Iron nanoparticles (FeNPs) speak to promising specialists for ecological remediation. We synthesized iron nanoparticles by using Terminalia bellirica (TB) fruit extract to degrade malachite green (MG), an organic dye. We observed the surface plasmon resonance (SPR) with a UV–visible spectrophotometer and found FeNPs to be nonplasmonic. The Terminalia bellirica fruit extract includes -OH groups in the nanoparticle synthesis response, as demonstrated by FTIR spectroscopy. We used high-resolution transmission electron microscopy (HRTEM) to confirm the spherical shape of iron nanoparticles, measuring approximately 25–60 nm. XRD results give an amorphous nature (α-Fe) to nanoparticles. An increase in temperature led to the growth of Fe2O3 NPs in the synthesized FeNPs. Zeta potential was used to characterize the soundness of synthesized FeNPs. It breaks down the most at a pH of 6.0 and a temperature of 80 °C, with Fe3+ and TB fruit extract adding up to 92

Heavy metal contamination in water is a major global issue today due to its toxicity and carcinogenicity. Pollutant removal from wastewater is crucial to ensure the quality of available water resources (including natural water bodies or reclaimed waters). Diverse techniques have been developed to deal with water quality concerns. Carbon-based nanomaterials have recently sparked significant interest due to their high surface area, ease of functionalization, ease of biodegradation, high aspect ratio, and pore structure, which are adsorption capacity cables and have drawn a special focus in environmental applications, particularly wastewater treatment. More consideration should be given to the water purification selectivity in long-term operation at conditions like those in the field for performance study to broaden the uses of graphene-based materials. Graphene materials' capacity to absorb water pollutants has received most of the attention in literature studies; however, there are very little recent data on its sieving capabilities. A comprehensive understanding of graphene is crucial to realize graphene materials' promise fully. Future study is anticipated to examine interest in creating hybrid graphene materials. The present book chapter explains the impact of carbon-based nanomaterials on wastewater treatment.

Heavy metal contamination is a standout among the most genuine ecological issues: toxicity, persistence, bioaccumulation, and biomagnification through food chains. The present work aims at the synthesis of abundant, fast-sensing electrochemical sensors MoS2 and MoS2@rGO composite by the hydrothermal method to develop electrochemical sensors for the detection of Mercury (Hg-II). The synthesized material was characterized and conformed to a hierarchical spherical sponge-like structure with a high surface-tovolume ratio. The electrochemical sensor conditions were observed at ambient conditions to detect Hg (II) (0.5, 1, 1.5, 2, 2.5, 3, 3.5 mu m L-1 was used) and the results showed very promisingly. The limit of detection (LOD) was found to be 2.0 x 10(-7) mu g/mL for MoS2, 1.22 x 10(-8 )mu g/mL for composite. The heavy metals were spiked in green tea extract to observe the sensor ability of the material. The sensor ability for the material for real-time detection of green tea was found to be LOD-2.12 x 10(-7) mu g/mL (MoS2) and 1.21 x 10(-9) mu g/mL (MoS2@rGO). Copyright (C)2022 Elsevier Ltd. All rights reserved.

Norfloxacin is an antibiotic in the fluoroquinolone family licenced for use in animals. However, residues in animal products can have negative consequences for consumers. As a result, residue detection in various food matrices must be considered. Norfloxacin accumulates in animal-derived foods, causing deleterious consequences in humans such as foetal deformity, renal failure and drug resistance. A built-in SERS-Au@Ag nanosensor coupled with GA-PLS was used to rapidly detect norfloxacin in the specimen of the spiked fish muscles due to the threat to human lives. A detection limit of 2.36 × 10−5 μg/mL was realized in the spiked fish muscle sample for norfloxacin compared to the European Commission’s maximum threshold level of 100 μg/kg, indicating the sensor’s ability to detect and quantify norfloxacin at a relatively lower level. The recovery rates (RC) and coefficient of variation (CV) measured in the spiked fish muscle samples for norfloxacin analytes and their standard solutions were between 99.70–105.00% and 0.17–5.21%, respectively. The low CV values imply the reproducibility of the obtained data. The constructed model recorded residual predictive deviations (RPD) greater than three (3), demonstrating the robustness and resilience of the developed genetic algorithm-partial least squares (GA-PLS) model. GA-PLS-built models predicted all results within 4.07 s, which indicates the nanosensor’s ability to rapidly detect norfloxacin in fish to guarantee safety and public health. The SERS probe holds promise for rapid quantification of norfloxacin at microgram per milliliter level in fish to guarantee safety in commerce.

