Abstract

Cost-effective chemosensors have become an indispensable tool for sustainable monitoring in food safety and processing, where there is an urgent need for affordable, efficient, and real-time analytical solutions. This review discusses recent advances in low-cost chemosensor technologies, highlighting developments in materials, miniaturization, and integration into portable and accessible platforms. The focus is on applications for detecting contaminants, monitoring quality, and ensuring safety in food production and processing. This review also addresses the challenges related to sensor sensitivity, selectivity, and operational stability and provides insights into future directions and the role of low-cost chemosensors in supporting sustainable practices in these important sectors.

Abstract

The purpose of this study was to extract the lipophilic fraction from one of the largest source of waste in the industrial sector, namely, the tomato residue from processing the fruit. In order to make this process more environmentally sustainable, this study used a green extraction protocol employing natural deep eutectic solvents (NADESs) combined with a less energy-consuming technology, the ultrasound-assisted extraction (UAE) method, to simultaneously recover carotenoids and tocopherol from dried powder tomato waste. Two NADESs, one hydrophilic and one hydrophobic, were prepared and compared to support high extraction efficiency and increase the stability of the extracted compounds. The optimal extraction parameters were identified as choline chloride:1,3-butanediol (1:5)-based NADES, a solid-to-liquid ratio of 1:20 (w/v), time of extraction 12 min, temperature 65 degrees C, radiation frequency 37 Hz, and an ultrasound power level of 70%. The extraction process was intensified and resulted in extracts rich in lycopene (215.13 +/- 4.31 mu g/g DW), beta-carotene (206.95 +/- 3.27 mu g/g DW), and tocopherol (130.86 +/- 8.97 mu g/g DW) content, with the highest antioxidant capacity 93.84 +/- 0.18 mM Trolox equivalent. Incorporating NADESs for the extraction of bioactive compounds offers numerous benefits, such as improved sustainability, enhanced extraction efficiency, better protection of sensitive compounds, and reduced environmental impact. These advantages make NADESs a promising alternative to traditional organic solvents, especially in industries that require natural, green, and efficient extraction processes for valuable bioactive molecules.

Abstract

A nitrogen-doped nanocrystalline electrochemical graphite sensor for the sensitive determination of oleuropein (OL) from extra virgin olive oils (EVOOs) is presented. The sensor was developed by the deposition of nanocrystalline graphite (NCG) using plasma-enhanced chemical vapour deposition (PECVD) on silicon wafers. Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction analysis (XRD) were used to characterise the microstructure and morphology of the developed materials. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV) were used to investigate the electrochemical properties of the material and the performance of the sensor. The developed sensor showed good analytical performance against OL over a concentration range of 5.00-500.00 mu M, with a good detection limit of 3.93 mu M and a good sensitivity of 0.057 mu A mu M-1. The reproducibility of the electrochemical sensor was excellent, with a relative standard deviation (RSD) of 8.56% for seven measurements.

Abstract

Phenyl aldehyde layers were formed on copper foils by electro-assisted diazonium reactions and subsequently functionalized with either amino-2-propanol or 2-amino-1-butanol. The anticorrosion properties of the two obtained organic films 2-[(phenylmethylidene)amino]butan-1-ol and (phenylmethylidene)amino-propan-2-ol were evaluated in aerated buffer acetate solution pH = 3.5. The electrochemical corrosion inhibition properties were investigated after different immersion times using electrochemical impedance spectroscopy and potentiodynamic polarization analysis (Tafel). Contact angle measurement confirms the hydrophobic nature of the new organic coatings and layer stability after immersion in buffer. The results showed that both developed layers provided good anticorrosion protection and the highest inhibition was achieved using 2-[(phenylmethylidene)amino]butan-1-ol coating on copper, which makes it a useful device for anticorrosion protection. Moreover, correlations between the molecular structures of the corrosion inhibitors and their protecting efficiencies have been established.

