Vegetable Samples Research Articles

Monoclonal antibody-based icELISA for sensitive monitoring fenpyroximate residue by hydrolysis conversion

Fenpyroximate is a systemic phenoxy pyrazole acaricide applied worldwide to prevent and control various phytophagous mites and has high activity against young mites, with residues increasingly being found in ecological environment and agricultural products. To identify its residues, four haptens of fenpyroximate were designed and an indirect competitive enzyme-linked immunosorbent assay (icELISA) based on monoclonal antibodies (2G4C7) was developed. Because the icELISA had higher sensitivity to the hydrolysate (Hapten A) of fenpyroximate, a method for indirectly determining the concentration of fenpyroximate was established by measuring the content of Hapten A. The assay had a working range of 0.07–1.49 ng/mL and a half-maximal inhibitory concentration (IC50) of 0.34 ng/mL. It showed average recoveries of 77.0%–105.4 %, 72.3%–106.4 % in citrus and apple samples, respectively. The icELISA and UPLC-MS/MS test results for samples of various citrus cultivars are remarkably consistent. These results and data represent the icELISA is suitable and applicable for detecting fenpyroximate residuals in fruit and vegetable samples.

A coumarin based ratiometric fluorescent probe for the detection of Cu2+ and mechanochromism as well as application in living cells and vegetables

In this paper, a novel coumarin-derived fluorescent probe NY was designed and synthesized. NY displayed a significant ratiometric fluorescence response towards Cu2+ in PBS buffer (10 mM, pH = 7.4), with the emission wavelength blue-shifted from 580 to 495 nm, and a fluorescence change from orange to green was evident under a 365 nm UV light. Meanwhile, NY had the advantages of high selectivity, short response time (5 min), low detection limit (1.3 × 10-8 M) and large binding constant (1.45 × 105 M-1) towards Cu2+. The binding mechanism between NY and Cu2+ was elucidated by FT-IR, 1H NMR titration, TOF-MS and Job's plot analysis. In addition, NY was successfully employed in the detection of Cu2+ within environmental water and vegetable samples with satisfactory results. Laser confocal microscopy imaging results showed that NY could easily penetrate HeLa cells membrane to target mitochondria and image Cu2+ in living cells. Furthermore, NY demonstrated mechanochromic properties by exhibiting orange-red fluorescence when subjected to mechanical grinding.

Dietary intake and trophic transfer of cadmium and lead from three daily consumption vegetables in Quito, Ecuador

The presence of toxic metals in vegetables of daily consumption is a concern for human health. Little is known about the concentration of toxic metals in vegetables sold in markets in Quito, Ecuador, and the corresponding risk to the population. This study aimed to measure the concentration of cadmium (Cd), and lead (Pb) in tomatoes, carrots, and lettuce, to estimate the risk for human health, and to determine the trophic transfer factor using Drosophila melanogaster flies. Vegetable samples were obtained from four local markets in Quito to measure the concentration of Cd and Pb (expressed in mg/kg of dry weight) in the vegetables by microwave-assisted acid digestion and atomic absorption spectrophotometry. Drosophila melanogaster flies were fed with contaminated vegetables to determine de trophic transfer factor of metals in the trophic chain. Our results showed the highest accumulation of Pb and Cd occurred in lettuce. In all cases, the Pb and Cd concentrations exceeded the maximum levels established by the Food and Agriculture Organization. However, the daily intake of metals and the health risk index showed no risk from daily consumption. Pb’s trophic transfer factor was excessively high in the tomato-fed flies, showing transference and accumulation in the flies. Cadmium concentration in tomato-fed flies was also the highest among the three vegetables. The trophic chain transfer of toxic metals from vegetables to Drosophila has been observed through a high accumulation of these metals in flies, and this suggests a negative impact on both human health and ecosystems.