Ochratoxin-A (OTA) and aflatoxin-B1 (AFT-B1) pose debilitating health threats to consumers and therefore require rapid monitoring with sensors. This work synthesized silver nanoparticles (AgNPs) within (4 <= pH <= 11) +/- 0.2 to attain different enhancement-factors (EF). AgNP@pH-11 which gave the highest SERS-EF (1.45 x 10(8)) was selected to fabricate SERS-sensor; and coupled to two chemometric algorithms for the prediction of OTA and AFT-B1 in prepared standard solutions (SS) and spiked-cocoa-beans samples (SCBS). The LOD for OTA (2.63 pg/mL) and AFT-B1 (4.15 pg/mL) in the SCBS were lower compared with 0.002 mu g/mL. The built-models recorded residual-predictive-deviations above 3. Obtained recovery rates of 96-110%; and the low coefficients of variation (2.12-8.07%) realized for both toxins suggest the predicted results are reproducible. The SERS-sensor holds promise for the rapid quantification of OTA and AFT-B1 at pg/mL level in cocoa beans to enable safety assurance in the cocoa beans industry.

Black tea like other food crops is prone to mercury ion (Hg2+) contamination right from cultivation to industrial processing. Due to the dangerous health effects posed even in trace contents, sensitive detection and quantification sensors are required. This study employed the surface-enhanced Raman scattering (SERS) enhancement property of 4-aminothiophenol (4-ATP) as a signal turn off approach functionalized on Ag-Au alloyed nanopartide to firstly detect Hg2+ in standard solutions and spiked tea samples. Different chemometric algorithms were applied on the acquired SERS and inductively coupled plasma-mass spectrometry (ICP-MS) chemical reference data to select effective wavelengths and spectral variables in order to develop models to predict the Hg2+. Results indicated that Ag-Au/4-ATP SERS sensor combined with ant colony optimization partial least squares (ACO-PLS) exhibited the best correlation efficient and minimum errors for Hg2+ standard solutions (R-c = 0.984, R-p = 0.974, RMSEC = 0.157 mu g/mL, RMSEP = 0.211 mu g/mL) and spiked tea samples (R-c = 0.979, R-p = 0.963, RMSEC = 0.181 mu g/g and RMSEP = 0210 mu g/g). The limit of detection of the proposed sensor was 4.12 x 10(-7) mu g/mL for Hg2+ standard solutions and 2.83 x 10(-5) mu g/g for Hg2+ spiked tea samples. High stability and reproducibility with relative standard deviation of 1.14% and 0.84% were detected. The potent strong relationship between the SERS sensor and the chemical reference method encourages the application of the developed chemometrics coupled SERS system for future monitoring and evaluation of Hg2+ in tea. (C) 2020 Elsevier B.V. All rights reserved.

In the present investigation, a detailed spectroscopic analysis on the interaction mechanism of 1-Butyl-2,3-dimethylimidazolium tetrafluoroborate [Bdmim][BF4] with human serum albumin (HSA) and bovine serum albumin (BSA) has been carried out by multispectroscopic studies. The results obtained from the fluorescence titration experiments indicated the existence of a weak interaction between HSA/BSA and [Bdmim][BF4]. The binding parameters revealed that [Bdmim][BF4] binds to HSA by cooperative process, while in the case of BSA the binding of [Bdmim][BF4] is found to be independent to the binding sites having the similar affinity. The outcome of the CD and absorbance spectral experiments of HSA/BSA-[Bdmim][BF4] systems revealed the occurrence of very little modifications in the micro-environmental and secondary structural conformations of HSA/BSA. Autodocking and molecular dynamics simulation studies indicated that the positively charged imidazolium moieties of ionic liquid (IL) is located in the vicinity of subdomain IIA and subdomain IB in HSA and BSA, respectively. The enzyme-like activity of HSA/BSA is inhibited slightly upon complexation with [Bdmim][BF4].

Noble bimetallic and trimetallic nanoparticles (NBT-NPs) have superior biomedical applications as compared to their monometallic counterparts. The performance of these nanomaterials depends on their composition, shape and size. Hence, the controlled-synthesis of these nanomaterials is a hot area of research. Till date, no review article in the literature accounts regarding the controlled-synthesis and biomedical applications related to morphology, optimum composition, biocompatibility and versatile chemistry of NBT-NPs. Taking this into contemplation, an effort was made to provide a clear insight into the morphology-controlled synthesis and size/shape-dependent anticancer and bactericidal applications of NBT-NPs. Chemical reduction method for the controlled-synthesis of NBT-NPs is reviewed critically. Furthermore, the potential role of various reaction parameters such as time, reducing agents, stabilizing/capping agents, nature/concentration of precursors, temperature and pH in the shape/size-controlled synthesis of these nanomaterials are discussed. In the second part of this article, anticancer and bactericidal applications of the NBT-NPs are reviewed and the influences of optimum composition, size, surface structure, versatile chemistry and synergism are studied. Finally, the current challenges in the controlled-synthesis and biomedical applications of these nanomaterials, and prospects to resolve related issues are discussed. HighlightsChemical reduction method for the synthesis of NBT-NPs is reviewed.The influences of parameters on the control synthesis of NBT-NPs are discussed.Antibacterial and anticancer applications and cytotoxicity of NBT-NPs are reviewed.Possible solutions for the key challenges are discussed.Outlooks about the synthesis and biomedical applications of NBT-NPs are discussed.

