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A sensitive dual immunochromatographic test strip (dual-ICTS) was developed to detect malachite green (MG) and its metabolite, leucomalachite green (LMG), using two types of gold nanoparticles: round-shaped (red) and star-shaped (blue). The detection limits were determined to be 0.221 μg L−1 for MG and 0.214 μg L−1 for LMG, respectively. The dual-ICTS provided a cut-off value of 1.8 μg L−1 for MG and LMG detection. The dual-ICTS successfully detected MG and LMG in food samples, with recovery rates ranging from 86 % to 116 %. The dual-ICTS was evaluated by correlation analysis between the proposed assay and the well-established enzyme-linked immunosorbent assay in the MG and LMG detection. This is the first report on the development of the ICTS that can detect both MG and LMG at the same time within only 5 min, making it a sensitive and rapid tool for on-site detection. [Display omitted] • Two colored gold nanoparticles were applied as dual - color labels in ICTS. • A novel dual-ICTS was fabricated for simultaneous detection of MG and LMG. • The dual-ICTS provided a cut-off value of 1.8 μg L−1 for MG and LMG detection. • ICTS is a rapid, for on-site simultaneous detection for MG and LMG within 5 min. [ABSTRACT FROM AUTHOR]

[Display omitted] • Julolidine-coumarin based probes with varying electron acceptor unit was synthesized. • The probes displayed a striking color change when exposed to cyanide ions. • To enable real-time analysis, an Arduino electronic device was developed. • The sensor system can detect cyanide ion in food and water samples. A highly efficient system that incorporates the instantaneous visualization of the cyanide ion in water was synthesized by keeping the fluorophore system (electron donor) as a julolidine-coumarin conjugate and changing the electron acceptor unit. The probes exhibit a notable color change in normal and UV light. The probe interaction modalities are based on the ICT process. With a detection limit in the nM range, it may preferentially react with cyanide, which is less than the tolerable level of 1.9 μM. According to 1H NMR data, the probes detect cyanide ions by nucleophilic addition reaction mechanism. Furthermore, current probe successfully determines real resources, including cyanide containing cassava powder, sprouted potatoes and various water samples. Besides the test strips, an electronic Arduino device was also employed to detect the cyanide ion. As such, the developed probes exhibit outstanding practical application with respect to the cyanide ion. [ABSTRACT FROM AUTHOR]

In this study, we present a new approach utilizing Au nanodendrites (Au NDs) to modify flexible screen-printed carbon electrodes (FSPCEs), offering an efficient platform for voltammetric sensing of nitrite ions in food samples. The FSPCEs are created with gold leaf-like nanodendrites through a simple, one-step electrochemical deposition process. The direct growth of these Au NDs occurs efficiently on the carbon-paste electrode, eliminating the need for binders or additional reducing agents and organic solvents, owing to the aforementioned matrix. The modified electrodes serve as promising sensing platforms for nitrite detection. The outcomes demonstrated that a significant amount of AuNPs with dendritic morphologies were dispersed throughout the FSPCE.These novel flexible electrodes act as effective electrocatalyst for NO 2 − oxidation due to their large electrochemical active surface area (ECSA), well-dispersed Au nanostructures, and high electrical conductivity. The optimized sensor exhibits a wide linear response range from 0.02 to 5.8 µM, with 1.0 nM limit of detection, an impressive sensitivity of 52.529 µA µM−1 cm−2 and a quick current response time (< 3 s) towards nitrite ions. Additionally, the suggested sensor demonstrates high selectivity, reproducibility, and stability. Furthermore, the FSPCEs are evaluated for their ability to selectively detect nitrite ions in various food samples such as tap water, drinking water, milk, and fruit juices, comparing the results with standard methods in real sample analysis. The fabricated sensors show promising potential for practical applications in food and environmental analysis. Consequently, Au NDs@FSPCE electrode emerged to be a novel platform for NO 2 − electrochemical detection. Because of their great affinity for analytical substances in solutions, gold nanodendrites supported on flexible screen-printed carbon electrodes (FSPCEs) are very useful for electrode modifications. Their increased effective surface area, which greatly raises the electrode's sensitivity and specificity for a range of analytical applications, is responsible for their high affinity. [Display omitted] [ABSTRACT FROM AUTHOR]

Food adulterants are substances added to food products to improve their weight and appearance and reduce costs. However, the use of these substances deteriorates the quality of food products and results in a decrease in nutritional value. For this reason, situations that negatively affect the health of consumers occur. Microfluidic paper-based analytical devices (μPADs) have gained popularity as miniaturized, portable, highly sensitive, accurate, and affordable detection platforms. μPADs are preferred as advantageous platforms for the determination of food adulterants in foods, thanks to their on-site analysis and simultaneous determination of multiple analytes features. Therefore, μPADs provide fast and reliable results in food safety. In this review, the selection of paper and method for the fabrication of μPADs, as well as the determination of the signal readout mode, are briefly mentioned. In addition, the sample preparation process before the use of PADs is also mentioned. The most current applications of μPADs in determining food adulteration are applied sample, method, linear range, LOD, etc., evaluated in terms of parameters. This review also sheds light on commercial practices by discussing the most prominent studies in the last three years. • μPAD-based analytical device approaches for the detection of food adulteration. • A comprehensive overview of food adulteration practices. • The place of μPADs in food applications. • Extensive investigation to produce of μPADs. [ABSTRACT FROM AUTHOR]

Sulfur dioxide and its derivatives (HSO 3 −/SO 3 2-) play a crucial role in maintaining the redox balance of biological systems. Therefore, the development of effective detection methods for sulfur dioxide and its derivatives is of paramount importance. Herein, a novel fluorescent probe, QLN , was designed and synthesized using small molecule quinoline, demonstrating the capacity to recognize HSO 3 − through Michael addition reaction. The probe QLN displayed good selectivity and anti-interference capabilities for HSO 3 − recognition, effectively operating within a wide pH range (5–9) and exhibiting a rapid response time (<5 s). Practical applications revealed the potential of probe QLN for detecting HSO 3 − in living cells and food samples. A new fluorescence 'turn-on' probe QLN for HSO 3 − recognition in an aqueous media utilizing ICT effect has been developed. [Display omitted] • Probe QLN has high selectivity and sensitivity for the detection of HSO 3 −. • Probe QLN can detect HSO 3 − via color deepening and fluorescence "turn on" dual response. • Probe QLN can be attached to silica gel plate for qualitative detection of SO 2 gas. • Probe QLN can be based on hydrogel-based kits to detect the content of HSO 3 − in food samples. • Probe QLN can image endogenous and exogenous HSO 3 − in MCF-7 cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • NIR photothermal lens spectrometer (PTLS) used for determination phosphate ions. • NIR PTLS is highly sensitive to phosphate with the detectability amount to 33 pg. • Phosphate ions can be analyzed by using PTLS in beverage and blood serum samples. • NIR PTLS with microfluidic cell can be used for phosphate detection in 50 µL samples. In this work, photothermal lens spectrophotometer (PTLS) with crossed-beam configuration pumped by a laser diode (850 nm) was used for determination of soluble phosphorus exists mainly in the form of orthophosphate (PO 4 3−) in nonalcoholic beverage and human blood serum samples. The determination was carried out after complexation reaction between blue molybdenum and phosphate in aqueous solution. UV–vis spectrophotometry was used by measuring absorption in the near infrared region (815 nm) for optimizing the complex formation time, concentrations of reducing agent and sulfuric acid. The UV–vis absorption measurements showed that the calibration curve was obtained in the concentration ranges of 0.5–80 mg L−1 with a linear correlation coefficient of 0.98 and a detection limit of 0.2 mg L−1. Then, PTLS at a wavelength of 850 nm after optimizing the device conditions (flow rate, excitation laser power and interrupting frequency) was used for phosphate determination. The calibration curve in the concentration range of 11–1000 µg L−1 has a correlation coefficient of 0.98 and a detection limit of 4 µg L−1. The achieved detection limit was about 50 times better than NIR absorption spectrometry using a conventional 1 cm sample cell. In PTLS with the 3 μL microfluidic cell experimental detectability amount of phosphate is 33 picogram, while in UV–vis-NIR method this amount is 1.5 µg. [ABSTRACT FROM AUTHOR]