Application of chemometric modeling for ionic liquid-based ultrasonic-assisted dispersive liquid-liquid microextraction: Analysis of fosetyl-aluminum in fruit and vegetable samples

This manuscript presents a new method for selective extraction and determination of fosetyl-aluminum in fruits and vegetable samples based on ultrasonic-assisted dispersive liquid-liquid microextraction method using ionic liquids (IL-UA-DLLME). A UV-Visible spectrophotometer was used for detection and quantification. Plants used for sample collection were grown under controlled conditions in a greenhouse. Central composite design (CCD)-response surface methodology (RSM) analysis was used for the optimization of significant factors (volume of IL, pH, ultrasonication time, and THF volume). Under optimal conditions, the limit of detection and limit of quantification of the IL-UA-DLLME procedure were 1.5 ng mL−1 and 5.0 ng mL−1 respectively with relative standard deviation 1.9–3.3%. The developed IL-UA-DLLME procedure demonstrated linearity within the concentration range of 5–600 ng mL−1 with an R2 value of 0.9914. The enrichment factor was 114 with a recovery% of 94.2–98.6% (n = 3) at optimal conditions. The IL-UA-DLLME assay was used for the analysis of fosetyl-aluminum in a variety of food samples and was found highly selective and efficient.

Simultaneous electrochemical determination of cadmium(II), lead(II), and mercury(II) ions in water and food samples using N1‐hydroxy‐N1,N2‐diphenylbenzamidine and multi‐walled carbon nanotubes modified carbon paste electrode

AbstractA novel modified carbon paste electrode has been developed using a laboratory synthesized metal chelating ligand (L), N1‐hydroxy‐N1,N2‐diphenylbenzamidine (HDPBA) and multi‐walled carbon nanotubes (MWCNTs) composite (L‐MWCNTs/CPE). The developed modified electrode was applied for selective and sensitive simultaneous electrochemical determination of cadmium(II), lead(II), and mercury(II) using square wave anodic stripping voltammetry (SWASV). The accumulation of metal ions on the electrode surface was performed in 0.1 M acetate buffer solution (ABS, pH 5.0) by applying a potential of–1.10 V versus Ag/AgCl for 210 s, followed by stripping in the positive potential scan of the SWASV after a rest time of 10 s. Under the optimum experimental conditions, the linear dynamic ranges were found to be 2×10−4–2, 1×10−4–2 and 2×10−3–2 μM of cadmium(II), lead(II), and mercury(II), respectively, with the detection limits (LODs) of 2.5×10−2, 7.8×10−3 and 4.6×10−1 nM for cadmium(II), lead(II), and mercury(II), respectively. The proposed electrode exhibited high sensitivity for the determination of these metal ions with excellent reproducibility and stability. The influence of several ions on the simultaneous determination of Cd(II), Pb(II), and Hg(II) was studied, and the prepared electrode was found to be highly selective for the detection of the three metal ions. The developed electrode was effectively applied to the determination of the three metal ions in water, vegetable and tobacco samples, and the obtained results were similar to those measured with graphite furnace atomic absorption spectrometry (GFAAS).

Optimization and evaluation of ultra-trace amounts of lead in real samples using sol–gel based optical sensor coupled with colorimetry

The entrapment of the sensitive reagent 5-(2′-bromophenylazo)-6‑hydroxy-pyrimidine-2,4‑dione (BPAHPD) in a silica sol-gel thin film coated on a glass substrate has been investigated for the development of a highly sensitive and selective optode for the determination of lead ions. The fabrication of thin films requires tetraethoxysilane as a precursor, a sol-gel pH of 2.75, a water: alkoxide ratio of 5:1, and a BPAHPD concentration of 4.0 × 10–4 M. The effect of sol-gel parameters on the optode's sensing performance was investigated. The fabricated optode is utilized for lead ion detection over a dynamic range of 4.00–144 ng mL–1 with detection and quantification limits of 1.20 and 3.95 ng mL–1, respectively. It gave repeatable results with relative standard deviation (RSD) values of 1.90% and 1.15% for lead concentrations of 40.0 and 80.0 ng mL–1, respectively, and a response time of two minutes. Through capturing BPAHPD in a sol-gel matrix and appropriately modifying the structure of doped sol-gel, interference studies have determined that lead exhibits a high degree of selectivity. To ascertain total lead, Pb4+ was reduced to Pb2+ using a few drops of 6.00 M hydrochloric acid and a freshly prepared sodium azide solution of 2.50 % (w/v). The optode can be easily regenerated with 0.15 M of nitric acid solution. The optode has complete reversibility. Optode detection of lead in diverse vegetable, food, biological, water, and soil samples yielded favorable results when compared to other techniques.