A technique for predicting the K-value of fish freshness using Fourier Transform-Near-Infrared (FT-NIR) coupled with chemometric algorithms was developed. FT-NIR spectra of 150 fresh fish were acquired, and their respective K-value estimated using HPLC procedures. Acquired spectra were pretreated using standard normal variate (SNV) to eliminate extraneous information. The developed FT-NIR coupled chemometric algorithm attained K-values of the correlation coefficient between 0.9471-0.9786 and the predictive deviation of the residuals (RPD) of 3.53-4.19. The performance of the ant colony partial least squares (ACO-PLS) compared to the other chemometric algorithms proved superior for the estimation of K-values of fish freshness with a correlation coefficient of 98.27 % for the training set and 97.86 % for the test set recorded. This implies that FT-NIR, coupled with different chemometric algorithms, has the potential to be deployed for accurate prediction of K-value as a freshness indicator.

In the present study, the multifunctional applications of food waste derived carbon quantum dots (CQD) have been demonstrated. The results obtained from the absorption and fluorescence spectroscopic analysis affirmed the superior photophysical property of the prepared CQD. X-ray diffraction (XRD), Fourier transformed infra-red spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) studies further confirmed the crystallographic phase and surface functional groups present in the CQD. The ultrafine size of the CQD is established from the high-resolution transmission electron microscope (HR-TEM) micrographs with the grain size of 2 - 4 nm. The excellent fluorescence property of the CQD is utilised to detect trace levels of Au3+ ions by simply mixing aqueous dispersion of CQD with ascorbic acid (AA). The sensing mechanism is based on the reduction of Au3+ to gold nanoparticles (AuNPs) by AA and the subsequent AuNPs induced fluorescence quenching of CQD by synergistic static quenching and inner filter effect. The CQD/AA probe could selectively detect Au3+ ion as low as 0.95 mu M. The cytotoxicity of the CQD toward U-251 MG glioblastoma cell revealed that the CQD did not possess any significant cytotoxicity. The application of CQD in bioimaging of cells is ascertained by fluorescence microscopic analysis. Furthermore, fluorescent polymer films were prepared by incorporating CQD within the polymer matrix (poly-vinyl-alcohol).

The current study explores the first full mode liquid microextraction technique coupled with surface-enhanced Raman spectroscopy (SERS), and has been successfully applied for chromium speciation in food and environmental matrices. Herein, chromium as chlorochromate anion [CrO3Cl](-) and the cationic rhodamine 6G [RG](+) dye has been extracted in organic phase as a complex ion associate [RG+.CrO3Cl-.nS](org) at pH = 1.0. Afterwards, the extracted phase was deposited on the surface of the nano-flower shaped silver nanoparticles substrate and the SERS response was monitored against the reagent blank at 1505 cm(-1). Substrate characterizations, reaction mechanism assignment, stoichiometry, speciation, analytical applications, selectivity and validation were performed. The analytical procedure exhibits a detection limit of 0.03 mu g L-1 under the optimized experimental conditions. The accuracy of the proposed strategy was validated by inductively coupled plasma optical emission spectrometry method using student's t-and F tests at 95% confidence.

Trace detection of toxic chemicals in foodstuffs is of great concern in recent years. Surface-enhanced Raman scattering (SERS) has drawn significant attention in the monitoring of food safety due to its high sensitivity. This study synthesized signal optimized flower-like silver nanoparticle-(AgNP) with EF at 25 degrees C of 1.39 x 10(6) to extend the SERS application for pesticide sensing in foodstuffs. The synthesized AgNP was deployed as SERS based sensing platform to detect methomyl, acetamiprid-(AC) and 2,4-dichlorophenoxyacetic acid-(2,4-D) residue levels in green tea via solid-phase extraction. A linear correlation was twigged between the SERS signal and the concentration for methomyl, AC and 2,4-D with regression coefficient of 0.9974, 0.9956 and 0.9982 and limit of detection of 5.58 x10(-4), 1.88 x10(-4) and 4.72 x10(-3) mu g/mL, respectively; the RSD value < 5% was recorded for accuracy and precision analysis suggesting that proposed method could be deployed for the monitoring of methomyl, AC and 2,4-D residue levels in green tea.