[Display omitted] • Quasi-hydrophobic DES for simultaneous extraction of polar and non-polar analytes. • Wide range of mathematical models to confirm experimental results. • Quasi-hydrophobic DES provide versatility in the extraction of a wide range of dyes. • The first automated procedure for determination of polar and non-polar dyes. In this work, quasi-hydrophobic deep eutectic solvents were used for the first time for the efficient extraction of both polar (Sunset Yellow FCF (E 110), Azorubine (E122), Ponceau 4R (E124)) and non-polar (Sudan I, Sudan II, Sudan III) dyes from food products at the same time. These solvents were made from polar and nonpolar components, which made it possible to extract analytes of various natures. To automate the technique, a flow analysis method was used, which increases the speed and reliability of determining analytes in food samples. For a detailed study of extraction mechanisms, various process modeling methods were used. The proposed DES-based method addresses the limitations of traditional extraction methods, offering a more robust and efficient solution for food analysis. Validation of the method has demonstrated high precision, accuracy and extraction efficiency, making it a promising tool for regulatory compliance and consumer safety in the food industry. The following analytical characteristics were achieved: the limits of detection were 0.03–0.13 mg L−1, limits of quantification were 0.09–0.44 mg L−1, an extraction recovery exceeding 85 %, a linear range was from 1 to 100 mg L−1, and a relative standard deviation ranging from 2 % to 10 %. The experiments were confirmed by both Conductor Like Screening Model-Segment Activity Coefficient (COSMO-SAC) and the Non-Covalent Interaction using the Reduced Density Gradient of the DES-dye system in aqueous media. [ABSTRACT FROM AUTHOR]

The emission of venenous sulfur dioxide (SO 2) and its derivatives from industrial applications such as coking, transportation and food processing has caused great concern about public health and environmental quality. Probes that enable sensitivity and specificity to detect SO 2 derivatives play a crucial role in its regulations and finally mitigating its environmental and health impacts, but fluorescent probes that can accurately, rapidly and on-site detect SO 2 derivatives in foodstuffs and environmental systems rarely reported. Herein, a near-infrared (NIR) fluorescent probe (ZTX) for the ratiometric response of bisulfite (HSO 3 −) was designed and synthesized by regulating the structure of high-performance HSO 3 − fluorescent probe SL previously reported by us based on structural analyses, theoretical calculations and related literature reports. The Michael addition reaction between the electronic-deficient C=C bond and HSO 3 − destroys ZTX 's π-conjugation system and blocks its intramolecular charge transfer (ICT) process, resulting in a significant fading of the fuchsia solution and the bluish-purple fluorescence turned light blue fluorescence. Fluorescent imaging of HSO 3 − in live animals utilizing ZTX has been demonstrated. The quantitative analysis of HSO 3 − in food samples using ZTX via a smartphone has been also successfully implemented. Simultaneously, the ZTX -based test strips were utilized to quantificationally determine HSO 3 − in environmental water samples by a smartphone. Consequently, probe ZTX could provide a new method to understand the physiopathological roles of HSO 3 −, evaluate food safety and monitor environment, and is promising for broad applications. [Display omitted] • The fluorescence probe ZTX features NIR-emitting (849 nm), large Stokes shift (326 nm) and high biocompatibility. • The quantitative determination of HSO 3 − in environmental water and actual food sampleswere realized using ZTX combined with a smartphone. • Applications of ZTX in fluorescence imaging of HSO 3 − in vivo in mouse model are successfully demonstrated. [ABSTRACT FROM AUTHOR]

In this study, we demonstrated an approach for the development of multiplex immunochromatographic test strip (MICS) for neomycin (NEO), penicillin (PEN), and chloramphenicol (CAP) detection using three different-colored gold nanoparticles. The gold nanoparticles: gold nanospheres (red), gold nanostars (blue), and gold nanoflowers (black) were applied as labels for MICS fabrication. The proposed MICS achieved a clearly visible limit of detection with cut-off values of 500, 5, and 0.5 μg L−1 for NEO, PEN, and CAP, respectively within only 10 min. Such smartphone-based detection provided a limit of detection of 3.70 μg L−1 for NEO, 0.10 μg L−1 for PEN, and 0.008 μg L−1 for CAP. The analysis of real samples by the developed MICS was well correlated with the enzyme-linked immunosorbent assay and liquid chromatography–mass spectrometry. The proposed MICS has the potential to be used for the simultaneous detection of NEO, PEN, and CAP with rapid, precise, and sensitive results. [Display omitted] • Three shaped AuNPs as red, blue, and black colored labels were applied for MICS fabrication. • A novel MICS was developed for simultaneously detecting NEO, PEN, and CAP within 10 min. • The proposed MICS could analyze the food samples in easy, rapid, on-site and cost-effective. [ABSTRACT FROM AUTHOR]

In the present study, a selective electrochemical technique to determine Zineb fungicide based on molecularly imprinted polymer (MIP) as a simple and fast method was developed. The MIP was synthesized on a glassy carbon electrode (GCE) modified with single walled carbon nanotube (SWCNT) through electropolymerization of ortho-aminophenol (o-AP) monomer and Zineb fungicide analyte. Some ions and compounds were examined as the interfering species to investigate the selectivity of the developed sensor. This research proposes simple determination of Zineb fungicide with a linear range 5–1000 fM and limit of detection (LOD) 1.6 fM. Finally, this strategy was successfully used to detect Zineb in some vegetable and fruit samples such as cucumber, potato, tomato, lettuce, peach, and apple with a satisfactory recovery range between 98.85 and 102.00%. The obtained results indicated that the newly developed method is stable, convenient, and has easy preparation steps with low-cost materials. It can be used for rapid diagnosis of Zineb in crops and agriculture products, which holds great promise in detection of environmental pollutants. • The detection of Zineb fungicide using MIP was reported for the first time. • The MIP was synthesized by electropolymerization on the GCE modified with SWCNT. • MIP/SWCNT/GCE provided a good linear range and low LOD towards Zineb. • The modified electrode was successfully applied in food samples. • Sensor performs well in selectivity, stability, repeatability, and reproducibility. [ABSTRACT FROM AUTHOR]

[Display omitted] • A dual-response fluorescent probe RPT for detecting SO 2 and HClO is synthesized. • The fluorescent probe can monitor SO 2 and HClO with a wavelength difference of 85 nm. • The fluorescent probe has simple synthetic method and is easy to be obtained. • Fluorescent probe can image SO 2 and HClO in living cells (HeLa and RAW 264.7 cells). • Fluorescent probe can detect SO 2 and HClO in various water and food samples. Hypochlorous acid (HClO) and sulfur dioxide (SO 2) play vital roles in various fields, including living organisms, water samples, food and so on. High doses of SO 2 and HClO are seriously harmful to human and are associated with a variety of diseases. Therefore, monitoring the level of SO 2 and HClO in various fields is significant for exploring their roles. In this work, a novel dual-response fluorescent probe RPT for detecting SO 2 and HClO is successfully designed and synthesized, which is composed by pyrylium moiety and thiazine part. The fluorescent probe RPT can respectively monitor SO 2 and HClO by two well-separated emission wavelength with an obvious difference of 85 nm. The fluorescent probe RPT also displays desired properties such as simple synthetic method, high sensitivity and selectivity. In addition, as a biocompatible molecule, RPT has been successfully used for monitoring SO 2 and HClO in HeLa cells and RAW 264.7 cells in two different channels (red channel and green channel). More importantly, SO 2 and HClO levels in various water and food samples have been detected with satisfactory results. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple and fast-responsive fluorescent chemosensor BTP was developed for S2-. • BTP featured high sensitivity and specificity for S2- via fluorescent color change. • BTP was applied to real water, test strips, and food systems to detect S2-. • BTP is first applied to trace food spoilage among benzothiazole-based S2- probes. • Detecting mechanism of S2- by BTP was demonstrated to be deprotonation of phenol. The detection of S2− is required because of its harmful effects on human health. This led us to strategically design a new benzothiazole-based fluorescent chemosensor BTP (2-(benzo[d]thiazol-2-yl)-4,6-dichlorophenol). This sensor undergoes a fluorescence color change from orange to green in the presence of S2− via the deprotonation of phenol in near-perfect water. The detection limit for S2− reached 0.78 μM and BTP could selectively probe S2− over other competing analytes. The process whereby BTP responds to S2− was suggested to be improved intramolecular charge transfer (ICT), as was demonstrated by extensive DFT calculations. Particularly, BTP was successfully applied to detect S2− in zebrafish, real water, and beverage samples. Further, test strips coated with BTP were used to monitor the S2− released in raw meat. BTP is the first benzothiazole-based chemosensor developed to detect the S2− released from various types of food samples. The proposed method offers a novel tool for measuring S2− in biological and environmental systems, as well as the food quality under on-site conditions. [ABSTRACT FROM AUTHOR]