Molecular Detection and Prevalence of Toxoplasma gondii in Ready-to-eat Vegetables and Oysters in Central Luzon, Philippines

Toxoplasmosis, a parasitic infection caused by T. gondii, may be considered as a neglected disease in the Philippines. Consumption of raw or undercooked cyst-containing meat and accidental ingestion of oocysts excreted in the environment are two of the main routes in acquiring the infection. In the Philippines, there is no comprehensive or updated information on the prevalence of T. gondii among human populations and as a food-borne pathogen. We detected T. gondii DNA in ready-to-eat (RTE) vegetables and oysters sold in markets in Central Luzon, Philippines using molecular method. Six (10%) out of the 60 collected vegetable samples tested positive through nested PCR amplification of B1 gene. As for the oyster samples, four (9.09%) out of the 44 collected pooled samples were positive for T. gondii. Phylogenetic analyses revealed all the DNA sequences retrieved from positive samples clustered with T. gondii with a virulent Type 1 genotype (accession no: KX270388). Further studies should be done to identify the exact genotypic profiles of the T. gondii detected in the vegetable and oyster samples to infer pathogenicity and possible sources of contamination. Our findings suggest possible transmission patterns of T. gondii oocysts as a potential health threat to consumers.

Stability of Vitamin C Content in Plant and Vegetable Juices under Different Storing Conditions

The effect of environmental variables on vitamin C degradation in the analysed plant and vegetable juice samples was investigated. The study focused on samples from chives, dandelion, and nettle, as well as tomato, carrot, cucumber, red and white peppers, and cabbage. The aims of the study were to summarise the impact of storage time, temperature, and packaging materials on antioxidants (using vitamin C as an example) in processing plant and vegetable juices. The vitamin C concentration was tested iodometrically at 0 to 21 days intervals. Storage was carried out at different temperatures (4 °C, 23 °C, −18 °C) and in two selected packaging materials (glass and plastic). The analyses showed that low temperatures (t = 4 °C) and storage in glass containers are best for preserving vitamin C content. Storage time influenced the decrease in vitamin C values, with higher losses accompanying longer storage times. Plastic containers had a shorter shelf life for vitamin C compared to glass containers. In general, high temperatures during processing and storage have a negative effect on the preservation of vitamin C. Therefore, storing juices in the refrigerator and glass containers intended for food applications to minimise vitamin C degradation is important.

Detection and Prevalence of Soil Transmitted Helminths Contaminating Several Vegetables in Several Traditional Markets in Surabaya

A total of 100 fresh vegetable samples consisting of yardlong bean, cabbage, lettuce, and lemon basil were purchased from five traditional markets in Surabaya. Each sample was washed with tap water, water washing examined using flotation method to find soil-transmitted helminths. The overall prevalence of soil-transmitted helminths contamination was 41% (41/100). The most predominant parasite was hookworms (20%), followed by Strongyloides stercoralis larvae (14%) and Ascaris lumbricoides eggs (7%). The highest prevalence of contamination was found in lettuce, with a prevalence rate of 56% (14/25), while the lowest prevalence of contamination was found in yardlong bean, with a prevalence rate of 24% (6/25). Sequentially, the prevalence of soil-transmitted helminths contamination of fresh vegetable samples from Pabean traditional market (55%), Keputran traditional market (50%), Wonokromo traditional market (50%), Lakarsantri traditional market (35%) and Mulyosari traditional market (15%), respectively. The present study demonstrated that consumption of vegetables with parasite contamination in this area represents a potential route for the transmission of soil-transmitted helminths infection.

Initial research on the application of the liquid chromatography - quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) method for monitoring pesticide residues in fruits and vegetables

Currently, there are thousands of plant protection chemicals being allowed for use in agriculture. Abuse or improper use of pesticides lead to increase residues in products, exceeding the maximum residue limit according to the regulations. Therefore, the need for developing methods, which can monitor, detect, and identify many pesticides simultaneously is necessary. The liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS) method has advantage of being able to simultaneously quantify and screen many compounds at once, are being a trend in analytical techniques for analyzing and screening pesticide residues in foods. In this study, the LC-QTOF-MS method was used to quantify 186 pesticides in fruit and vegetable samples. The limit of detection (LOD) for all compounds is 3.0 µg/kg. The recovery is in the ranged of 74.4 -118%, relative standard deviation (RSD) <20%. At the same time, the method was initial researched for nontarget screening by reprocessing previously acquired data without re-injection of the samples. The list of pesticides can be screening, which are up to 500 chemicals, by comparison results with the available high resolution mass spectral library. The screening detection limit of the method (SDL) is 100 µg/kg. The method has been applied to quantify 186 pesticides, and nontarget screening analyse in 160 fruit and vegetable samples in the first 06 months of 2023.

