Determination of Biogenic Amines in Cheese by On-line Solid Phase Extraction Coupled with Capillary High Performance Liquid Chromatography

Research progress of the combination of COFs materials with food safety detection

Covalent organic frameworks (COFs) have received lots of attention due to their multiple advantages such as high specific surface area, controlled pore size, and excellent stability. When detecting food contaminants, the matrix effect brought by complex food samples can significantly affect the accuracy of the results. How to attenuate matrix effect has always been a major challenge. Utilizing the advantages of COFs and applying them to detect food contaminants is currently a key research direction. The aim of this work is to provide a systematic summary of sample pretreatment techniques and detection techniques combined with COFs, which include almost all current techniques combined with COFs. In addition, the principles of combining COFs with different techniques are explained. Finally, the research foci and development direction of COFs in food contaminant detection are discussed. This is an important reference for the future development of food safety and the design of COFs.

Modern automated microextraction procedures for bioanalytical, environmental, and food analyses

Sample preparation frequently is considered the most critical stage of the analytical workflow. It affects the analytical throughput and costs; moreover, it is the primary source of error and possible sample contamination. To increase efficiency, productivity, and reliability, while minimizing costs and environmental impacts, miniaturization and automation of sample preparation are necessary. Nowadays, several types of liquid-phase and solid-phase microextractions are available, as well as different automatization strategies. Thus, this review summarizes recent developments in automated microextractions coupled with liquid chromatography, from 2016 to 2022. Therefore, outstanding technologies and their main outcomes, as well as miniaturization and automation of sample preparation, are critically analyzed. Focus is given to main microextraction automation strategies, such as flow techniques, robotic systems, and column-switching approaches, reviewing their applications to the determination of small organic molecules in biological, environmental, and food/beverage samples.

Supersensitive detection of single-histamine molecule on nanoplates by turn-on small molecule fluorescence sandwich immunoassay

We develop a supersensitive "turn-on format" fluorescence sandwich immunoassay for detecting small single molecules. Gold nanoplate-based biotin antibodies and streptavidin-fluorophores were used instead of streptavidin-horseradish peroxidase reacting with a biotin tracer in a microplate-based competitive enzyme-linked immunosorbent assay (ELISA). Our platform showed a low detection limit of 5 zeptomolar (5 × 10^-21 M), 5.4 × 10¹⁰ times higher detection sensitivity than the conventional tune-off format ELISA.

Fabrication of a ratiometric electrochemiluminescence biosensor using single self-enhanced nanoluminophores for the detection of spermine

A ratiometric electrochemiluminescence strategy using a single luminophore for accurate and sensitive biomolecule detection could be immensely valuable in bioanalysis. Herein, an ultrasensitive ratiometric electrochemiluminescence sensing system was fabricated using a self-enhanced luminophore with dual-signal emission for the detection of spermine. A nanocomposite was synthesized by the covalent attachment of N, N-diisopropylethylenediamine onto glutathione-protected Au-Ag bimetallic nanoclusters (DPEA-GSH@Au/Ag BNCs). The nanocomposite exhibited efficient intra-cluster charge transfer to produce strong anodic self-enhanced electrochemiluminescence emission at 0.8 V without external co-reactants. Interestingly, the DPEA@GSH@Au-Ag BNCs exhibited cathodic electrochemiluminescence emission upon the addition of the co-reactant potassium persulfate at -1.6 V, exhibiting stable and efficient dual-signal electrochemiluminescence emission features at a continuous potential window of -1.75 to 1.2 V. Thus, they were used to fabricate a single-luminophore electrochemiluminescence sensor with dual emission. The cathodic emission of the biosensor gradually increased with increasing concentrations of spermine, whereas the anodic electrochemiluminescence intensity remained almost constant, enabling the ratiometric detection of spermine. The fabricated biosensor, with an internal standard, significantly improved the accuracy and reliability of spermine detection in a wide concentration range of 0.85 pM-100 μM, with a low limit of detection of 0.12 pM (S/N = 3) under optimum conditions. This single-luminophore electrochemiluminescence sensing system could be used for the detection of spermine and could guide the construction of ratiometric electrochemiluminescence sensors in the future.

Biogenic Amines Formation Mechanism and Determination Strategies: Future Challenges and Limitations

The evolution in foodstuff-monitoring processes has increased the number of studies on biogenic amines (BAs), in recent years. This trend with future perspective needs to be assembled to address the associated health risks. Thus, this study aims to cover three main aspects of BAs: (i) occurrence, physiology, and toxicological effects, most probable formation mechanisms and factors controlling their growth; (ii) recent advances, strategies for determination, preconcentration steps, model technique, and nature of the matrix; and (iii) milestone, limitations with existing methodologies, future trends, and detailed expected developments for clinical use and on-site ultra-trace determination. The core of the ongoing review will discuss recent trends in pre-concentration toward miniaturization, automation, and possible coupling with electrochemical techniques, surface-enhanced Raman scattering, spectrofluorimetry, and lateral flow protocols to be exploited for the development of rapid, facile, and sensitive on-site determination strategies for BAs.