A comprehensive overview of bisphenol endocrine disruptors in food and the related sample pretreatment techniques and analytical methods for food analysis were presented. [Display omitted] • Bisphenols have wide applications in our life. • Bisphenols have chronic and acute toxicity for organisms and humans, such as endocrine disruption, estrogen syndrome, carcinogenicity and so on. • This article summarizes and discusses the physicochemical properties, applications and hazards of bisphenols. • Efficient pretreatment and analytical methods used for detecting bisphenols in various foods are emphasized. • This article predicted the challenges and research directions for bisphenols in the future. Bisphenols (BPs) are organic compounds commonly found in resins and plastics used for food packaging, tableware, bottle tops, water pipes, and epoxy coatings in metal cans. BPs can migrate from these materials into food, leading to human exposure and bioaccumulation. Many BPs have been found to have endocrine-disrupting and other toxic effects, causing adverse health effects and raising concerns about food safety worldwide. Sensitive and accurate detection of BPs can effectively avoid their hazards, which is one of important measures to improve food safety. However, food sources are wide, food matrices are complex, the structures of BPs are diverse, and their content are very low. It is necessary to remove most matrices and interfering substances to enrich BPs from food samples. At the same time, rapid, sensitive and efficient detection of BPs is also very important for food safety. Therefore, sample pretreatment techniques and detection methods play crucial roles in monitoring bisphenol endocrine disruptors in foods. This article discusses sample pretreatment techniques and analytical assays used for bisphenol endocrine disruptors in foods. The aim is to provide research ideas for the development of new techniques and methods. The article summarises and discusses the physicochemical properties, applications, and hazards of BPs. Furthermore, this text predicts future challenges and research directions for BPs. These include internal exposure levels and health effects, toxicity mechanisms, novel sensors, and eco-friendly food packaging materials. [ABSTRACT FROM AUTHOR]

Cys plays significant roles in food industries. It is very necessary to on-site quantify Cys content in food samples. Herein, we rationally developed a fluorescent sensor, YF , for on-site measurement of Cys in various foodstuffs. Sensor YF showed fluorescence response to Cys in near infrared (NIR) region, which could dramatically mitigate the interference of autofluorescence in foodstuffs. Moreover, sensor YF exhibited obvious colorimetric change to Cys. Accordingly, the sensor YF was capable of detecting Cys via both fluorescence method and colorimetric method, making the detection more reliable. Sensor YF also presented high selectivity and sensitivity to Cys, and its detection limits was measured to be 88 nM. The practical application demonstrated that sensor YF was able to monitor Cys in live cells and zebrafish via fluorescence imaging. Moreover, variations of Cys concentration in spinach leaves under different Cd2+ stress were effectively tracked. To accomplish on-site quantitation of Cys content in foodstuffs, a simple and portable measuring device was made. Sensor YF and the portable measuring device were successfully utilized for quantitation of Cys in food samples such as dry red pepper, tomato and soy bean. The detection method established herein will be conveniently employed for on-site quantitation of Cys in various food samples. [Display omitted] • A novel fluorescent sensor for detecting Cys via both NIR fluorescence method and colorimetric method has been developed. • To accomplish on-site quantitation of Cys level in food samples, a simple and portable measuring device was made up. • The sensor and portable measuring device were firstly applied for on-site quantitation of Cys in various food samples. [ABSTRACT FROM AUTHOR]

90Sr and 210Pb are considered to be key radionuclides in internal exposure resulting from dietary intake, however, the established methods employed for their detection are time-comsuming. A method for the sequential separation of 90Sr and 210Pb using a Sr·spec resin by LSC measurement is developed, which is highly suitable for food safety monitoring as its minimal sample requirements. The sequential separation of Sr and Pb from the sample was using 0.05 mol/L HNO 3 and 0.05 mol/L C 6 H 5 O 7 (NH 4) 3. The chemical recoveries of Sr and Pb measured using ICP-OES were 72–83% and 80–88%, respectively. The minimum detectable activities of 90Sr and 210Pb in the food sample were 36.2 mBq/kg and 28.6 mBq/kg, respectively, obtained from a 0.1 kg fresh sample and 300 min counting time. The method was validated using reference materials and compared with other methods. The feasibility of the developed method for other highly complex food matrices needs further investigation. • Sequential separation of 90Sr and 210Pb in food samples using Sr.spec resin, measured by LSC. • The chemical recoveries of Sr and Pb were 72–83% and 80–88%, respectively. • The MDA of 90Sr and 210Pb were 36.2 mBq/kg and 28.6 mBq/kg, respectively. • The method was validated by reference materials and compared to other methods. [ABSTRACT FROM AUTHOR]

Sulfite, widely used in food and pharmaceutical industries, poses significant health and safety concerns, necessitating efficient detection methods. This study introduces three novel red fluorescent probes (MCC-BT, MCC-TI, and MCC-DM), synthesized by integrating chromene derivatives with various electron-withdrawing groups. These probes effectively detect sulfite in both food samples and living cells, leveraging a mechanism transition from intramolecular charge transfer (ICT) to photo-induced electron transfer (PET). They demonstrate low detection limits (2.0 μM, 0.42 μM, and 0.34 μM, respectively) and offer advantages including large Stokes shifts, minimal interference, and colorimetric capabilities. We also developed smartphone-compatible test paper strips for convenient sulfite detection in real-world samples. The probes' effectiveness is further evidenced through sulfite quantification in Traditional Chinese Medicine ingredients. Additionally, their robust fluorescent imaging potential for cellular sulfite sensing highlights their significant contribution to analytical chemistry and biomedical research. • Three probes exhibit red fluorescence with exceptional sensitivity, outstanding selectivity, and large Stokes shifts. • Portable detection of sulfite in real samples is achieved using a smartphone. • Quantification of sulfite levels is performed in Traditional Chinese Medicine ingredients samples. • These probes can be employed for real-time monitoring of sulfite in living cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of gold nanoclusters (AuNCs-CCY) using peptides as templates. • The fluorescence of R6G was quenched by gold nanocluster (AuNCs-CCY). • Once introduced, Pb2+ triggered the reversion of quenched fluorescence. • Sensitive and selective detection of Pb2+ is achieved by regulating the FRET effect. • This detection method simplifies operational procedures, achieve rapid detection, and reduces associated costs. Lead pollution has remained a significant global concern for several decades due to its detrimental effects on the brain, heart, kidneys, lungs, and immune system across all age groups. Addressing the demand for detecting trace amounts of lead in food samples, we have developed a novel biosensor based on fluorescence resonance energy transfer (FRET) from fluorescein R6G to gold nanoclusters (AuNCs-CCY). By utilizing polypeptides as a template, we successfully synthesized AuNCs-CCY with an excitation spectrum that overlaps with the emission spectrum of R6G. Exploiting the fact that Pb2+ induces the aggregation of gold nanoclusters, leading to the separation of R6G from AuNCs-CCY and subsequent fluorescence recovery, we achieved the quantitative detection of Pb2+. Within the concentration range of 0.002–0.20 μM, a linear relationship was observed between the fluorescence enhancement value (F-F 0) and Pb2+ concentration, characterized by the linear equation y = 2398.69x + 87.87 (R2 = 0.996). The limit of detection (LOD) for Pb2+ was determined to be 0.00079 μM (3σ/K). The recovery rate ranged from 96 % to 104 %, with a relative standard deviation (RSD) below 10 %. These findings demonstrate the potential application value of our biosensor, which offers a promising approach to address the urgent need for sensitive detection of heavy metal ions, specifically Pb2+, in food samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new near-infrared fluorescent probe HR for specially responses toward H 2 S was synthesized. • Probe displays a colormetric and NIR fluorescent response toward H 2 S with large Stokes shift, high selectivity and sensitivity. • Probe can be applied for sensing detection of H 2 S in food spoilage and living cells. Hydrogen sulfide (H 2 S), as a biomarker signaling gas, is not only susceptible to food spoilage, but also plays a key function in many biological processes. In this work, an activated near infrared (NIR) H 2 S fluorescent probe was designed and synthesized with quinoline-conjugated Rhodols dye as fluorophore skeleton and a dinitrophenyl group as the responsive moiety. Due to the quenching effect of dinitrophenyl group and the closed-loop structure of Rhodols fluorophore, probe itself has a very weak absorption and fluorescence background signal. After the H 2 S-induced thiolysis reaction, the probe exhibits a remarkable colormetric change and NIR fluorescent enhancement response at 716 nm with large Stokes shift (116 nm), and possesses high sensing selectivity and sensitivity with a low detection limits of 330 nM. The response mechanism is systematically characterized by 1H NMR, MS and DFT calculations. The colorimetric change allows the probe to be used as a test strips to detect H 2 S in food spoilage, while NIR fluorescent response helps the probe monitor intracellular H 2 S. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple method for simultaneous recognition of d / l -Carn was investigated. • d / l -Carn were mobility separated by their ternary diastereomeric complex by adding Nat and meal ions. • Metal ions in group IA (Li+, Na+, K+, Rb+, Cs+) have separation effects. • Theoretical calculations were performed to elucidate the enantiomeric separation at the molecular level. • The proposed method was applied to l / d -Carn detection in beverage samples and fresh pork. This work presents a straightforward approach to the separation d / l -carnitine (d / l -Carn) using ion mobility–mass spectrometry (IM-MS) and theoretical calculations. Natamycin (Nat) was used as separation reagent to interact with the Carn, metal ions (G) were employed as ligand, the resultant ternary complexes [ d / l -Carn + Nat + G]+ were observed experimentally. IM-MS results revealed that d / l -Carn could be baseline separated via complex formation using Li+, Na+, K+, Rb+, and Cs+, with a maximum peak separation resolution (R p-p) of 2.91; Theoretical calculations were performed to determine the optimal conformations of [ d / l -Carn + Nat + Li/K]+, and the predicted collisional cross section values were consistent with the experimental values. Conformational analysis was used to elucidate the enantiomeric separation of d / l -Carn at the molecular level via the formation of ternary complexes. Furthermore, quantitative analyses for the determination of the enantiomers were established with effective linearity and acceptable sensitivity. Finally, the proposed method was successfully applied in the determination of d / l -Carn in food samples. [ABSTRACT FROM AUTHOR]

