Zr-MOF-Induced Smart Accumulation Enables Surface-Enhanced Raman Spectroscopic Detection of Dioxin at ppt Level in Food Samples

Chiral spiny L-au@ag@ZIF-8 three-layer core-shell SERS substrate for sensitive detection of quinalphos in tangerines

The sensitive detection of quinalphos in food is crucial due to its improper use and the potential for serious harm. Surface-enhanced Raman spectroscopy (SERS) technology, provides a new way for rapid and ultra-sensitive detection. To exploit the molecular sieving effect of metal-organic frameworks (MOFs) in mitigating interference from food matrix components during pesticide residue detection, a novel chiral spiny L-Au@Ag@ZIF-8 (L-AAZ) three-layer core-shell composite was developed as an effective SERS substrate, with chiral L-AABPs providing abundant "hot spots" and spiny ZIF-8 shell provides excellent absorption properties, causing a five-fold increase in SERS intensity compared to traditional Au@Ag NPs. The experimental results revealed that L-AAZ achieved a high enhancement factor (EF) of 3.15 × 105, a low limit of detection (LOD) of 6.56 × 10-10 M, and a relative standard deviation (RSD) of 14.6 % for malachite green (MG), indicating its superior SERS sensitivity and consistency. Moreover, it demonstrated stable performance, maintaining good storage stability for up to 55 days. The substrate's suitability for the actual fruit sample (tangerine) was confirmed, showing an LOD of 10 ng/mL, demonstrating its capability for rapid and sensitive detection of trace amounts of pesticide residues in food.

Shining a light on environmental science: Recent advances in SERS technology for rapid detection of persistent toxic substances

Persistent toxic substances (PTS) represent a paramount environmental issue in the 21st century. Understanding the concentrations and forms of PTS in the environment is crucial for accurately assessing their environmental health impacts. This article presents a concise overview of the components of PTS, pertinent environmental regulations, and conventional detection methodologies. Additionally, we offer an in-depth review of the principles, development, and practical applications of surface-enhanced Raman scattering (SERS) in environmental monitoring, emphasizing the advancements in detecting trace amounts of PTS in complex environmental matrices. Recent progress in enhancing SERS sensitivity, improving selectivity, and practical implementations are detailed, showcasing innovative materials and methods. Integrating SERS with advanced algorithms are highlighted as pivotal areas for future research.

Recent potential application of metal organic framework as a sensor for the detection of dioxin and dioxin-like organic pollutants

Most organic pollutants pose significant risks to public health and the environment. Of particular concern, toxic chemicals in the environment may lead to a variety of health disorders, including cancer and asthma. There are various classes of organic pollutants, including pesticides, dioxins, volatile organic compounds (VOCs), polychlorinated biphenyls, aromatic hydrocarbons, and polyaromatic hydrocarbons. To ensure the protection of the environment and public health from these toxic organic pollutants, the design of sensing probes is highly relevant for the determination of their limits selectivity and sensitively towards particular analytes. In the area of sensing, metal-organic frameworks (MOFs) have gained tremendous attention for accurate and prompt detection of organic pollutants. Significantly, MOFs, which are porous organic polymers coordinated with metal clusters, can be employed in the sensing of organic pollutants like organochlorine pesticides, organophosphorus pesticides, carbamates, and VOCs. Their unique properties, including tunable porosity, high surface area, complex host-guest chemistry, and extended order, give them the potential to be good sensors for the sensing of a variety of substances like dioxin, dioxin-like compounds, and different organic pollutant. This review discusses a comprehensive view of the recent development of MOFs as good sensors for the sensing of dioxin and dioxin-like organic pollutants.

A core-shell AuNRs@BUT-16 nanocomposite for enhancement SERS detection and efficient removal of deoxynivalenol

INTRODUCTION

Deoxynivalenol (DON) is widely found in grains and poses a serious threat to human health, so there is an urgent need to develop methods for its simultaneous removal and detection. The novel metal organic framework (MOF) material BUT-16 has a high adsorption capacity (79.8%) for DON. Meanwhile, surface-enhanced Raman spectroscopy (SERS) has been widely used for rapid detection of analytes.

OBJECTIVES

The aim of this work is to prepare a material that can be used for enhancement SERS detection and efficient removal of DON.

METHODS

AuNRs@BUT-16 was prepared by in-situ solvothermal method and characterized using a series of characterization tools. AuNRs@BUT-16 was used as an adsorbent and SERS substrate for the removal and detection of DON, and some factors affecting the adsorption and SERS detection were investigated. The adsorption mechanism between DON and AuNRs@BUT-16 was investigated using molecular docking. The proposed SERS method was used to detect DON contamination in real samples.

RESULTS

The prepared core-shell AuNRs@BUT-16 showed a synergistic effect in improving DON adsorption and SERS response. 97.6 % of DON was removed by AuNRs@BUT-16 in aqueous solution, and 70 % in 80 % methanol. The pre-enrichment effect of BUT-16 could trap more DON molecules in the "hot spots" of AuNRs, thus the proposed SERS sensor based on AuNRs@BUT-16 substrate displayed outstanding SERS response and the limit of detection of DON was 3.87 × 10-3 μg/mL. Molecular docking revealed that hydrogen bond and π-alkyl interaction were the main reasons for high affinity between BUT-16 and DON, and Au-O bonds facilitated the adsorption of DON on AuNRs.