The current study assembles liquid-microextraction, surface enhanced Raman scattering (SERS) and chemometrics algorithms in one platform for chromium speciation using octahedral Cu2O@Ag nanocomposites (Cu2O@AgNCs) as a SERS substrate.

AgNPs-plated-ZnO nanoflower (NFs)-like structures (Ag@ZnO NFs) with optimised signals were synthesised via wet chemical method at different temperatures (50-80 degrees C). The enhancement factors (EFs) computed for the resultant Ag@ZnO ranged between 2.36-8.46x10(7) obtained at the different temperatures using 4-aminothiophenol (4-ATP). The achieved EF results indicate Ag@ZnO synthesised at 50 degrees C gave the best enhancement. It was therefore selected, characterised and used to fabricate a SERS-based nanosensor for the detection of 2,4-dichlorophenoxyacetic acid (2,4-D) with a limit of detection (LOD) of 2.87 x 10(-3) mu g/L. realised. (C) 2019 Elsevier B.V. All rights reserved.

Black tea composite contains a wide range of simple and complex phenolic compounds known for their antioxidant capabilities. Herein, a portable near-infrared (NIR) spectroscopy (899-1724nm) was used to predict the concentrations of cianidanol, ferulic acid, gallic acid, L-epicatechin, phloridzin and rutin in congou black tea. High-performance liquid chromatography-diode array detector (HPLC-DAD) was also utilized as a reference method. Models were predicted and constructed based on the data acquisition from portable NIR and HPLC-DAD using partial least squares (PLS) followed by variables selection algorithms such as competitive adaptive reweighted sampling-PLS and ant colony optimization-PLS. The correlation coefficient of calibration (R-C) and correlation coefficient of prediction (Rp) was found in ranged from 0.785 to 0.979 and 0.751 to 0.969, respectively. The overall results indicates portable NIR combined successfully with multivariate chemometrics offers a non-destructive technique for the rapid screening of the phenolic compounds of congou black tea. Practical applicationsPhenolic compounds play a significant role or as a key indicator of black tea quality. To the best of our knowledge, this is the first study for monitoring these compounds during black tea fermentation. Current study reported a first time non-invasive and non-destructive method for determining the quality index of black tea with reasonable accuracy and that could be endorsed a model approach as it addresses more advantages over conventional methods. This study successfully predicted phenolic compounds in black tea during fermentation after using a portable near-infrared spectroscopy coupled multivariate chemometrics. Furthermore, current work encourages fast, nondestructive quantification of various analyte in food and biological engineering as a quality and safety indicator.

This study focused on the fabrication of a rapid, highly sensitive and inexpensive technique for the quantification of imidacloprid residue in green tea, based on surface-enhanced Raman scattering (SERS) using highly roughned surface flower shaped silver nanostructure (as SERS substrate) coupled with the chemometrics algorithm. The basic principle of this method is imidacloprid yielded SERS signal after adsorption on Ag-NF under laser excitation by the electromagnetic enhancement and the intensity of the peak is proportional to the concentration ranging from 1.0 x 10(3) to 1.0 x 10(-4) mu g/mL. Among the models used, the GA-PLS (Genetic algorithm-partial least square) exhibited superiority to quantify imidacloprid residue in green tea. The model achieved Rp (correlation coefficient) of 0.9702 with RPD of 4.95% in the test set and RSD for precision recorded up to 4.50%. Therefore, the proposed sensor could be employed to quantify imidacloprid residue in green tea for the safeguarding of quality and human health. (C) 2018 Elsevier B.V. All rights reserved.

This paper focused on the quick and nondestructive evaluation of trimethylamine (TMA-N) in fish storage which is sequent to its freshness, the key for controlling the quality and safety of fish products by combining Fourier transform near-infrared (FT-NIR) and chemometric techniques. Calibration models of fish freshness were established using three multivariate chemometric methods—partial least square (PLS), synergy interval PLS (Si-PLS), and genetic algorithm PLS (GA-PLS) for quantitative prediction of TMA-N in fish. Results of the developed model were estimated using the correlation coefficients of the prediction (Rp) and calibration (Rc); root mean square error of prediction (RMSEP) and the ratio of sample standard deviation to RMSEP (RPD). The established model’s performance achieved 0.943 ≤ Rp ≤ 0.977 and 4.25 ≤ RPD ≤ 4.30. The model’s prediction strength improved in the order PLS < Si-PLS < GA-PLS. GA-PLS significantly improved the prediction of TMA-N prediction with RMSEC = 5.08 and Rc = 98.28 for the calibration data whereas the prediction set gave an RMSEP = 5.10 and Rp = 97.70. FT-NIR spectroscopy combined with GA-PLS technique may be employed for rapid and non-invasive quantification of TMA-N in fish for monitoring safety and quality.