Herein, a reusable and portable surface-enhanced Raman spectroscopy (SERS) sandpaper was successfully synthesized for the sensitive detection of S-fenvalerate in foods. Commercial sandpapers were decorated with Ag@SiO₂@Au nanoarrays via a liquid-liquid interface self-assembly method. The capacity of sandpaper to float directly on the cyclohexane-water interface allows nanoarrays to be formed directly on it, thereby minimizing stacking issues typically associated with nanoarray assemblies and significantly enhancing the sensitivity of S-fenvalerate detection. Moreover, the SERS sandpaper was reusable and portable due to its strong adhesion of the nanoarrays. Under optimized testing conditions, the developed SERS sandpaper method was capable of detecting S-fenvalerate, demonstrating a strong linear response within a concentration range of 10^–7–10³ μmol/L, with a limit of detection of 1.92 × 10⁻⁸ μmol/L. The analysis of spiked food samples containing S-fenvalerate using the developed SERS sandpaper afforded excellent recoveries (92.2%−109.7%). Additionally, the SERS sandpaper was successfully applied to quantify S-fenvalerate in real food samples, with results consistent with analyses conducted using gas chromatography.

A reusable and flexible surface-enhanced Raman spectroscopy (SERS) sensor was constructed through an interfacial assembling strategy for rapid and non-destructive detection of bifenthrin in foods. The sensor was fabricated through rational integration of two components: (1) a plasmonic ternary Au@Cu₂O@Ag nanoarrays synthesized via liquid-liquid interface self-assembly (LLISA) on Teflon tape, and (2) an epoxy resin (EP) encapsulation layer. The Au@Cu₂O@Ag nanoarrays demonstrated exceptional SERS performance due to synergistic plasmonic enhancement effects from the Au core, charge transfer mediation via the Cu₂O interlayer, and secondary electromagnetic field amplification by the Ag shell. The Teflon tape ensured uniformity of the SERS “hot spots”, while EP encapsulation provided mechanical durability and oxidation resistance. Unlike traditional methods (e.g., HPLC, GC) requiring extensive pretreatment and hours-long analysis, the flexible SERS sensor allowed one-step and pretreatment-free sampling and on-site detection of bifenthrin on irregular food surfaces, delivering laboratory-grade quantification of bifenthrin within 3 minutes. Under optimal testing conditions, the sensor exhibited a low limit of detection (1.81 × 10^-9 μmol/L) and a wide linear response range of 10^-8-10³ μmol/L. Additionally, the flexible SERS sensor demonstrated high accuracy in bifenthrin-spiked food samples with recoveries of 94.18%-104.53%. Notably, the developed sensor exhibited practical applicability in bifenthrin quantification across four real food samples, demonstrating excellent agreement with standard gas chromatography (GC), thereby validating the reliability of the proposed method.

In this work, a highly sensitive electrochemical sensor based on Zn-doped copper gallium oxide@ordered mesoporous carbon (Zn-CuGaO₂@CMK-3) for signal amplification was successfully developed for the simultaneous detection of sunset yellow (SY) and tartrazine (TZ) in foods. Compared with CuGaO₂@CMK-3, Zn-CuGaO₂@CMK-3 offered enhanced conductivity and catalytic properties owing to the improved carrier density, which was beneficial to the electrooxidation of SY and TZ. Under the optimal testing conditions, the constructed Zn-CuGaO₂@CMK-3/GCE sensor offered a wide linear concentration range (0.25–100.00 μmol/L) for the detection of both SY and TZ. The limits of detection for SY and TZ were 0.044 and 0.059 μmol/L, respectively. Recovery experiments were performed in milk, white vinegar and biscuit samples, yielding satisfactory recoveries (82.70%–114.80%). Furthermore, the sensor was successfully applied to the determination of the SY and TZ residues in two kinds of carbonated drinks, and the results were nearly consistent with those detected by the high performance liquid chromatography (HPLC) method (P > 0.05).

