Electrokinetic Preseparation and Molecularly Imprinted Trapping for Highly Selective SERS Detection of Charged Phthalate Plasticizers

Abstract

Nonspecific binding and weak spectral discernment are the main challenges for surface-enhanced Raman scattering (SERS) detection, especially in real sample analysis. Herein, molecularly imprinted polymer (MIP)-based core−shell AuNP@ polydopamine (AuNP@PDA-MIP) nanoparticles (NPs) are designed and immobilized on an electrochemically reduced MoS 2 -modified screen-printed electrode (SPE). This portable electrochemical−Raman interface offers the dual functions of electrokinetic preseparation (EP) and MIP trapping of charged molecules so that a reliable SERS recognition with molecular selectivity and high sensitivity can be achieved. Core−shell AuNP@PDA-MIP NPs can be controllably synthesized, possess predesigned specific recognition, and provide "hot spots" at the junction of NPs. The introduction of an electric field enables the autonomous exclusion and separation of similarly charged molecules as well as attraction and concentration of the oppositely charged molecules by electrostatic attraction. Subsequently, the specific MIP recognition cavities allow selective adsorption of targets on the interface without the interference of analogues. Owing to the distinctive design of the multiple coupling separation, trapping, and enrichment strategies, the MIP-based SERS-active interface can be used for label-free detection of charged molecules in real samples without pretreatment. As a proof-of-concept study, label-free SERS detection of charged phthalate plasticizers (PAEs) was demonstrated with a detection limit as low as 2.7 × 10 −12 M for dimethyl phthalate (DMP) and 2.3 × 10 −11 M for di(2-ethylhexyl) phthalate (DEHP). This sensing strategy for in situ SERS analysis of charged pollutants or toxins holds vast promises for a wide range of in-field applications.

Latest Advances and Developments to Detection of Micro‐ and Nanoplastics Using Surface‐Enhanced Raman Spectroscopy

“…Moreover, label‐free SERS detection of charged PAEs was demonstrated by Yang et al. [ 123 ] with a detection limit as low as 10 −12 m for DMP and 10 −11 m for di(2‐ethylhexyl) phthalate (DEHP). As a proof‐of‐concept study, this sensing strategy for in situ SERS analysis of charged pollutants or toxins holds vast promises for a wide range of in‐field applications.…”

“…Yang et al. [ 123 ] developed a method for electrokinetic preseparation and molecularly imprinted trapping that allowed the identification of toxic PAEs by using SERS. Their proposal consisted of core–shell nanostructures with single Au NPs encapsulated in a molecularly imprinted polymer (MIP)‐based polydopamine (AuNP@PDA‐MIP).…”

Nanotechnology in food and water security: on-site detection of agricultural pollutants through surface-enhanced Raman spectroscopy

“…Yang et al [ 9 ] used SERS for the identification of phthalate plasticizers. Instead of using nanoparticles directly for the detection, they designed an electrochemically reduced MoS 2 -modified electrode decorated with molecularly imprinted polymer-based core–shell AuNP polydopamine nanoparticles.…”

“…SERS is a good alternative for on-site detection systems, which can be integrated with developed SERS probes and portable Raman spectrometers. For the on-site detection, many different detection platforms or SERS probes were fabricated, such as microfluidic devices, paper-based, and swab-based systems [6][7][8][9]. With such systems, sample volume can be decreased, sample handling can be automatized, and the whole system can be turned into a portable device.…”

Surface-Enhanced Raman Spectroscopy Detection of Cerebrospinal Fluid Glucose Based on the Optofluidic In-Fiber-Integrated Composites of Graphene Oxide, Silver Nanoparticles, and 4-Mercaptophenylboronic Acid

“…It is widely used in biochemistry, clinical medicine, and other tests. 4,5 Silver nanoparticles (Ag NPs) as traditional SERS enhanced substrates are widely used in Raman detection. 6 In recent years, in Raman detection research, the purpose of mixing Ag NPs with other materials for preparing a composite SERS substrate with special properties is to achieve better detection results for the detected objects.…”