A new dual-responsive chemosensor NOP (4-(7-nitrobenzo[ c ][1,2,5]oxadiazol-4-yl)piperazin-1-yl)(pyrazin-2-yl)methanone) was synthesized. Chemosensor NOP selectively probed S2- via fluorescent turn-off and colorimetric change from yellow to pink in pure water. The detection limit of NOP for S2- was determined to be 1.22 μM (fluorescence) and 1.05 μM (colorimetry), which were much below the WHO standard (14.8 μM). The detection mechanism of S2- was illustrated to be thiolysis reaction of NBD-amine moiety by 1H NMR titrations, ESI-mass, and DFT calculations, producing the cleavage product (NBD-S-). NOP could successfully quantify S2- in water, beverage samples, and zebrafish. Practically, NOP -coated strips could be employed for easy and rapid recognition of S2- in real-field and for monitoring food spoilage by dual-response. Therefore, NOP assured an auspicious approach for reliable S2- detection in real-field and food systems. [Display omitted] • New dual-responsive chemosensor NOP was synthesized for detection of S2- in water. • NOP selectively detected S2- through fluorescent turn-off and colorimetric change. • NOP is the first case to trace food spoilage among dual-responsive sensors for S2-. • NOP can quantify S2- in water, beverage samples, and zebrafish. • Detecting mechanism of S2- by NOP was proposed to be the thiolysis of NBD amine. [ABSTRACT FROM AUTHOR]

[Display omitted] • The quercetin was detected using the electrochemical sensing method. • The PrV@g-CN composite was prepared by the hydrothermal method. • The synergetic effect between the PrVO 4 and g-CN enhanced the detection of Qc. • The PrV@g-CN shows a linear range of 0.05–252.0 µM and LOD 0.002 µM of towards Qc. • The proposed sensor was applied for Qc detection in green and black tea samples. Flavonoids or phenolic compounds are part of the daily intake of every human being. Though they are positive traders for metabolism, excessive intakes bring about detrimental impacts on human health. Herein, the anti-cancer capacitive nature quercetin (Qc) was electrochemically detected through the rare earth metal-based sphere like praseodymium vanadate (PrVO 4) entrapped graphitic carbon nitride (g-CN) as electrode modifiers. The nanocomposite was prepared by the one-pot hydrothermal method and characterized by phase compositional and morphology-based techniques. The existing synergistic nature between the PrV@g-CN (praseodymium vanadate@graphitic carbon nitride) makes them have an enhanced electrochemical response towards the Qc than the individual material. The obtained cyclic voltammogram and differential pulse voltammogram profile show one major oxidation peak which is attributed to the conversion of quercetin to quercetin-o-quinone. The PrV@g-CN/GCE (GCE- glassy carbon electrode) shows a good electrochemical active surface area (A = 110 cm2) and linear range between 0.05 and 252.00 μM with a LOD (limit of detection) of 0.002 µM. Moreover, the PrV@g-CN/GCE exhibits good current retention (94.76 %) around 14 days and appreciable repeatability (RSD- 0.5 %) and reproducibility (RSD- 1.3 %) towards the Qc. The real-time implementation of the proposed sensor exhibits a good recovery range towards the black tea (95.00–98.10 %) and green tea (97.80–99.60 %). [ABSTRACT FROM AUTHOR]

Unmodified hairy basil seed mucilage (Ocimum basilicum L.), with attractive features as structural functionality and adsorption capacity, was employed as a green biosorbent for dispersive solid phase extraction and enrichment of oxytetracycline, tetracycline, and doxycycline before quantitation by HPLC-UV for the first time. Hairy basil crushed seed increased the contacting surface area and was completely dispersed in the sample solution to extract tetracyclines under acidic condition with the assistance of ultrasonic waves. The analytes in the extraction phase were separated on a C 18 column under isocratic condition with a mobile phase consisted of acetonitrile and trifluoroacetic acid. Influence of chemical and physical variables on the extraction efficiency of the developed method was investigated and optimized systematically. Under the optimal condition of all experimental parameters, good linear ranges were obtained at 15.0–500 μg L−1 for tetracyclines with determination coefficients more than 0.9994. Limits of detection (LODs) and limits of quantitation (LOQs) ranged 5.0–7.0 and 15.0 μg L−1, respectively. Relative standard deviations (RSDs) of the proposed method at 100 and 300 μg L−1 for TCs were less than 13 % and 10 %, respectively with percentage TC recoveries from spiked standard ranging 83.1–109.9 %. This simple, reliable, cost-effective, and environmentally friendly method was successfully applied for the analysis of tetracycline residues in milk. The greenness of the proposed method was assessed using the Analytical Eco-Scale and AGREE protocol. [Display omitted] • Unmodified HBSM was used as a green biosorbent for DSPE for the first time. • Alternative DSPE based on biosorbent was utilized to enrich TC residues in milk. • UAE was synergized with DSPE to enhance extraction efficiency. • After preconcentration using the developed method TCs were quantified by HPLC-UV. • This method is simple, reliable, cost-effective, and environmentally friendly. [ABSTRACT FROM AUTHOR]

With the merits of non-destructive, high penetration ability and minimizing autofluorescence, near-infrared (NIR) fluorescent probes have attracted much attention. In this paper, a NIR emission fluorescent turn-on probe THQ-L for H 2 S was synthesized by the knoevenagel condensation between tetrahydroquinoxaline-6- formaldehyde derivative and 2-benzothiazoleacetonitrile. THQ-L can recognize H 2 S through tandem reaction triggered by HS− to construct 1,4-diethylpiperazine-modified iminocoumarin-benzothiazole, which produces a strong red fluorescent signal. THQ-L displayed an excellent selectivity toward H 2 S, a large stokes shift (126 nm), a high signal-to-noise ratio (200-fold), the detection limits of 38.3 nM in PBS (10 mM, pH 7.4, 30% THF). The application study indicates that THQ-L can sensitively detect H 2 S in red wine, natural waters, living cells and can be prepared for a test paper strip for the qualitative detection of H 2 S. Image 1 • A novel NIR fluorescent probe for H 2 S based on tandem reaction to construct iminocoumarin-benzothiazole. • TCF-DNs detects H 2 S with a large Stokes shift, a high signal-to-noise ratio, a low detection limit. • TCF-DNs can detect H 2 S in red wine, natural waters, and image H 2 S living cells. • TCF-DNs was prepared for test strip and was used for the qualitative detection of H 2 S. [ABSTRACT FROM AUTHOR]

