Cold plasma is an emerging non-thermal disinfection and surface modification technology which is chemical free, and eco-friendly. Plasma treatment of water, termed as plasma activated water (PAW), creates an acidic environment which results in changes of the redox potential, conductivity and in the formation of reactive oxygen (ROS) and nitrogen species (RNS). As a result, PAW has different chemical composition than water and can serve as an alternative method for microbial disinfection.This paper reviews the different plasma sources employed for PAW generation, its physico-chemical properties and potential areas of PAW applications. More specifically, the physical and chemical properties of PAW are outlined in relation to the acidity, conductivity, redox potential, and concentration of ROS, RNS in the treated water. All these effects are in microbial nature, so the applications of PAW for microbial disinfection are also summarized in this review. Finally, the role of PAW in improving the agricultural practices, for example, promoting seed germination and plant growth, is also presented.PAW appears to have a synergistic effect on the disinfection of food while it can also promote seedling growth of seeds. The increase in the nitrate and nitrite ions in the PAW could be the main reason for the increase in plant growth. Soaking seeds in PAW not only serves as an anti-bacterial but also enhances the seed germination and plant growth. PAW could potentially be used to increase crop yield and to fight against the drought stress environmental conditions.

External corrosion of tinplate cans containing food products, although less frequent and comparatively less dangerous than internal corrosion, should anyhow be studied more in depth, since the consumer requires not only high-quality products, but also cans having a good appearance. The objective of this experimental work was to study the influence of the main ions present in cooling waters on the corrosion of metal food cans. After a short introduction on tinplate corrosion phenomena and on the chemical and processing factors affecting it, the results are shown which were obtained from electrochemical corrosion trials performed using model solutions at various concentrations as well as cooling water samples directly taken from food plants. This research work yielded information on the corrosion mechanisms (extent and morphology) of the various species and parameters affecting the aggressivity of industrial waters (presence of additives, free chlorine content and conductivity) | La corrosione esterna delle scatole di banda stagnata contenenti prodotti alimentari, sebbene meno frequente e relativamente meno pericolosa della corrosione interna, deve comunque essere oggetto di maggiore attenzione, in quanto il consumatore richiede, oltre a prodotti di alta qualita', contenitori di aspetto accettabile. Oggetto del lavoro sperimentale e' stato lo studio dell'influenza dei principali ioni presenti nelle acque di raffreddamento sulla corrosione delle scatole metalliche per alimenti. Dopo una breve introduzione sui fenomeni di corrosione della banda stagnata e sui fattori chimici e di processo che la condizionano, il lavoro illustra i risultati ottenuti nelle prove di corrosione elettrochimiche effettuate con soluzioni modello a diverse concentrazioni e con acque di raffreddamento prelevate direttamente presso industrie alimentari. A conclusione della ricerca sono state ottenute informazioni sul meccanismo di corrosione (intensita' e morfologia) delle diverse specie e sui parametri che influenzano l'aggressivita' delle acque industriali (presenza di additivo, concentrazione di cloro libero e conducibilita')

A new electrochemical adsorptive stripping voltammetry method was developed for the determination of trace amounts of copper in food and water samples. The study of electrochemical behavior of Cu ion indicated that Cu(II) and Schiff base formed a complex in H3BO4-NaOH buffer solution (pH = 7.25). An accumulation potential of -100 mV (vs Ag/AgCl) was applied while the solution was stirred for 60 s. The response curve was recorded by scanning the potential, and the peak current of -0.31 V (vs Ag/AgCl) was recorded. The peak current and concentration of copper accorded with linear relationship in the range of 0.04-120 ng mL(-1). The relative standard deviation (for 12 ng mL(-1) of copper) was 1.73 %, and the detection limit was 0.007 ng mL(-1). The possible interference of some common ions was studied. The proposed method was applied to the determination of copper in water, rice, wheat, tea, milk, and tomato with satisfactory results.

In this study, Hg²⁺ ions were found to quench the fluorescence of glutathione (GSH)-capped copper clusters (Cu NCs). The Cu NCs were prepared by a simple reduction of CuSO4 in the presence of GSH serving both as a reducing and protecting agents, and characterized by ultraviolet–visible absorption spectroscopy (UV–vis), high resolution scanning electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectrometer (XPS). The GSH-Cu NCs displayed a small size, excellent water-dispersibility, good storage stability, good photostability and were stable in the presence of high concentrations of salt. The GSH-Cu NCs possessed strong blue fluorescence with a quantum yield of 10.6% and exhibited an excitation-independent fluorescence behavior. The zeta potential, TEM, resonance light scattering and dynamic light scattering measurements demonstrated that the Hg²⁺ ion-induced aggregation of the Cu NCs contributed to the fluorescence quenching of the dispersed Cu NCs. On these findings, a sensitive and selective fluorescent probe was developed for detecting Hg²⁺ in the linear range from 10nM to 10μM with a detection limit of 3.3nM (S/N=3). The proposed method has been successfully applied to determine Hg²⁺ content in water sample and food stuff. The results of the proposed method were in good agreement with those obtained by a hydride generation atomic fluorescence spectrometry (HG-AFS).