Suspect screening of pesticide co-formulants in fruits, vegetables and leaves by liquid and gas chromatography coupled to high resolution mass accuracy spectrometry: Potential impact on human health

Vegetables can contain co-formulants derived from the use of plant protection products (PPPs) in crops. Thus, in the current study co-formulants were determined in different fruits and vegetables and their leaves by gas and liquid chromatography coupled to Q-Orbitrap high-resolution mass spectrometry (GC-Q-Orbitrap and LC-Q-Orbitrap-MS). A total of 37 co-formulants were tentatively identified, and among them, 12 compounds were quantified by LC-Q-Orbitrap-MS and 9 by GC-Q-Orbitrap-MS. The mean co-formulant levels in fruit and vegetable samples was 92% lower than in leaf samples. Selected samples showed a high concentration of 1-ethyl-2-pyrrolidone among the co-formulants detected. This compound ranged from 22 µg/kg (strawberry) to 722 µg/kg (red grape), whereas in the case of leaves, its concentration was up to 6513 µg/kg in cucumber leaf. In addition, it has an LD50 equal to 1.440 g/kg. Therefore, this type of PPP co-formulants should be controlled in fruits and vegetables to avoid adverse health effects.

Detection of hemolytic Shiga toxin-producing Escherichia coli in fresh vegetables and efficiency of phytogenically synthesized silver nanoparticles by Syzygium aromaticum extract and gamma radiation against isolated pathogens

BackgroundShiga toxin-producing E. coli (STEC) is a major cause of foodborne diseases accompanied by several clinical illnesses in humans. This research aimed to isolate, identify, and combat STEC using novel alternative treatments, researchers have lately investigated using plant extract to produce nanoparticles in an environmentally acceptable way. At various gamma-ray doses, gamma irradiation is used to optimize the conditions for the biogenically synthesized silver nanoparticles (Ag NPs) using an aqueous extract of clove as a reducing and stabilizing agent.MethodsOn a specific medium, 120 vegetable samples were screened to isolate STEC and molecularly identified using real-time PCR. Moreover, the antibacterial and antibiofilm activities of biogenically synthesized Ag NPs against the isolated STEC were examined.ResultsTwenty-five out of 120 samples of eight types of fresh vegetables tested positive for E. coli, as confirmed by 16S rRNA, of which three were positive for the presence of Stx-coding genes, and six were partially hemolytic. Seven antibiotic disks were used to determine antibiotic susceptibility; the results indicated that isolate STX2EC had the highest antibiotic resistance. The results demonstrated that Ag NPs were highly effective against the STEC isolates, particularly the isolate with the highest drug resistance, with inhibition zones recorded as 19 mm for STX2EC, 11 mm for STX1EC1, and 10 mm for STX1EC2 at a concentration of 108 µg/mL. MICs of the isolates STX1EC1, and STX1EC2 were 13.5 µg/mL whereas it was detected as 6.75 µg/mL for STX2EC. The percentages of biofilm inhibition for STX1EC2, STX1EC1, and STX2EC, were 78.7%, 76.9%, and 71.19%, respectively.ConclusionThese findings suggest that the biogenic Ag NPs can be utilized as a new promising antibacterial agent to combat biofouling on surfaces.

Essential role of multi-element data in interpreting elevated element concentrations in areas impacted by both natural and anthropogenic influences.

This article presents a detailed analysis of a dataset consisting of 27 elements found in soils, soil eluates, and vegetables from private gardens in a region with a long history of coal mining and burning. With coal being one of the world's most significant energy sources, and previous studies highlighting elevated element levels in vegetables from this region, the objective of this study was to identify the factors that impact soil geochemistry and metal(loid) uptake in plants. Total major and trace element concentrations were analyzed in soils, soil eluates and vegetables by high resolution inductively coupled plasma mass spectrometry. The vegetable samples included six species: fennel, garlic, lettuce, parsley, onion, and radicchio. Each plant was divided into roots, stems, leaves, and/or bulbs and analyzed separately. In addition, the soil pollution status, bioavailable fractions and transfer factors from soil and soil eluates to different plant parts were determined. The comprehensive dataset revealed that, apart from the substrate enriched with various elements (Al, As, Co, Cr, Mo, Ni, Pb, Sb, Sn, Ti, U, V, and Zn), other anthropogenic factors such as the legacy of coal mining and combustion activities, associated industries in the area, transport, and agricultural practices, also influence the elevated element concentrations (Cd, Cu, Fe, Mn, and Se) in locally grown vegetables. The transfer factors based on element concentrations in aqueous soil eluates and element bioavailable fractions confirmed to be an effective tool for evaluating metal uptake in plants, emphazising to some extent the effects of plant species and revealing unique patterns for each pollution source within its environmental context (e.g., Cd, Mo, S, and Se in this case). The study highlights the crucial importance of utilizing comprehensive datasets that encompass a multitude of factors when interpreting the impacts of element uptake in edible plants.

