Magnetic ordered mesoporous carbon composites incorporating Ag nanoparticles as SERS substrate for enrichment and detection of trace mercaptan compounds

MIPs-SERS Sensor Based on Ag NPs Film for Selective Detection of Enrofloxacin in Food

The quinolone antibiotics represented by enrofloxacin (ENRO) are harmful to the ecological environment and human health due to illegal excessive use, resulting in increasing food residues and ENRO levels in the environment. To this end, we developed a MIPs-SERS method using surface-enhanced Raman spectroscopy (SERS) and molecularly imprinted polymers (MIPs) to detect ENRO in food matrices. Firstly, a layer of silver nanoparticles (Ag NPs) with the best SERS effect was synthesized on the surface of copper rods as the enhancing material by in situ reductions, and then MIPs targeting ENRO were prepared by the native polymerization reaction, and the MIPs containing template molecules wrapped on the surface of silver nanoparticle films (Ag NPs-MIPs) were obtained. Our results showed that the Ag NPs-MIPs could specifically identify ENRO from the complex environment. The minimum detection limit for ENRO was 0.25 ng/mL, and the characteristic peak intensity of ENRO was linearly correlated to the concentration with a linear range of 0.001~0.1 μg/mL. The experimental results showed that in comparison to other detection methods, the rapid detection of ENRO in food matrices using Ag NPs-MIPs as the substrate is reliable and offers a cost-effective, time-saving, highly selective, and sensitive method for detecting ENRO residues in real food samples.

Soft-template solvent thermal method synthesis of magnetic mesoporous carbon-silica composite for adsorption of methyl orange from aqueous solution

A facile soft-template solvent thermal strategy was developed to prepare mesoporous carbon-silica composite (MMCS) by using furfuryl alcohol (FA) as carbon precursor, Pluronic copolymer P123 as template, hydrated iron nitrate as iron source, and teraethylorthosilicate as silicon source and it was applied for the removal of methyl orange (MO). The as-synthesized MMCS with abound of hydrophilic groups processed a high specific surface area, large pore volume, and good magnetic response. With the increased amount of FA, the surface area and functional groups increased, promoting the adsorption effect. The maximum adsorption capacity of MO on MMCS can be high to 113.1 mg g^-1 at pH 4 with 150 mg L^-1 initial MO concentration. The adsorption isotherm, kinetic, and thermodynamics were all studied and the results showed the adsorption process well fitted Langmuir adsorption isotherm and pseudo-second-order model. Additionally, it was shown that the adsorption process could not be interfered by the co-existence of PO₄^3-, NO₃^-, CO₃^2-, SO₄^2-, and real water matrix. And the proposed adsorbent can remove MO in three practical water samples with satisfied removal rates ranging from 92.8 to 99.8%. Thus, the MMCS prepared in this study could be utilized as an alternative adsorbent for the removal of methyl orange from practical aqueous solution.