In this study, a sandwich-type photoelectrochemical (PEC) aptasensor based on Cu₂MoS₄/CdS/In₂S₃ nanoclusters was resoundingly exploited for the detection of zearalenone (ZEN) in foods. Specifically, indium tin oxide (ITO) coated glass slides were decorated with Cu₂MoS₄/CdS/In₂S₃ and then ZEN aptamer-1 to create photoactive substrates (Cu₂MoS₄/CdS/In₂S₃-Apt1), with MoS₂ quantum dots modified with ZEN aptamer-2 (MoS₂ QDs-Apt2) serving as a PEC signal quencher. In the presence of ZEN, the close proximity of MoS₂ QDs-Apt2 to Cu₂MoS₄/CdS/In₂S₃-Apt1 created competition for light absorption and electron donors, resulting in a decrease in photocurrent but boosted detection sensitivity. The aptasensor that was constructed demonstrated a broad linear range (10^-5-10³ ng/mL) with a limit of detection (LOD) as low as 2.38 fg/mL. In addition, the aptasensor offered excellent stability, anti-interference properties, and practicality for ZEN detection in real food samples. This work offers a new approach for the ultrasensitive detection of harmful mycotoxins in foods.

In this work, a novel electrochemical sensor based on covalent organic framework@carbon black@molecularly imprinted polydopamine (COF@CB@MPDA) was developed for selective recognition and determination of ciprofloxacin (CF). COF@CB@MPDA possessed good water dispersibility and was synthesized by the self-polymerization of dopamine under alkaline conditions in the presence of the COF, CB and CF. The high surface area COF enhanced the adsorption of CF, whilst CB gave the composites high electrical conductivity to improve the sensitivity of the proposed COF@CB@MPDA/glassy carbon electrode (GCE) sensor. The specific recognition of CF by COF@CB@MPDA involved hydrogen bonding and van der Waals interactions. Under optimized conditions, the sensor showed a good linear relationship with CF concentration over the range of 5.0 × 10^–7 and 1.0 × 10^–4 mol/L, with a limit of detection (LOD) of 9.53 × 10^–8 mol/L. Further, the developed sensor exhibited high selectivity, repeatability and stability for CF detection in milk and milk powders. The method used to fabricate the COF@CB@MPDA/GCE sensor could be easily adapted for the selective recognition and detection of other antibacterial agents and organic pollutants in the environment.

In this work, a novel bifunctional zirconium dioxide@zeolitic imidazolate framework-90 (ZrO₂@ZIF-90) nanozyme was successfully developed for the catalytic degradation and electrochemical detection of methyl parathion (MP). The ZrO₂@ZIF-90 nanozyme with phosphatase hydrolysis activity can convert MP into p-nitrophenol (p-NP). The addition of ZrO₂ riched in Lewis acid Zr(Ⅳ) sites significantly enhanced the phosphatase hydrolysis activity of ZIF-90. ZrO₂@ZIF-90 also displayed satisfactory electrocatalytic performance on account of the high surface area, high porosity and powerful enrichment ability of the ZIF-90 and the excellent ion transfer capacity of ZrO₂. A ZrO₂@ZIF-90 nanozyme modified glassy carbon electrode (ZrO₂@ZIF-90/GCE) was then fabricated to analyze p-NP formed through MP degradation. Under the optimized conditions, the developed sensor displayed satisfactory analytical performance with a low limit of detection of 0.53 μmol/L and two wide linear ranges (3-10 and 10-200 μmol/L). ZrO₂@ZIF-90 nanozyme accomplished to the degradation and electrochemical detection of MP in river water and spiked fruits. This study identifies a promising new strategy for the design of bifunctional nanozymes for the detection of environmental hazards.

Herein, a novel interference-free surface-enhanced Raman spectroscopy (SERS) strategy based on magnetic nanoparticles (MNPs) and aptamer-driven assemblies was proposed for the ultrasensitive detection of histamine. A core-satellite SERS aptasensor was constructed by combining aptamer-decorated Fe₃O₄@Au MNPs (as the recognize probe for histamine) and complementary DNA-modified silver nanoparticles carrying 4-mercaptobenzonitrile (4-MBN) (Ag@4-MBN@Ag-c-DNA) as the SERS signal probe for the indirect detection of histamine. Under an applied magnetic field in the absence of histamine, the assembly gave an intense Raman signal at “Raman biological-silent” region due to 4-MBN. In the presence of histamine, the Ag@4-MBN@Ag-c-DNA SERS-tag was released from the Fe₃O₄@Au MNPs, thus decreasing the SERS signal. Under optimal conditions, an ultra-low limit of detection of 0.65 × 10^-3 ng/mL and a linear range 10^-2–10⁵ ng/mL on the SERS aptasensor were obtained. The histamine content in four food samples were analyzed using the SERS aptasensor, with the results consistent with those determined by high performance liquid chromatography. The present work highlights the merits of indirect strategies for the ultrasensitive and highly selective SERS detection of small biological molecules in complex matrices.