Non-enzyme picomolar sensing of acephate by modified glassy carbon electrode using bimetallic Zn-Cu metal-organic framework

Organophosphate pesticides are used ubiquitously in agriculture; however, their excessive use can cause problems for human health and the environment. Herein, a non-enzymatic electrochemical sensor has been designed and developed for sensing acephate, which is based on modifying a glassy carbon electrode (GCE) with a zinc-copper metal–organic framework (Zn-Cu MOF) as a sensing material and activated charcoal (AC) as an additive for enhancing conductivity and charge transfer rate. Bimetallic Zn-Cu MOF was synthesized using the one-pot solvothermal method and was characterized by different analytical techniques, viz., Field Emission scanning microscope (FE-SEM), High-Resolution Transmission Electron Microscopy (HR-TEM), X-ray Photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Raman spectroscopy, and Fourier-transform infrared (FTIR) spectroscopy. The electro-catalytic behavior of the modified GCE was studied using Cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS), and Differential pulse voltammetry (DPV), which shows better performance as compared to the bare electrode. The modified GCE demonstrates excellent electro-catalytic activity towards acephate molecules, which may be attributed to the synergistic effect of metal ions, high porosity, enhanced active sites, superior conductivity, higher specific surface area, and faster electron transfer rate. After optimization of parameters such as electrolyte pH and volume of coating on GCE, the Zn-Cu MOF/AC/GCE-based electrochemical sensor provides excellent performance in terms of a more comprehensive linear range from 0.1 to 10 nM, the limit of detection (LOD) of 3.3 pM (S/N = 3), excellent selectivity and reproducibility. The extract of vegetable samples spiked with acephate gave satisfactory recovery results in 95.2–103% for tomato juice and 97–107% for cucumber juice.

DETERMINATION OF TRITIUM IN VEGETATION IN THE OBSERVATION AREA OF REACTOR WWR-K IN KAZAKHSTAN

In assessing the impact of radiation-hazardous facilities on the environment and humans, considerable attention is currently paid to the problem of tritium and its compounds intake. It is important to note that to date there are no effective industrial technologies for efficient capture of this radionuclide. As a result, all the tritium produced during the operation of nuclear power plants with emissions and discharges is released into the environment. This leads to increased tritium concentrations in the environment, including vegetation. The aim of this work is to develop and adapt a set of methods for sample preparation and determination of tritium in vegetation samples. Methodology: A special Carbolite Gero MTT tube furnace was used to improve sample preparation methods and maximise the recovery of organically bound tritium from vegetation. Tritium was measured by liquid scintillation beta spectrometry. Results and Discussion: This research paper presents the results of the study and implementation of the method of tritium determination in vegetation near the VVR-K reactor located in the city of Almaty, Kazakhstan. Conclusions: The developed method of tritium determination in vegetation can be applied for radiation monitoring of tritium content and its compounds in the vicinity of nuclear industrial facilities. The presented data emphasise the need for systematic studies of tritium accumulation in environmental components. It is expected that in the future, using the implemented method, the studied area will be studied in detail, taking into account an extended set of factors: meteorological conditions, reactor operation mode and others. Thus, for a more complete and reliable assessment of tritium radionuclide activity determination, it is necessary to carry out works to determine the type of vegetation accumulating this isotope.

Non-carcinogenic and carcinogenic health risk assessment of heavy metals in cooked beans and vegetables in Punjab, North India.