• A highly selective fluorescent probe TPE-O for HSO 3 − detection has been developed. • TPE-O showed ultrafast fluorescence and colorimetric dual response to HSO 3 −. • TPE-O can detect the content of HSO 3 −in sugar and wine samples. • TPE-O can be loaded on agarose hydrogel to detect SO 2 gas. SO 2 is one of the main components of air pollution gas, its derivatives HSO 3 − and SO 3 2− were considerable used as food additive because of their antiseptic and bacteriostatic effects. Excessive intake of HSO 3 − is harmful to human health, so it is extremely important to detect the content of HSO 3 − in food sample by effective method. In this work, a small molecular fluorescence probe TPE-O based on tetraphenylethene fluorophore was designed and synthesized. The probe showed ultrafast (< 3 s) and obvious colorimetric response to HSO 3 − with high selectivity and sensitivity (LOD = 210 nM). The possible Michael-type addition of HSO 3 − on the activated C = C bond blocked the π-conjugated system, thus lead to changes in fluorescence and absorption spectra. Probe TPE-O not only can detect the content of HSO 3 − in sugar and wine, but also can be loaded on agarose hydrogel to detect SO 2 gas. Therefore, this work provided a powerful tool for the detection of HSO 3 − in food samples and SO 2 gas. [Display omitted] [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Centrifuge-less DES based magnetic nanofluid-linked air-agitated liquid–liquid microextraction. • A new generation of green solvents as DESs based magnetic nanofluid was introduced. • Toxic heavy metals of Cd, Pb, Cu, and As were analyzed in water, and food samples. • High potential of CL-DES-MNF-AALLME for application in complex matrices. Abstract In this research, the novel environmentally-friendly analytical method, Centrifuge-less deep eutectic solvent based magnetic nanofluid-linked air-agitated liquid–liquid microextraction (CL-DES-MNF-AALLME) coupled with ETAAS was proposed for simultaneous preconcentration of heavy metals of lead, arsenic, cadmium, and copper. In CL-DES-MNF-AALLME, the extraction solvent is novel magnetic nanofluid consists of DES based magnetic multiwall carbon nanotubes which can easily be separated from the media with no need to centrifugation. The detection limits of 4.2, 3, 3.5 and 3.6 ng L−1 were acquired for cadmium, lead, copper, and arsenic respectively. The proper closeness of enrichment factors in the range of 635–644.5 to preconcentration factor (640), confirm the quantitatively of the proposed extraction method with relative standard deviation of 2.5–3.1(%) (n = 7). The potential of the CL-DES-MNF-AALLME was considered in walnut, rice, tomato paste, spinach, orange juice, black tea, and water samples which showed high capability of the proposed method for application in the complex matrixes. [ABSTRACT FROM AUTHOR]

Highlights • A solvent microextraction method was developed to sub ppb detection of acrylamide. • Derivatization was performed using HBr and (NH 4) 2 S 2 O 8 without use of toxic Br 2. • The consumption of derivatization and extraction reagents was at micro amount. Abstract A single-drop microextraction method followed by gas chromatography-electron capture detection was developed to determine acrylamide in food samples. Acrylamide was extracted by water and derivatized by hydrobromic acid in the presence of ammonium peroxydisulfate. The derivatization was carried out at 45 °C in 15 min using 46 µL of hydrobromic acid and 98 mg of ammonium peroxydisulfate. A 3.0-mL volume of the derivatized analyte was extracted using a 1.0-µL n -octanol droplet hanging from the needle tip of a GC microsyringe. After extraction, the extract was injected into the gas chromatograph. The influence of experimental parameters effective on derivatization reaction yield and extraction performance was studied. The limit of detection and quantification, relative standard deviation and linearity of the method were 0.60 µg/L, 2.0 µg/L, <6.0%, and 2.0–100.0 µg/L, respectively. The method was utilized to determine acrylamide in three food samples (i.e., bread, potato chips and cookie). [ABSTRACT FROM AUTHOR]

[Display omitted] • A colorimetric and ratiometric fluorescent probe TPA-Y with AIE characteristic has been developed; • TPA-Y exhibits a large emission peak separation up to 185 nm and gives low LOD (47.1 nM) for bisulfite; • Quantitative detection of bisulfite in food samples (sugar and red wine) was achieved; • TPA-Y can reversible response to HSO 3 -/H 2 O 2 cycles and cell imaging. Reversible detection of bisulfite (HSO 3 -) and hydrogen peroxide (H 2 O 2) is highly desirable in biology and food safety owing to their redox pair function in biological systems and their utilization in food industry. In this work, a ratiometric fluorescent probe (TPA-Y) with aggregation-induced emission (AIE) properties based on triphenylamine fluorophore was designed and synthesized for reversibly monitoring of HSO 3 -/H 2 O 2. Reaction of HSO 3 - with TPA-Y can result in ratiometric fluorescence changes (I 444 / I 629), and the emission spectrum blue shift reaches 185 nm, which can effectively avoid spectral overlap. Meanwhile, the solution color changed obviously from orange to colorless, enabling naked eye detection of HSO 3 -. TPA-Y was capable of quantitatively detect HSO 3 - in sugar and wine samples with the recovery rates ranging from 94.52 to 102.18%. In addition, TPA-Y is suitable to prepare paper strips and anti-counterfeiting ink for HSO 3 - detection. In addition, the original TPA-Y can be released after the addition product (TPA-Y-HSO 3 -) is oxidized by H 2 O 2 , and the HSO 3 -/H 2 O 2 redox cycle can repeat for at least six times. The probe TPA-Y can be applied to fluorescence imaging of reversible and dynamic interconversion between HSO 3 - and H 2 O 2 in living MCF-7 cells. [ABSTRACT FROM AUTHOR]

• Rose flower-like NiCo-LDH (RF-NiCo-LDH) is prepared derivating from NiCo-MOFs. • The 3D rough flower-like structure and synergy effect are beneficial to catalysis. • RF-NiCo-LDH shows high sensing performance for N 2 H 4 detection. • RF-NiCo-LDH operates efficiently in food samples (prawns, kelp, beer and soda). It is necessary to efficient detection hydrazine in food. Exploring highly sensitive, low-cost and fast response electrochemical hydrazine sensing methods has been a challenge in this field. In this paper, a conformal transformation method is used to prepare rose flower-like NiCo-LDH derivating from the bimetallic NiCo-MOFs, and the N 2 H 4 sensing platform with a large electrocatalytic area, high conductivity and good stability was constructed. Based on the synergy between Ni and Co and the remarkable catalytic activity of the rough 3D flower-like structure, the N 2 H 4 sensor has a linear response in the concentration range of 0.001–1 mmol/L and 1–7 mmol/L, with a sensitivity of 5342 μA L mmol−1 cm−2 and 2965 μA L mmol−1 cm−2 (S/N = 3), respectively, and low limit of detection of 0.043 μmol/L. This study opens a new door for the successful application of electrochemical sensors to detect N 2 H 4 in real food samples. [ABSTRACT FROM AUTHOR]

Mercury ion (Hg2+) is highly toxic to the environment and organisms, therefore, monitoring and quantitative detection of Hg2+ is of great significance. In this work, a new fluorescent probe TPEH that integrated tetraphenylethene (TPE) and 2-(2 ′ -hydroxyphenyl)benzothiazole was designed and synthesised. In EtOH/HEPES (2:8, v/v, pH = 7.2) solution, TPEH displays fluorescence turn on detection of Hg2+ with the advantages of swift response (<100 s), high selectivity and strong disturbance-resistant, a large Stokes shift (220 nm), and low limit of detection (81.7 nM). The sensing mechanism was proved to be Hg2+-triggered releasing of the aggregation-induced emission (AIE)-active precursor compound 2. TPEH has been successfully applied to detect Hg2+ in seafood and tea, and image Hg2+ in living cells. In addition, TPEH can be used to detect the content of Hg2+ in actual water samples with the aid of smartphone. [Display omitted] • A new AIE-based fluorescent probe TPEH for Hg2+ detection has been developed. • TPEH has the advantages of rapid response (<100 s), a large Stokes shift (220 nm), and a low detection limit (81.7 nM). • TPEH can detect Hg2+ in seafood and tea, and image Hg2+ in living cells. • TPEH can detect Hg2+ in actual water samples with the help of smartphone. [ABSTRACT FROM AUTHOR]

Abstract A simple and efficient functionalized graphene (f-graphene) doped chitosan (CS) based electrochemical aptasensor has been developed for ochratoxin A (OTA) detection. Use of f-graphene increased the electroactive surface area of the electrode and CS prevented leaching of the aptamer (APT) molecules. The dual properties of CS and f-graphene overall improved the sensor performance. The developed APT/SA/CS-f-graphene sensor has been characterized using Fourier Transform Infrared Spectroscopy (FTIR), Contact angle, Field emission - scanning electron microscopy (FE-SEM) and electrochemical studies. The aptasensor displayed OTA limit of detection (LOD) about 1 fg/mL for standard and 0.01 ng/mL for spiked sample within response time of 8 min. The reusable aptaelectrode retained 85% of initial current values after 7th reaction with stability of about 7 days. Besides, real application of the fabricated aptasensor has been evaluated in the grape juice samples. Recoveries of OTA in the range of 90–101% were estimated successfully. Highlights • Chitosan (CS) and graphene (f-graphene) has been used as suitable matrix for immobilization of aptamer (APT) • Biotinylated APT was immobilized onto streptavidine (SA) attached f-graphene via streptavidine-biotin coupling. • Detection limit of Ochratoxin A (OTA) is 1 fg/mL. Recoveries of OTA from the spiked grape juice ranged between 90-101%. • Reusability and shelf life was observed to be 7 times and 7 days, respectively. [ABSTRACT FROM AUTHOR]

