In this work we investigate the performance of a simple, disposable electrochemical aptasensor for lysozyme and its usefulness for monitoring the allergen risk along wine production. The sensor relies on screen‐printed gold electrodes modified with gold nanoparticles as the electrochemical transducer, with detection by cyclic voltammetry. This simple method is characterized by a detection limit of 0.32 μg.mL−1 lysozyme and a linear range of 1–10 μg.mL−1, being appropriate for the analysis of lysozyme‐treated wines. Several white wines where sulphur dioxide was partially replaced by lysozyme were produced and analyzed with the aptasensor at critical stages during wine production. The results obtained with the aptasensor were moreover compared with those recorded in parallel by a standard method, high performance liquid chromatography (HPLC). The specific advantages brought by the use of nanomaterial and the limitations of the sensor are discussed. The sensor allowed evaluating the effect of various technological steps along wine production on the content of lysozyme.
Electrochemical sensors and biosensors have been proposed as fast and cost effective analytical tools, meeting the robustness and performance requirements for industrial process monitoring. In wine production, electrochemical biosensors have proven useful for monitoring critical parameters related to alcoholic fermentation (AF), malolactic fermentation (MLF), determining the impact of the various technological steps and treatments on wine quality, or assessing the differences due to wine age, grape variety, vineyard or geographical region. This review summarizes the current information on the voltamperometric biosensors developed for monitoring wine production with a focus on sensing concepts tested in industry-like settings and on the main quality parameters such as glucose, alcohol, malic and lactic acids, phenolic compounds and allergens. Recent progress featuring nanomaterial-enabled enhancement of sensor performance and applications based on screen-printed electrodes is emphasized. A case study presents the monitoring of alcoholic fermentation based on commercial biosensors adapted with minimal method development for the detection of glucose and phenolic compounds in wine and included in an automated monitoring system. The current challenges and perspectives for the wider application of electrochemical sensors in monitoring industrial processes such as wine production are discussed.
Aflatoxins, which are mainly produced by Aspergillus flavus and parasiticus growing on plants and products stored under inappropriate conditions, represent the most studied group of mycotoxins. Contamination of human and animal milk with aflatoxin M1, the hydroxylated metabolite of aflatoxin B1, is an important health risk factor due to its carcinogenicity and mutagenicity. Due to the low concentration of this aflatoxin in milk and milk products, the analytical methods used for its quantification have to be highly sensitive, specific and simple. This paper presents an overview of the analytical methods, especially of the electrochemical immunosensors and aptasensors, used for determination of aflatoxin M1.
Flexible screen-printed electrodes (SPE) were modified in a simple manner with different composite nanomaterials based on carbon allotropes, polymers, and metallic nanoparticles, for amperometric detection of nitrites in soil. Multiwalled carbon nanotubes (MWCNT), chitosan (CS), silver nanoparticles (AgNPs), 1,8-diaminonaphthalene (1,8-DAN), and a sol-gel (SG) matrix were used for modification of the carbon paste working electrodes. Sensitive and selective detection of nitrite was achieved by using a MWCNT-CS-modified sensor, in acetate buffer at pH 5, at an applied potential of 0.58 V vs. Ag/AgCl. The MWCNT-CS-based sensor displayed a specific sensitivity of 204.4 mA·M−1·cm−2, with a detection limit of 2.3 µM (S/N = 3) in a linear range up to 1.7 mM, showing good stability, reproducibility, and selectivity towards other interfering species. A miniaturized portable system using the developed flexible electrochemical MWCNT-CS-based sensors was dedicated for the detection of nitrite in different samples of soil solutions extracted by using suction lysimeters.
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