MIPs will be conducive to detecting actual samples and expanding the practical application.