Here, a solid/liquid phase extraction mode was used for the preconcentration of Pb(II) in water and food samples through a biomass reinforced graphene oxide (BGO) membrane. Taking advantage of the two modes, the synergistic effect of BGO membrane (solid extraction) and organic solvent (liquid extraction) enhances the extraction efficiency toward target ion. In detail, the effect of composition parameters in BGO membrane and experiment conditions such as pH, eluent types, elution time and sample volume were optimized, as well as shows no obvious interference toward different competing ions. Under the optimal experiment conditions, the limit of detection, precision as RSD% of this method were found to be 0.84 μg L −1 and 4.65%, respectively. Moreover, the large enrichment factor of BGO membrane demonstrates the applicability of the use of large sample volumes. Furthermore, the method was successfully verified by analyzing spiked Pb(II) in water and food samples. [ABSTRACT FROM AUTHOR]

Highlights • TiO 2 -Ag/PPy nanocomposite was synthesized. • A new modified electrochemical sensor based on TiO 2 -Ag/PPy nanocomposite was constructed and used for TA detection. • The sensor has low detection limit (2.0×10-8 mol L-1), high sensitivity, low interference and good stability. • Applied to different sample matrices. Abstract This study presents electrochemical determination of tyramine (TA) using a new electrochemical sensor (TiO 2 -Ag/PPy/GCE) based on TiO 2 -Ag/PPy nanocomposite modified glassy carbon electrode (GCE). In addition to SEM, AFM and XRD analysis, the presented sensor was studied with respect to its response to Fe(CN) 6 4−/3− and characterized by CV and EIS techniques. Under the optimum conditions, TiO 2 -Ag/PPy/GCE showed a good linear relationship over a concentration range from 4.10 × 10-8 to 3.06 × 10-6 M with a detection limit of 2 × 10-8 M. The availability of the sensor was examined by analysis of TA in food samples. [ABSTRACT FROM AUTHOR]

A stable chitosan protected tetrasulfonated copper phthalocyanine (Chit-TsCuPc) modified glassy carbon electrode (GCE) was used to aid the electrochemical detection of nitrite (NO 2 − ) in food samples. The electrochemical oxidation of NO 2 − was investigated on bare, chitosan and TsCuPc modified GCE in presence of phosphate buffer solution with an acidic medium. The elevated oxidation peak current was noticed at less oxidation potential for + 0.55 V vs. Ag/AgCl at Chit-TsCuPc modified electrode under the optimized experimental conditions. The plot displays the peak current against NO 2 − with a good linearity in the concentration rangefrom 6.5 × 10 −8  M to 5.0 × 10 −10 M. The linear regression equation is calculated to be I p (μA) = 0.5291 + 1.4894C (NO 2 − ), has a good correlation coefficient of 0.9949 and the detection limit of 22 nM (S/N = 3) with the current sensitivity of 4.964 μA nM −1  cm −2 . The standard addition method was adopted to measure the unknown NO 2 − concentration in food samples. [ABSTRACT FROM AUTHOR]

Abstract We isolated and characterized two novel rV5-like lytic bacteriophages from independently collected food samples. Nucleotide sequence analysis revealed that these phages have linear double-stranded DNA genomes comprising 138,073 bp with 213 CDS and 5 tRNA genes. The two genomes contain completely identical nucleotide sequence, albeit there is a 10,718 bp-long shift in the sequence. The GC content of the phage genomes was 43.7% and they showed high general homology to rV5-like phages. The new phages were termed C203 and P206. The genome of both phages contains a unique ORF that encodes for a putative phage homing endonuclease. The phage produced clear plaques with a burst size of approx. 1000 viral particles and a latent period of 60 min. Morphological investigation indicated that the new phages are members of the family Myoviridae with an approximate head length of 85 nm, tail length of 75 nm, and a head width of 96 nm. C203 and P206 exhibit a broad and uniform host range, which included enterohemorrhagic Escherichia coli strains of serogroup O157, multi drug resistant (MDR) E. coli strains of various sero- and pathotypes, and both Shigella sonnei and S. dysenteriae strains. C203 and P206 both effectively reduced the number of living EHEC O157:H7 Sakai in experimentally inoculated minced meat. The same broad host range, the lack of any virulence related genes, the stability and its short latent period suggest that these newly found phages could be suitable candidates as a bio-control agents against food-borne pathogenic Enterobacteria. Highlights • Whole genome sequence of two new rV5-like bacteriophages was determined. • The two phages have identical genome sequence except for a 10 kb sequence shift. • The two new phages establish a novel genotype among rV5-like phages. • The phages infect a wide range of pathogenic E. coli including O157:H7 strains. [ABSTRACT FROM AUTHOR]

Developing low-cost and efficient sensors for rapid, selective and sensitive detection of the transition metal ions in environmental and food science is very important. In this study, a novel dual-functional fluorescent “turn-on” sensor 3TP based on oligothiophene-phenylamine Schiff base has been synthesized for discrimination and simultaneous detection of both Al 3+ and Fe 3+ ions with high selectivity and anti-interference over other metal ions. Sensor 3TP displayed a very fast fluorescence-enhanced response towards Al 3+ and Fe 3+ ions with low detection limits (0.177 μM for Al 3+ and 0.172 μM for Fe 3+ ) and wide pH response range (4.0–12.0). The Al 3+ /Fe 3+ sensing mechanisms were investigated by fluorescence experiments, 1 H NMR titrations, FT-IR and ESI-MS spectra. Importantly, sensor 3TP was served as an efficient solid material for the highly sensitive and selective detection of Fe 3+ on TLC plates. Moreover, the sensor 3TP has been successfully used to detect trace Al 3+ and Fe 3+ in environment and food samples with satisfactory results and good recoveries, revealing a convenient, reliable and accurate method for Al 3+ and Fe 3+ analysis in real samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A highly active metal-free nanosheet based on B, N, S, P-doped carbon was prepared. • The BNSP-C has a specific surface area of 755.58 m2/g and a conductivity of 75.82 Ω. • It has a linear range of 0.1–130 μg/L for Cd(II) and 2–150 μg/L for Pb(II). • LODs of the sensor are as low as 0.10 μg/L for Cd(II) and 0.45 μg/L for Pb(II). • It can be used for direct analysis of heavy metals in fruits, vegetables and rice. Designing and synthesizing efficient and economical electro-sensing interface materials is essential for screening trace heavy metal ions in foods. In this study, we developed a multi-doped BNSP-C material with Zeolitic imidazolate framework-8 (ZIF-8) and non-metallic atoms (B, N, S, and P) for the simultaneous detection of the heavy metals Cd(II) and Pb(II) in complex food samples. The in situ doping of heteroatoms positively modifies the microstructure and current efficiency of the carbon precursor, creating additional active sites and defects, and imparting the material with improved electrical properties. The detection system optimized by square-wave anodic stripping voltammetry, was sensitive up to 1.290 and 0.661 μA·μM−1·cm−2. BNSP-C-Nafion/GCE has a high selectivity for target ions under the challenge of multiple coexisting ions and molecules. Furthermore, the current signals of Cd(II) and Pb(II) only dropped to 97.19 % and 98.98 % of the initial currents after a 30-day stability test. The strong catalytic activity and persistence of the BNSP-C-Nafion sensor were confirmed. This study explored the enhancement and detection of the ZIF-based electrochemical signals. In addition, we provided a convenient and green electrochemical technique for the simultaneous detection of Cd(II) and Pb(II). [ABSTRACT FROM AUTHOR]

Salmonella is a food-borne zoonotic pathogen that threatens food safety and public health security. Temperate phages can influence bacterial virulence and phenotype and play an important role in bacterial evolution. However, most studies on Salmonella temperate phages focus on prophage induced by bacteria, with few reports on Salmonella temperate phages isolated in the environment. Moreover, whether temperate phages drive bacterial virulence and biofilm formation in food and animal models remains unknown. In this study, Salmonella temperate phage vB_Sal_PHB48 was isolated from sewage. TEM and phylogenetic analysis indicated that phage PHB48 belongs to the Myoviridae family. Additionally, Salmonella Typhimurium integrating PHB48 was screened and designated as Sal013+. Whole genome sequencing revealed that the integration site was specific and we confirmed that the integration of PHB48 did not change the O-antigen and coding sequences of Sal013. Our in vitro and in vivo studies showed that the integration of PHB48 could significantly enhance the virulence and biofilm formation of S. Typhimurium. More importantly, the integration of PHB48 significantly improved the colonization and contamination ability of bacteria in food samples. In conclusion, we isolated Salmonella temperate phage directly from the environment and systematically clarified that PHB48 enhanced the virulence and biofilm-forming ability of Salmonella. In addition, we found that PHB48 increased the colonization and contamination ability of Salmonella in food samples. These results indicated that the highly pathogenic Salmonella induced by temperate phage was more harmful to food matrices and public health security. Our results could enhance the understanding of the evolutionary relationship between bacteriophages and bacteria, and raise public awareness of large-scale outbreaks resulting from Salmonella virulence enhancement in food industry. • Salmonella temperate phage vB_Sal_PHB48 was directly isolated from the sewage. • We screened S. Typhimurium integrated PHB48 and determined the integration site. • Integration of PHB48 enhanced virulence and biofilm-forming ability of Sal013+. • PHB48 enhanced the colonization and contamination ability of Sal013+ on food. [ABSTRACT FROM AUTHOR]