Beans and vegetables are consumed with cereals in India on daily basis. The aim of the study was to assess carcinogenic and non-carcinogenic risk of heavy metals in cooked beans and cooked vegetables consumed by adults (18-59 years) and elderly (≥60 years) subjects from two districts (Ludhiana and Bathinda) of Punjab. A total of 150 households were selected from 30 different locations covering both rural and urban areas. The mean daily consumption of beans and vegetables in Ludhiana was recorded as 35.09 and 215.93 g, respectively. The corresponding figures in Bathinda were observed as 26.85 and 230.54 g. The average amounts of arsenic, cadmium, lead, and mercury were 1.44 × 10-5, 8.21 × 10-5, 1.30 × 10-3, and 2.61 × 10-7 mg/kg for cooked vegetables in urban households of Ludhiana district, respectively. The corresponding values for rural households were 1.53 × 10-5, 5.58 × 10-5, and 2.98 × 10-4 mg/kg while mercury was not detected. The mean chronic daily intake (CDI) of arsenic from cooked beans was significantly (p ≤ .001) higher in urban adult males of Ludhiana (7.74 × 10-9 mg/kg/day) and Bathinda (5.31 × 10-9 mg/kg/day) compared to their rural counterparts. Similar trend was observed in CDI of heavy metals from vegetables. The mean CDI of cadmium from cooked vegetables in urban adult females of Ludhiana (3.76 × 10-7 mg/kg/day) was significantly (p ≤ .001) higher than their rural counterparts and both urban and rural adult females of Bathinda. The study concluded that the subjects of both districts were found safe from non-carcinogenic and carcinogenic risk associated with heavy metals present in cooked beans and vegetables, except for urban subjects and rural adult subjects of Ludhiana district who had cancer risk due to cadmium present in cooked vegetable samples.

Bacterial Examination in Spoiled Vegetables, Its Isolation, Identification and Antibacterial Activity of Turmeric, Pongamia and Betel Leaf

Microbial contamination is a major concern in the food and pharmaceutical industries, leading to economic losses and public health risks. Natural products such as turmeric, betel leaf, and Pongamia leaves have been traditionally used for their antimicrobial properties. This thesis aimed to examine, identify, and isolate bacteria from selected spoiled vegetable samples and to evaluate the antibacterial activity of turmeric, betel leaf and Pongamia leaves. Bacterial isolation was performed using standard microbiological techniques, and the identification was done based on cultural characteristics. The antibacterial activity was assessed using disc diffusion method. The results showed the presence of bacterial contaminants in the tested samples, including Staphylococcus sp. And Escherichia coli. The turmeric, betel leaf, and Pongamia leaves extracts exhibited significant antibacterial activity against the tested bacteria. The phytochemical analysis of the extracts revealed the presence of alkaloids, flavonoids, phenols, tannins, and saponins, which may contribute to their antibacterial properties. This research provides valuable insights into the microbial contamination of food and pharmaceutical samples and the potential of natural products as antimicrobial agents. The findings of this study can contribute to the development of new antimicrobial agents based on natural products and the improvement of food and pharmaceutical safety.

Furan-formulated benzothiazole based Schiff bases for highly selective visual and fluorometric detection of Cu2+ ion with density functional theory studies and its application for real-life samples

In this work, we describe the synthesis of a Schiff base (R1) derived from furfural and 2-hydrazinobenzothiazole which displayed turn-off selective fluorescent chemo-sensing properties for Cu2+ ions in THF: HEPES buffer (9:1, v/v) solution. The molecular structure of the Schiff base (R1) was characterized by various spectroscopic techniques such as FTIR, 1H NMR, 13C NMR, and HRMS. Interestingly, R1 upon interaction with various metal cations displays highly selective colorimetric and fluorescent turn-off response to Cu2+ ions. The UV–Vis absorption study of the R1 with Cu2+ ions exhibits a noticeable color change from yellow to brown color with a redshift (∼60 nm). Upon the addition of Cu2+ ions emission quenching at 529 nm was observed in R1, and the limit of detection (LOD) and limit of quantification (LOQ) were found to be 3.23 × 10−9 M and 10.79 × 10−9 M. The mechanisms of probe R1 for sensing Cu2+ ions have been well demonstrated by Job's plot, Benesi-Hildebrand studies, and Density functional theory calculations (DFT). Owing to practical application, the Cu2+ ions were efficiently determined using a spike and recovery approach from real water and vegetable extract samples. Further, the developed R1 sensors were used for test strips application to detect the Cu2+ ions and achieved naked-eye detection. Therefore, these investigated results demonstrate that sensor R1 has great potential to detect Cu2+ ions in environmental analysis systems.

