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Topic Review
Total Polyphenol Content in Food Samples and Nutraceuticals
Total polyphenol content and antioxidant capacity were estimated in various food and nutraceutical samples. These were analyzed by using two antioxidant assays—ferric reducing antioxidant power (FRAP) and Folin–Ciocalteu (FC)—and a reversed-phase high performance liquid chromatography (HPLC), with a focus on providing compositional fingerprints dealing with polyphenolic compounds. A preliminary data exploration via principal component analysis (PCA) revealed that HPLC fingerprints were suitable chemical descriptors to classify the analyzed samples according to their nature. Moreover, chromatographic data were correlated with antioxidant data using partial least squares (PLS) regression.
  • 485
  • 06 Apr 2022
Topic Review
The SIFT-MS Technique
Selected ion flow tube mass spectrometry (SIFT-MS) uses soft chemical ionization (CI) to generate mass-selected reagent ions that can rapidly react with and quantify VOCs down to part-per-trillion concentrations (by volume, pptV). Up to eight reagent ions (H3O+, NO+, O2+, O-, OH-, O2-, NO2- and NO3-) obtained from a microwave discharge in air are available on SIFT-MS instruments. These reagent ions react with VOCs and other trace analytes in well-controlled ion-molecule reactions, but they do not react with the major components of air (N2, O2, CO2 and Ar). This enables direct, real-time analysis of air samples to be achieved at trace and ultra-trace levels without pre-concentration. Rapid switching between reagent ions provides high selectivity because the multiple reaction mechanisms give independent measurements of each analyte. 
  • 526
  • 28 Apr 2023
Topic Review
The Sensing Techniques for Formaldehyde Detection
Formaldehyde has been regarded as a common indoor pollutant and does great harm to human health, which has caused the relevant departments to pay attention to its accurate detection. Spectrophotometry, gas chromatography, liquid chromatography, and other methods have been proposed for formaldehyde detection. Among them, the gas sensor is especially suitable for common gaseous formaldehyde detection with the fastest response speed and the highest sensitivity. 
  • 387
  • 28 Feb 2023
Topic Review
The Metabolomics Approaches for Analysis of Non-Halal Meats
Halal meats are meats that are allowed to be consumed by Muslim societies according to Islamic law (Syariah). Due to the development of food technology, non-halal meats such as pork or canine meat are added to food products to reduce the production costs. Non-halal meats also include meats from animals which are not slaughtered according to Syariah law; therefore, the availability of a standardized analytical method capable of detecting the presence of non-halal meats with high sensitivity is very urgent. The metabolomics technique, either targeted or untargeted approaches based on liquid chromatography–tandem mass spectrometry (LC-MS/MS) measurements is an emerging analytical method applied to the identification of non-halal meats in food products. The LC-MS/MS measurements provide an enormous metabolomics data, therefore, sophisticated data analysis tools such as chemometrics is required.
  • 571
  • 19 Jul 2022
Topic Review
The Mammalian Thioredoxin Reductase Probes
The cardinal component of the thioredoxin system, mammalian thioredoxin reductase (TrxR) plays a vital role in supporting various physiological functions; however, its malfunction, disrupting redox balance, is intimately associated with the pathogenesis of multiple diseases. Fluorescent probes offer several advantages for in situ imaging and the quantification of biological targets, such as non-destructiveness, real-time analysis, and high spatiotemporal resolution. These benefits facilitate the transition from a poise to a flux understanding of cellular targets, further advancing scientific studies in related fields. The TrxR fluorescent probes have contributed significantly to the investigation of TrxR’s biological functions and have been valuable tools in TrxR-related research.
  • 109
  • 24 Aug 2023
Topic Review
The Design Principle of SERS Nanotags
Surface-enhanced Raman scattering (SERS) is an emerging spectroscopic technology. By integrating with nanotechnology (e.g., noble metal nanoparticles), SERS allows 106–1015 Raman signal amplification and thus sensitive sensing down to single molecules. In addition, SERS possesses extremely narrow Raman spectral line widths (i.e., ~1 nm), which are about 50 times narrower than the commonly used fluorescence bands.
  • 360
  • 25 Apr 2023
Topic Review
The Chemical Fingerprint of Fortified Wines
The chemical fingerprint of fortified wines is very complex and fascinating, being constituted by several hundred volatile and non-volatile chemical groups, such as terpenoids, pyrazines, esters, alcohols, acids, furanic compounds, phenolic compounds, and organic acids, among others. These chemical groups were present in fortified wines at different volatilities, polarities, and concentration ranges, from a few ng/L to mg/L. However, the quality of wine also depends on several parameters, such as grape variety, vineyard location, terroir, and vinification conditions (e.g., fermentation, ageing), among others. 
  • 482
  • 12 Jul 2023
Topic Review
The Advances of Hydrosol–Gel Transition-Based Sensors
Hydrogels, as a type of three-dimensional porous material, have attracted a lot of attention in the fields of drug delivery, artificial tissue engineering, and sensing. Due to their excellent biocompatibility and high sensitivity to external stimuli, they are widely used in the development of various sensors. Among them, the sensors constructed based on the sol–gel transition of target–responsive hydrogels are particularly welcome. The status of the sensors on the basis of sol–gel transition has been presented. The types of hydrogel sensors and the analytical methods in various application scenarios are illustrated. In addition, the future trends of the sensing systems based on sol–gel transition are briefly discussed. 
  • 380
  • 20 Oct 2022
Topic Review
Techniques for the Analysis of Trace Tin Concentrations
Tin determination allows for the monitoring of pollution and assessment of the impact of human activities on the environment. The determination of tin in the environment is crucial for the protection of human health and ecosystems, and for maintaining sustainability. Tin can be released into the environment from various sources, such as industry, transportation, and electronic waste. The concentration of tin in the environment can be determined by different analytical methods, depending on the form of tin present and the purpose of the analysis. The choice of an appropriate method depends on the type of sample, concentration levels, and the available instrumentation.
  • 99
  • 18 Dec 2023
Topic Review
Targeted Metabolomics Induced by Microplastics
It has been reported that microplastics (MPs)  are present in several organs in different species, including the liver, intestines, kidney, and other organs, where they have the potential to cause detrimental effects such as disrupting endocrine regulation, neurotoxicity, and reproductive toxicity. Therefore, metabolomics studies have attracted considerable attention from researchers who are eager to reveal the mechanism behind the biomarkers that have been discovered by serum chemistry tests, histological tests, or polymerase chain reaction (PCR) analyses. Metabolomics studies can be achieved in two ways, namely targeted and untargeted. Targeted metabolomics detects defined groups of metabolites, providing quantitative results with a high degree of sensitivity and data quality. The advantage of targeted metabolomics is that a complicated data process is not required, but that relatively limited information can be obtained in a single analysis. 
  • 260
  • 05 May 2023
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