[Display omitted] • A nickel complex (NiC) sensor with thiourea binding sites was developed for colorimetric sensing. • The detection limits of NiC toward CN− and S2– reached 3.54 × 10−8 and 2.87 × 10−8 M. • The interaction between NiC and analytes (CN– or S2–) results from deprotonation. • The colorimetric response is due to the intramolecular charge transfer mechanism. • NiC sensor was applied to detect CN− in the food samples. Since cyanide is highly toxic that can lead to respiratory arrest and death, it is important to develop practical diagnostic methods for the sensing of cyanide. In this study, the colorimetric sensing of cyanide was achieved by a nickel complex (NiC) sensor with thiourea binding sites. NiC was prepared and characterized by 1H NMR, single-crystal X-ray crystallography, FTIR, and Mass spectra. When the cyanide and sulfide ions were added to NiC sensor, the color changed from light yellow to canary yellow and pale yellow to golden yellow, respectively. NMR titration results confirmed that the colorimetric response toward cyanide resulted from the deprotonation and formation of a guest–host complex. A binding mechanism is proposed based on the mass spectra, 1H NMR titration, and stoichiometry studies. The binding constant and detection limit of the NiC sensor toward cyanide was also investigated. The detection limits of NiC toward cyanide and sulfide reached 35.4 nM and 28.7 nM, respectively, lower than the World Health Organization (WHO)-allowed cyanide concentration in drinking water. The NiC complex possesses high selectivity to cyanide and sulfide through deprotonation of the –NH- protons. The detection of trace amounts of cyanide ions in natural food samples, such as cassava flour and sprouting potatoes, was also achieved by the NiC sensor. [ABSTRACT FROM AUTHOR]

Novel hollow mesoporous molecularly imprinted polymers (HM-MIPs) were proposed for highly selective and sensitive detection of estrogens in food samples. HM-MIPs were prepared by one-pot surface imprinting method using17β-estradiol (E2) as template followed by chemical selective etching to remove solid silica core. Transmission electron microscopy coupled with N 2 adsorption experiment confirmed the successful formation of hollow mesoporous structure. Binding adsorption experiment indicated that HM-MIPs have high binding capacity and fast mass transfer property, and class selective recognition of estrogens is possible by E2 imprinted HM-MIPs. HM-MIPs-SPE-HPLC was employed to enrich and detect E1, E2 and E3 in cucumber, milk powder and grass carp samples. Satisfactory recoveries in the range of 85.6%–101.2% and relative standard deviation lower than 4.3% were obtained. The limits of detection for these estrogens were in the range of 33–22 ng L −1 . Thus, HM-MIPs-SPE method proved to be an accuracy and practical platform for detection of estrogens in food samples. [ABSTRACT FROM AUTHOR]

A bamboo fiber mini-column impregnated with bathocuproine is proposed as an off-line pre-concentration system for determination of copper speciation in food samples using flame atomic absorption spectrometry (FAAS). Sampling flow rate, elution flow rate, pH and buffer concentration were evaluated for their importance in the solid-phase extraction using a 2 4 full factorial design and were all found to be significant. Afterward, a Doehlert matrix was used to optimize the pre-concentration process. The experimental conditions established with this design were: 8.0 mL min − 1 sampling flow rate, 10.0 mL min − 1 elution flow rate and 0.02 mol L − 1 buffer at pH 5.5. This system allowed the determination of copper with a limit of detection (LOD) of 0.5 μg L − 1 , a limit of quantification (LOQ) of 1.66 μg L − 1 and a precision expressed as relative standard deviation (RSD) of 2.70 and 2.79% for copper concentrations of 5.0 and 20 μg L − 1 , respectively. A pre-concentration factor of 33 was achieved using a 50.0-mL sample volume. The accuracy was confirmed by analysis of a certified reference material (NIST SRM 1573a Tomato Leaves). Spike/recovery tests were performed with results ranging from 93 to 100%. The developed method was applied to determine copper in corn flour, cassava root flour, oregano leaves and cumin. In addition, a speciation strategy was used for wine samples, in which free copper was evaluated in 40.00-mL aliquots of undigested samples and total copper assessed in samples digested before the pre-concentration step. [ABSTRACT FROM AUTHOR]

A bioinspired Au@Ag nanodome-cones array (Au@Ag NDCA) surface-enhanced Raman scattering (SERS) chip was developed for efficient residue analyses of food samples. The cicada wing inspired Au@Ag NDCA chip was fabricated by a bottom-up method, Au nanocones array was firstly grown onto nickel foil by displacement reaction and cetyltrimethylammonium bromide guidance growth, and then silver shell with controllable thickness was coated onto the Au nanocones array by magnetron sputtering. The Au@Ag NDCA chip exhibited good SERS performances with high enhancement factor of 1.2 × 108, good uniformity with relative standard deviation (RSD) less than 7.5% (n = 25), good inter-batch reproducibility with RSD less than 9.4% (n = 9), and long-term stability over 9 weeks. By adapting a minimized sample preparation, Au@Ag NDCA chip combined with a 96-well plate could realize high-throughput SERS analyses of 96 samples with average analysis time less than 10 min. The substrate was applied for quantitative analyses of two food projects. One was 6-benzylaminopurine auxin residue in sprout samples with detection limit of 38.8 μg/L, recoveries of 93.3–105.4% and RSDs of 1.5–6.5%, and the other was an edible spice of 4-amino-5,6-dimethylthieno (2,3-d) pyrimidin-2(1H)-one hydrochloride additive in beverage samples with detection limit of 18.0 μg/L, recoveries of 96.2–106.6% and RSDs of 3.5–7.9%. All the SERS results were well confirmed by conventional high-performance liquid chromatographic methods with relative errors less than 9.7%. The robust Au@Ag NDCA chip exhibited good analytical performances possessed great potential for convenient and reliable analyses of food quality and safety. [Display omitted] • Au@Ag nanodome-cones array chip was prepared by cicada-wing inspiration. • The enhancement factors of crystal violet, 6-benzylaminopurine, and 4-amino-5,6-dimethylthieno (2,3-d) pyrimidin-2(1H)-one hydrochloride were 1.2 × 108, 2.4 × 106, and 3.5 × 105, respectively. • The interfacial adsorption principle was elaborated for target capture. • An economical and arrayed SERS method was established for food safety/quality analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Difunctional probe for colorimetric and NIR emission sensing SO 2 /H 2 O 2 is synthesized. • Reversible response is realized by SO 2 involved addition and H 2 O 2 induced elimination. • The fluorescence change caused by HSO 3 - is blocking ICT and occurring PET process. • Probe can detect SO 2 in living cells and food samples including sugar, biscuit, wine. Preservative sulfur dioxide (SO 2) and bleach hydrogen peroxide (H 2 O 2) were widely used in the food industry, at the same time, they were also a redox pair in biological systems. Therefore, the reversible sensing SO 2 /H 2 O 2 was of great significance in food safety and biology. In this paper, a colorimetric and NIR fluorescent dual channels response probe (DCA-Bba) for SO 2 /H 2 O 2 based on chromene-barbiturate was developed. DCA-Bba exhibited a rapid and sensitive recognition of SO 2 , and the adduct DCA-Bba -HSO 3 − could detect H 2 O 2 in PBS (with 10 % DMSO, v/v, pH 7.4) solution. The reversible response of DCA-Bba was implemented by HSO 3 − involved 1,4-addition and H 2 O 2 induced elimination reaction. DCA-Bba showed a strong red fluorescence based on the intramolecular charge transfer (ICT) process, after the recognition of SO 2 , the fluorescence of the adduct was quenched based on the photoinduced electron transfer (PET) process. And importantly, DCA-Bba had been applied for imaging SO 2 /H 2 O 2 redox cycles in living cells, as well as could detect the levels of SO 2 in white sugar, biscuit, Chinese liquor and red wine samples. [ABSTRACT FROM AUTHOR]