Luminescent Tb³⁺ functionalized metal–organic frameworks (MOFs) are prepared and act as food preservatives sensor and water scavenger for NO₂–. Classical metal–organic frameworks with uncoordinated N atoms in pores are elected as carrier to encapsulate Tb³⁺ ions. This Tb³⁺ incorporated material reveals excellent characteristic green luminescence of Tb³⁺ and good fluorescence stability in water. Subsequently, we choose this probe for sensing NO₂– among several food preservative compounds, showing a highly sensitive capability for detection of NO₂–; it is then proved that the Dexter energy transfer (DET) causes the luminescent quenching between Tb³⁺ and NO₂–, achieving the detection of NO₂–. This probe is also employed to detect the NO₂– in real water samples and act as water scavenger to remove the NO₂– in drinking water, showing a good removal capacity 3.45 mg (75.0 μmol) of NO₂– per gram of particles.

In this study, ultralayered Co₃O₄ adsorbent was synthesized and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The surface area of the solid material was found to be 75.5m²g⁻¹ by BET method. The ultralayered Co₃O₄ was used for the first time as an effective adsorbent for the preconcentration of the Pb(II) ions in various samples prior to flame atomic absorption detection. Analytical parameters affecting the solid phase extraction of Pb(II) such as pH, adsorption and elution contact time, eluent volume and concentration, sample volume and common matrix ions were investigated. The recovery values for Pb(II) were found to be ≥92% even in the presence of 75,000mgL⁻¹ Na(I), 75,000mgL⁻¹ K(I), and 75,000mgL⁻¹ Ca(II) ions. 10s vortexing time was enough for both adsorption and elution contact times. The elution was easily made with 2mL of 2.0molL⁻¹ HNO₃. The reusability (170 cycles) and adsorption capacity (35.5mgg⁻¹) of ultralayered Co₃O₄ were excellent. The preconcentration factor of the method and detection limit were found to be 175 and 0.72µgL⁻¹, respectively. The described method was validated with certified reference material (RM 8704 Buffalo River Sediment, BCR-482 Licken and SPS-WW1 Batch 111-Wastewater) and spiked real samples. It was also applied for the preconcentration of Pb(II) ions in various water (well water, mineral water, waste water and sea water), food (cauliflower and barley), street sediment and tobacco samples.

A new bio-MSPE sorbent based on the use of C. micaceus and γ-Fe₂O₃ magnetic nanoparticle was prepared for the preconcentrations of Co(II) and Hg(II). Critical parameters including pH, flow rate, quantity of C. micaceus, quantity of γ-Fe₂O₃ magnetic nanoparticle, eluent (type, concentration and volume), sample volume, and foreign ions were examined. Surface structure and variations after interaction with Co(II) and Hg(II) of bio-MSPE sorbent were investigated by FT-IR, SEM, and EDX. The impact of bio-MSPE column reusage was also tested. The biosorption capacities were determined as 24.7 mg g⁻¹ and 26.2 mg g⁻¹, respectively for Co(II) and Hg(II). Certified reference materials were utilized to find out the accuracy of the prepared bio-MSPE method. This novel bio-MSPE method was accomplished by being applied to real food and water samples. In particular, it will be possible to make use of C. micaceus as new alternatives, in environmental biotechnology applications.

To develop an accurate and precise method for separation and pre-concentration of Hg(II), a novel thionin functionalised core shell structure magnetic material has been prepared and characterised. The extraction ability of the material was evaluated by magnetic solid-phase extraction coupled with inductively coupled plasma mass spectrometry determination of Hg(II) in food and water samples. Combining the advantages of magnetic separation with selective extraction of thionin towards Hg(II), the material exhibits enhanced enrich selectivity and efficiency for Hg(II). The experimental parameters influencing Hg(II) extraction efficiency, including pH of the aqueous solution, the dosage of the adsorbent, extraction time and sample volume, were systematically investigated. Under the optimised conditions, concentration of Hg(II) at 1.0 μg L⁻¹ can be successfully enriched by the material without the interference of the common co-existing ions. The enrichment factor and adsorption capacity were 250 and 75.2 mg g⁻¹, and precise of the method was confirmed by analysing the spiked food, water samples and standard water reference samples with the recoveries of 92.5–101.8%.

A simple and rapid vortex-assisted magnetic solid phase extraction (VA-MSPE) method for the separation and preconcentration of ziram (zinc dimethyldithiocarbamate), subsequent detection of the zinc in complex structure of ziram by flame atomic absorption spectrometry (AAS) has been developed. The ziram content was calculated by using stoichiometric relationship between the zinc and ziram. Magnetic carboxylated nanodiamonds (MCNDs) as solid-phase extraction adsorbent was prepared and characterized by Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD) spectrometry and scanning electron microscopy (SEM). These magnetic carboxylated nanodiamonds carrying the ziram could be easily separated from the aqueous solution by applying an external magnetic field; no filtration or centrifugation was necessary. Some important factors influencing the extraction efficiency of ziram such as pH of sample solution, amount of adsorbent, type and volume of eluent, extraction and desorption time and sample volume were studied and optimized. The total extraction and detection time was lower than 10min The preconcentration factor (PF), the precision (RSD, n=7), the limit of detection (LOD) and limit of quantification (LOQ) were 160, 7.0%, 5.3µgL−1 and 17.5µgL−1, respectively. The interference of various ions has been examined and the method has been applied for the determination of ziram in various waters, foodstuffs samples and synthetic mixtures.