Determination of primary and secondary oxidation products in vegetable oils with gold nanoparticle based fluorometric turn-on nanosensor: A new total oxidation value

Oxidation of fats and oils gives rise to lipid hydroperoxides as primary oxidation products (POPs) and carbonyl compounds as secondary oxidation products (SOPs). Here, we report the sensitive detection of POPs and SOPs (oxidation products) involving direct and indirect redox reactions with iodide ions, respectively, using the fluorophore probe (fluorescein-5-isothiocyanate-gold nanoparticles; FITC-AuNPs). Iodide released the fluorescent FITC from FITC-AuNPs in the turn-on mode. In case of SOPs, an indirect iodide determination was made through the use of chloramine-T as carbonyl reagent. To various vegetable oil samples, deep frying process (at 160 °C, simulating frying conditions) and soft oil oxidation (at 100 °C, simulating cooking conditions) were carried out for a period of time (1, 5 and 10 days). Total content of POPs varied between 4.00 and 5.70 g TBHP (t-butylhydroperoxide)/kg oil, and the amount of SOPs was found as 1.12–4.11 g t-2-nonenal/kg oil in non-oxidized oil samples. The proposed method was validated against FOX and p-anisidine value (p-AV) assays. Sensory analyses (taste, color, smell and appearance) results of non-oxidized and deep-fried oil samples were consistent with those of the proposed FITC-AuNP nanosensor. Finally, a new total oxidation (TOD) value (expressed as iodide equivalent meq/kg oil) was proposed to determine the overall oxidation state and quality of the oils. Our proposed TOD value is not only mathematically precise with respect to its units (i.e. POPs and SOPs are added up in the same equivalent units to obtain TOD) but also is in better accordance with the results of sensory analysis.

Heavy metal contamination and health risk assessment of horticultural crops in two sub-cities of Addis Ababa, Ethiopia

This particular study was aimed to establish the level of heavy metals in different horticultural crops cultivated by irrigation and the soil in two sub-cities of Addis Ababa, Ethiopia, and quantitatively assess the health treat they pose for the consumer. A total of 151 vegetable samples comprised of lettuce (Lactuca sativa), cabbage (Brassica oleracea var. capitate), cucumber (Cucumis sativus), potato (Solanum tuberosum), parsley (Petroselinum crispum), Swiss chard (Beta vulgaris subsp. vulgaris), beetroot (Beta vulgaris), green onion (Allium porrum L.) and 28 soil samples were collected for this study. Six toxic elements were analyzed using microwave plasma atomic emission spectroscopy (MP-AES) after microwave assisted digestion of the samples. The concentrations of examined trace elements in vegetables (mg/kg) were found in the range of 5.50–93.00 for zinc; below detection limit (BDL)− 18.50 for copper; BDL-2.50 for nickel; BDL-17.00 for lead; 5.00–4256.50 for manganese and 22.00–8708.00 for iron. Considering the mean Pb content values, all vegetables exceeded the maximum permissible level set by the joint FAO/WHO commission in both irrigation sites. In case of Mn parsley, swiss chard, and green onion all from site two exceeded the maximum allowable values. With the exception of potato from irrigation site one, all vegetables exceeded the maximum permissible limit set for Fe concentration and out of which parsley, swiss chard, and green onion, all from site two, exceeded by more than double amount. The same trend is observed for the concentration of Mn and Fe in the soil samples. In fact, in both irrigation sites their concentration exceeded the allowable limits set by United Nation Environment Program (UNEP) for agricultural soils. The metal pollution load index revealed that in most of the vegetables studied the overall pollution load of trace metals were higher in Kolfe Keranyo irrigation site. The risk assessment study using indices like estimation of daily/weekly dietary exposure, hazard quotient and metal pollution load index all suggested consumption of the studied vegetables poses a significant health risk for the consumer. For adults the calculated target hazard quotient for the trace element Pb is higher than 1 (one) for all of studied vegetables ranging from 11.086 (cucumber) to 17.881 (beetroot) with a 98.216% and 98.464% contribution to the hazard indices, respectively. For a child consumer, Mn showed a higher target hazard quotient vales ranged from 0.0107 (cucumber) to 0.0495 (green onion) with a 70.86% and 88.85% contribution to the total hazard indices, respectively. The soil pollution indices also indicated that the degree of metal enrichment in soils and sediments are higher than the allowable limits. Therefore, a prompt action is required to curb the problem and ensure the public safety along the food system line.