Abstract

Phenyl aldehyde layers were formed on copper foils by electro-assisted diazonium reactions and subsequently functionalized with either amino-2-propanol or 2-amino-1-butanol. The anticorrosion properties of the two obtained organic films 2-[(phenylmethylidene)amino]butan-1-ol and (phenylmethylidene)amino-propan-2-ol were evaluated in aerated buffer acetate solution pH Æ 3.5. The electrochemical corrosion inhibition properties were investigated after different immersion times using electrochemical impedance spectroscopy and potentiodynamic polarization analysis (Tafel). Contact angle measurement confirms the hydrophobic nature of the new organic coatings and layer stability after immersion in buffer. The results showed that both developed layers provided good anticorrosion protection and the highest inhibition was achieved using 2-[(phenylmethylidene)amino]butan-1-ol coating on copper, which makes it a useful device for anticorrosion protection.Moreover, correlations between the molecular structures of the corrosion inhibitors and their protecting efficiencies have been established. © 2021 Elsevier Masson SAS. All rights reserved.

Abstract

Phenyl aldehyde layers were formed on copper foils by electro-assisted diazonium reactions and subsequently functionalized with either amino-2-propanol or 2-amino-1-butanol. The anticorrosion properties of the two obtained organic films 2-[(phenylmethylidene)amino]butan-1-ol and (phenylmethylidene)amino-propan-2-ol were evaluated in aerated buffer acetate solution pH Æ 3.5. The electrochemical corrosion inhibition properties were investigated after different immersion times using electrochemical impedance spectroscopy and potentiodynamic polarization analysis (Tafel). Contact angle measurement confirms the hydrophobic nature of the new organic coatings and layer stability after immersion in buffer. The results showed that both developed layers provided good anticorrosion protection and the highest inhibition was achieved using 2-[(phenylmethylidene)amino]butan-1-ol coating on copper, which makes it a useful device for anticorrosion protection.Moreover, correlations between the molecular structures of the corrosion inhibitors and their protecting efficiencies have been established. © 2021 Elsevier Masson SAS. All rights reserved.

Abstract

Abstract

Copper substrates deposed on a gold screen-printed electrodewere coveredwith different aryl diazonium salts by electrodeposition at 0.25 mA for 30 or 300 s. Seven compounds were investigated: 4-aminophenylacetic acid, 4-aminophenethyl alcohol, 4-fluoroaniline, 4-(heptadecafluorooctyl) aniline, 4-aminoantipyrine, 4-(4-aminophenyl) butyric acid and 3,4,5-trimethoxyaniline. Quantitative monitoring of the electrodeposition process was carried out by electrogravimetry using quartz crystal microbalance (QCM). The electrodeposited mass varies between 26 ng/cm(2) for 4-fluoroaniline formed during 30 s to 442 ng/cm(2) for 4-phenylbutyric acid formed during 300 s. The corrosion inhibition properties of aryl-modified layers have been studied in buffer citrate with pH = 3 or 3.5% NaCl solutions using electrochemical noise (ECN) and Tafel potentiodynamic polarization measurements. A corrosion inhibiting efficiency up to 90% was found. The highest corrosion inhibition was obtained for 4-(4-aminophenyl) butyric acid and the lowest for 4-fluoroaniline. A relation between the inhibition efficiency and the chemical nature of the substituents in the protective layer was found.

Abstract

Abstract

Some plants collected (Mentha aquatica, Bidens tripartita and Ambrosia artemisiifolia) from an unusual habitat developed in recent years in Bucharest (the so-called "Bucharest Delta") and the contents of polyphenolic compounds, short-chain organic acids and heavy metals, and radical scavenger activity, were determined. 12 polyphenolic compounds and 7 short-chain organic acids were quantified using high-performance liquid chromatography and capillary electrophoresis; Mentha aq. extracts presented the highest levels of rosmarinic acid (1.58 mg g-1) and ferulic acid (2.84 mg g-1) and Bidens extracts presented the highest concentrations of chlorogenic acid (0.44 mg g-1); the same extracts contain the most important levels of luteolin (0.52 mg g-1) or other flavonoids. All the heavy metals detected in the plants studied were found in very low levels (the highest was Pb(II) in Mentha aquatica, (12.84 ± 0.48) μg kg-1). The study sought to identify the active compounds and some contaminants in plants collected from the "Bucharest Delta" with the intention of eventual exploitation of the habitat and to enhance the knowledge of such human-modified ecosystems. © 2015 Institute of Chemistry, Slovak Academy of Sciences.