CONCLUSIONS

AuNRs@BUT-16 with superior enrichment and SERS detection capabilities has been used for simultaneous removal and SERS detection of DON, and it also has great potential to realize sensitive and selective detection and removal of DON in multiple disciplines.

Probing the effect of protein corona on SERS signals: insights from melamine detection in milk matrix

Matrix effects limit the application of surface-enhanced Raman scattering (SERS) technology in the field of food safety. This study elucidated it from the perspective of protein corona by employing a model system for melamine SERS detection in milk. Compared with the melamine standard solution, higher detection limits (1 mg/L and 10 mg/L) are observed in milk matrix. The melamine signal exhibits an 80% reduction in whey protein solution, suggesting that protein has a significant impact on SERS signals. The changes in particle size, zeta potential and UV-vis spectra indicate the AuNPs interact with whey protein. Forming protein corona inhibits the melamine-induced AuNPs aggregation, reducing the number of 'hot spot' and the adsorption of melamine on AuNPs (from 0.28 mg/L to 0.07 mg/L), which may be responsible for signal loss. The found matrix effect from protein corona provides new insights for developing strategies about reducing matrix effect in SERS application.

Recent advances of MOF-based SERS substrates in quantitative analysis of food contaminants: a review

Advancements in food-contaminant detection technologies can significantly improve food safety and human health. Surface-enhanced Raman spectroscopy (SERS) has become the preferred analytical method for food-safety detection owing to its numerous advantages, which include unique 'molecular fingerprinting' features, high sensitivity, rapid responses, and non-invasive characteristics. Raman-signal enhancements rely heavily on high-performance SERS substrates. In recent years, metal-organic framework (MOF)-based SERS substrates have gained attention as promising candidates for developing SERS technologies owing to their distinctive structures and functions. This review comprehensively examines recent advances in MOF-based SERS substrates, focusing on the main role of MOFs in SERS substrates as well as their typical categories and structures, construction methods, and representative applications in food-contaminant detection. First, the primary roles of MOFs in SERS substrates are briefly introduced. Next, a comprehensive overview of the typical categories and structures of MOF-based SERS substrates is discussed. Subsequently, a fundamental view of the general construction methods for MOF-based SERS substrates is presented. Next, the main applications of MOF-based SERS substrates for food-contaminant detection are summarised. Finally, challenges and perspectives, including improvements in SERS performance and stability, and the unification of SERS mechanisms, are addressed and discussed.

Two-dimensional antimonene as a potential candidate for dioxin capture

Among the serious environmental problems that attracted much attention from the broader public is the high toxicity of dioxins. Considerable efforts have been made to develop techniques and materials that could help in their efficient removal from the environment. Due to its high specific surface area, numerous active sites, and outstanding structural and electronic properties, antimonene is considered for a variety of potential applications in different fields such as energy storage, electrocatalysis, and biomedicine. The present study adds to this portfolio by suggesting antimonene as a promising candidate for dioxin capture. Using density functional theory calculations, we studied the adsorption of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on pristine as well as Ca-, Ti-, and Ni-doped antimonene. Three spatial configurations of the adsorption of TCDD on antimonene were analyzed. The results obtained from the calculation of adsorption energies, charge transfer, and densities of states provide evidence that antimonene outperforms other nanomaterials that have been previously suggested for dioxin capture applications. Therefore, we propose these substrates (i.e., pristine and doped antimonene) as potential capture agents for removing such toxic organic pollutants.

Facet junction engineering for enhanced SERS activity of Ag/Cu2O composite substrates

Featuring ultra-high sensitivity and molecule-specific detection ability, surface-enhanced Raman scattering (SERS) is suitable for the rapid sensing of trace-level chemicals in biological, environmental, and agricultural samples. Although crystal facet junction engineering is a powerful tool to manipulate the optoelectronic properties of semiconducting materials, its correlation with the SERS sensing activity of noble metal/semiconductor composites has still not been clarified. In this work, Ag was deposited on Cu2O nanocrystals enclosed by different facets, including {100} (cube), {111} (octahedron), and {100}/{111} (truncated octahedron), and a detailed study of their SERS performance was carried out. It was found that Ag/truncated-octahedral Cu2O (Ag/Cu2O(J3)) exhibited superior SERS activity to Ag/cubic Cu2O (Ag/Cu2O(C)) and Ag/octahedral Cu2O (Ag/Cu2O(O)). The {100}/{111} facet junction in Cu2O can promote the separation and transfer of photogenerated charge carriers, which is beneficial for enhancing SERS sensing performance. Moreover, Ag/Cu2O(J3) has a higher content of oxygen vacancies, providing extra interfacial charge-transfer pathways to the analyte, which also contribute to improving the SERS activity. The low detection limit of Ag/Cu2O(J3) was 1 × 10-11 M for 4-nitrobenzenethiol, two orders of magnitude lower than that of Ag/Cu2O(C) and Ag/Cu2O(O). In addition, Ag/Cu2O(J3) could detect CV and R6G at concentrations down to 1 × 10-10 M and 1 × 10-8 M, respectively. The findings of this work can provide insightful information for designing metal/semiconductor substrates toward SERS sensing application by regulating the crystal facet junction.