Rapid and simultaneous determination of mixed pesticide residues in apple using SERS coupled with multivariate analysis.

This study aims to apply multivariate analysis algorithms for modeling the same spectra, for simultaneous determination of pymetrozine and carbendazim residues in apple. To mitigate the impact of competitive adsorption, SERS spectra are obtained from mixed solutions of pymetrozine and carbendazim at varying concentration ratios, which are then utilized for modeling. Results suggest that the PLSR model based on full-band SNV processed spectra shows the best performance for predicting pymetrozine and carbendazim contents, with R2 of 0.

Investigation of the adsorption of pymetrozine on the Au@AgNPs surface and its application in the rapid detection of pymetrozine residues in apple.

Pymetrozine is widely used in agriculture to control pests, and its residue may pose a threat to humans. In this study, the adsorption behavior of pymetrozine on Au@AgNPs surfaces in different solutions was investigated by calculation of ACD/Labs, density functional theory, UV-vis spectra, zeta potential and surface-enhanced Raman scattering. Then, a SERS method for detection of pymetrozine residues in apples was established based on the adsorption study.

Real-time and in situ monitoring of organosilicon-induced thiram penetration into cabbage leaves by surface-enhanced Raman scattering mapping.

Background: Understanding pesticide penetration behavior is important for effective application of pesticides. However, there is a lack of an effective method to monitor pesticide penetration behavior and its changing process. In the present study, a novel surface-enhanced Raman scattering (SERS) mapping method was used for real-time and in situ tracking of the penetration behaviors of thiram and thiram-organosilicon mixture on cabbage leaves.

Degradation of Sulfoxaflor in Water and Soil: Kinetics, Degradation Pathways, Transformation Product Identification, and Toxicity.

Hydrolysis, photolysis, and soil degradation are important degradation pathways of pesticides and might generate toxic chemicals and pose threats to the environment. Sulfoxaflor is a widely used neonicotinoid pesticide, but few studies have been conducted to research its environmental behaviors and residues. Herein, the hydrolysis and photolysis of sulfoxaflor in water and degradation in four typical Chinese soils were systematically studied.

A Sensitive SERS Method for Determination of Pymetrozine in Apple and Cabbage Based on an Easily Prepared Substrate.

Residual pesticides are one of the major food safety concerns around the world. There is a demand for simple and reliable methods to monitor pesticide residues in foods. In this study, a sensitive method for determination of pymetrozine in apple and cabbage samples using surface-enhanced Raman spectroscopy (SERS) based on decanethiol functionalized silver nanoparticles was established.

In situ and rapid determination of acetamiprid residue on cabbage leaf using surface-enhanced Raman scattering.

Background: Pesticide residues in agricultural products and foods pose a serious threat to human health, and therefore a simple, rapid and direct method is urgently needed for pesticide residue detection. In addition to realizing the detection of acetamiprid in cabbage extract solution, the main target of this study was to establish an in situ surface-enhanced Raman scattering (SERS) method, which could directly detect acetamiprid residue on cabbage leaf without the need for extraction. Acetamiprid was first used to contaminate the surface of fresh cabbage leaf, and then bimetallic silver-coated gold nanoparticles (Au@AgNPs) were added on the contaminated spots and dried for SERS measurement.

New Method for Accurate Determination of Polyphenol Oxidase Activity Based on Reduction in SERS Intensity of Catechol.

Rapid and accurate measurement of polyphenol oxidase (PPO) activity is important in the food industry as PPOs play a vital role in catalyzing enzymatic reactions. The aim of this study was to develop surface-enhanced Raman scattering (SERS) approach for accurate determination of PPO activity in fruit and vegetables using the reduction in SERS intensity of catechol in reaction medium. Within a certain catechol concentration, when a purified PPO solution was analyzed, the reduction in SERS intensity (Δ I) was linear to PPO activity ( E) in a wide range of 500-50 000 U/L, and a linear regression equation of log Δ I/Δ t = 0.

Simple Approach for the Rapid Detection of Alternariol in Pear Fruit by Surface-Enhanced Raman Scattering with Pyridine-Modified Silver Nanoparticles.

A simple method based on surface-enhanced Raman scattering (SERS) was developed for the rapid determination of alternariol (AOH) in pear fruits using an easily prepared silver-nanoparticle (AgNP) substrate. The AgNP substrate was modified by pyridine to circumvent the weak affinity of the AOH molecules to the silver surface and to improve the sensitivity of detection. Quantitative analysis was performed in AOH solutions at concentrations ranging from 3.

Recent Developments in Methods and Techniques for Rapid Monitoring of Sugar Metabolism in Fruits.

The major sugars in fruits, including glucose, fructose, and sucrose, play a critical role in fruit quality control and maturity evaluation. Many novel methods and techniques such as enzymatic and nonenzymatic biosensors, nuclear magnetic resonance, and near-infrared spectroscopy have been developed to provide the rapid estimation of sugar inversion under different storage conditions. This review provides a description of recent advancements in these technologies for the determination of sugar contents in fruits.

Regression Algorithms in Hyperspectral Data Analysis for Meat Quality Detection and Evaluation.

Hyperspectral imaging (HSI) system in tandem with chemometric methods is proposed as a rapid, efficient, cost-saving, and nondestructive detection technique, and multivariate data analysis is an indispensable part of this novel detection technique. In recent years, the rapid progress that we have made in using all kinds of chemometric methods to deal with hyperspectral data of meat products, however, cannot meet the practical needs very well. Thus, in order to give some suggestions on how to select an appropriate algorithm for hyperspectral data analysis, this review, first, briefly introduces the principle of the most widely used regression algorithms, and, more importantly, then focuses on the application of different algorithms in modeling the correlation between the quality attributes of the tested sample and their hyperspectral data.

Synergetic degradation of konjac glucomannan by γ-ray irradiation and hydrogen peroxide.

Konjac glucomannan (KGM) samples were irradiated with (60)Co γ-rays with a radiation dose of 50kGy in the presence and absence of hydrogen peroxide. The average molecular weight (Mw) and polydispersity index (PDI) of untreated and degraded samples were measured by gel permeation chromatography (GPC), revealing that γ-rays and hydrogen peroxide had a synergetic effect on degradation. Structures of untreated and degraded products were characterized with ultraviolet-visible (UV) and Fourier-transform infrared (FT-IR) spectroscopies, and X-ray diffraction (XRD).

Study on preparation and separation of Konjac oligosaccharides.

To study the preparation and separation of Konjac oligosaccharides, Konjac Glucomannan was degraded by the combination of γ-irradiation and β-mannanase, and then the degradation product was separated by ultrafiltration. To our interest, for most of Konjac oligosaccharides obtained by this method, the molecular mass was lower than 2200 Da. In addition, the 1000 Da molecular weight cut off membrane could effectively separate the Konjac oligosaccharides.