• NiAl-LDH/α-Fe 2 O 3 photoelectrochemical sensor has been successfully fabricated. • NiAl-LDH/α-Fe 2 O 3 exhibits excellent photoelectrochemical sensing toward glucose. • NiAl-LDH acts as and/or provide active sites for glucose detection. • NiAl-LDH enlarges the band bending and decreases the charge transfer resistance. Hematite (α-Fe 2 O 3) is a promising photoelectrode material for photoelectrochemical (PEC) sensors. However, it still suffers from serious surface charge recombination and slow interfacial charge transfer kinetics. In this work, NiAl-layered double hydroxides decorated on α-Fe 2 O 3 (NiAl-LDH/α-Fe 2 O 3) was successfully fabricated via a facile hydrothermal method. The NiAl-LDH/α-Fe 2 O 3 exhibits excellent PEC response toward glucose, with a good linear range from 0.01 to 2 mM, a high sensitivity of 274.7 μA·mM−1·cm−2 and a low detection limit of 0.005 mM. NiAl-LDH/α-Fe 2 O 3 PEC sensor could be used for glucose determination in various food samples, such as bread, toast and glucose oral solution, which achieved comparable results with that of HPLC. PEC and electrochemical characterizations indicate NiAl-LDH could act as and/or provide active sites for glucose detection, enlarge the band bending and decrease the charge transfer resistance, thus significantly improve the PEC response of α-Fe 2 O 3 toward glucose. [ABSTRACT FROM AUTHOR]

• Three Benzyl-functionalized MIL with novel structure were successfully fabricated. • MIL has the multi-function of extraction, visual observation and magnetic separation. • The functionalized MIL showed excellent extraction ability for FQs in milk and honey. • MIL-DLLME is a simple, rapid, efficient and sensitive method for trace FQs monitor. • The LOD, recovery and RSD were 0.47–0.56 μg/L, 90.8 %–107.8 %, and 5.4 % respectively. The novel hydrophobic cobalt anion-based benzyl-functionalized magnetic ionic liquid (MIL) was first designed, synthesized, and employed as a multifunctional extractant (for extraction, visual observation, and magnetic separation) for fast dispersive liquid–liquid microextraction of fluoroquinolones (FQs). According to the aromatic structure of FQs, three benzyl-functionalized MILs were customized by introducing various aromatic functional groups (benzyl, paracetyl phenyl, and m -methoxyphenyl) to justify the extraction efficiency and selectivity. In particular, the paracetyl phenyl functionalized MIL showed superior extraction efficiency among others due to its hydrophobicity and strong interactions of hydrogen bonding and π-π stacking. Moreover, under optimal conditions, the limits of detection were as low as 0.47–0.56 μg/L, and the enhancement factors were as high as 88–95. The recoveries were between 90.8 % and 107.8 %, and the relative standard deviation was less than 5.4 %. Ascribed to these outstanding experimental results, the benzyl-functionalized MIL is a potential magnetic extractant for detecting trace FQs in food samples. [ABSTRACT FROM AUTHOR]

We developed a fully integrated smart sensing device for on-site testing of food to detect trace formaldehyde (FA). A nano-palladium grafted laser-induced graphene (nanoPd@LIG) composite was synthesized by one-step laser irradiation of a Pd2+-chitosan-polyimide precursor. The composite was synthesized in the form of a three-electrode sensor on a polymer substrate. The electrochemical properties and morphology of the fabricated composite were characterized and the electrochemical kinetics of FA oxidation at the nanoPd@LIG electrode were investigated. The nanoPd@LIG electrode was combined with a smart electrochemical sensing (SES) device to determine FA electrochemically. The proposed SES device uses near field communication (NFC) to receive power and transfer data between a smartphone interface and a battery-free sensor. The proposed FA sensor exhibited a linear detection range from 0.01 to 4.0 mM, a limit of detection of 6.4 μM, good reproducibility (RSDs between 2.0 and 10.1%) and good anti-interference properties for FA detection. The proposed system was used to detect FA in real food samples and the results correlated well with the results from a commercial potentiostat and a spectrophotometric analysis. [Display omitted] • A porous graphene structure was produced by laser scribing. • The porous graphene was simultaneously decorated with Pd nanoparticles. • The composite was used as an electrode in a portable formaldehyde sensing system. • The portable system uses near field communication to enable on-site testing. [ABSTRACT FROM AUTHOR]

A simple fluorescent probe (TPE-1) based on the combination of tetraphenylethene (TPE) and 2-(2′-hydroxyphenyl)benzothiazole (HBT) was synthesized. TPE-1 possesses both aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) characteristics. The TPE-1 aggregates exhibited rapid (10 s) and highly selective recognition of Cu2+ in THF/H 2 O (1:9, v/v, HEPES 20 mM, pH = 7.4) solution, and was induced an "on-off" change in the fluorescence. TPE-1-Cu 2+ complexes generated in situ can also be used as sensing ensembles for highly selective detection of H 2 S by Cu2+ displacement. As a result, the fluorescence of TPE-1 was recovered again, and an "on-off-on" fluorescence variation was used to relay Cu2+ and H 2 S recognition. The detection limits of the probes for Cu2+ and H 2 S are 9.91 × 10−8 M and 3.80 × 10−7 M, respectively. In addition, the probes can be applied to detect Cu2+ and H 2 S in some food samples and can also be applied to cell imaging experiments. Relay recognition of Cu2+ and H 2 S by a fluorescent probe regulated by AIE and its application in food and cell imaging. [Display omitted] • An AIE-based fluorescent probe TPE-1 was designed and synthesized. • TPE-1 can relay identify Cu2+ and H 2 S with high sensitivity, high selectivity, large Stokes shift, and low detection limit. • TPE-1 can rapidly relay responses to Cu2+ and H 2 S with on-off-on fluorescence changes. • TPE-1 is suitable to assay the Cu2+ and H 2 S level in water, seafood, tea and red wine samples. [ABSTRACT FROM AUTHOR]

Here in we report preparation of MnFe 2 O 4 and magnetic takovite–aluminosilicate adsorbent via precipitation methodology. The synthesized nanocomposite was applied in preconcentration of Pb 2+ ions from various matrices. The structural, surface, and magnetic characteristics of the adsorbent were investigated by XRD, EDX, FE-SEM, and VSM techniques. Several parameters affecting preconcentration efficiency, including sample pH, contact time, adsorbent amount, and sample volume were studied and optimized. Under optimized conditions, the calibration graph was linear in the range of 2.0–100 μg L −1 , the relative standard deviation was 3.00% (n = 5), the limit of detection was 0.67 μg L −1 , and the enrichment factor was 70.0. The maximum adsorption capacity of the adsorbent was calculated to be 69.9 mg g −1 . The suggested method was successfully applied in determination of trace amount of Pb 2+ ions in water and food samples. [ABSTRACT FROM AUTHOR]

Mycotoxins are the most common feed and food contaminants affecting animals and humans, respectively; continuous exposure causes tremendous health problems such as kidney disorders, infertility, immune suppression, liver inflammation, and cancer. Consequently, their control and quantification in food materials is crucial. Biosensors are potential tools for the rapid detection and quantification of mycotoxins with high sensitivity and selectivity. Nanoliposomes (NLs) are vesicular carriers formed by self-assembling phospholipids that surround the aqueous cores. Utilizing their biocompatibility, biodegradability, and high carrying capacity, researchers have employed NLs in biosensors for monitoring various targets in biological and food samples. The NLs are used for surface modification, signal marker delivery, and detection of toxins, bacteria, pesticides, and diseases. Here, we review marker-entrapped NLs used in the development of NL-based biosensors for mycotoxins. These biosensors are sensitive, selective, portable, and cost-effective analytical tools, and the resulting signal can be produced and/or amplified with or without destroying the NLs. In addition, this review emphasizes the benefits of the immunoliposome method in comparison with traditional detection approaches. We expect this review to serve as a valuable reference for researchers in this rapidly growing field. The insights provided may facilitate the rational design of next-generation NL-based biosensors. • Biosensors based on NLs for food mycotoxins detection. • Review focuses on comprehensive research relating to the development of NLs-sensors. • Immunoassay approaches emphasize current advances, challenges, and trends. • NLs-sensors exhibit outstanding inclusive and multiplex analytical efficacy. • NLs-sensor methods measures mycotoxins in law and regulations. [ABSTRACT FROM AUTHOR]

In recent years, microwave-assisted extraction (MAE) has attracted growing interest, as it is an effective method for the rapid extraction of a number of trace organic pollutants from food and environmental samples, due to advantages in facilitating on-line measurements, high efficiency, and significantly lower extraction time and solvent consumption than classical techniques. This review describes recent advances of MAE from the perspective of green analytical chemistry, and summarizes the main results in applications published in the period 2008–14. Finally, we compare the performance of this technique to that of traditional extraction and other recent techniques. [ABSTRACT FROM AUTHOR]