Vegetable Samples Research Articles

An aptasensor with colorimetric and electrochemical dual-outputs for malathion detection utilizing peroxidase-like activity of Fe-MOF

An aptasensor with dual-outputs was developed for malathion detection. Fe-MOF was synthesized to design favorable signal probes for catalytic amplification. Owing to the excellent peroxidase-like activity of Fe-MOF, the redox reaction was catalyzed to produce the dual-outputs of colorimetric and electrochemical. In this sensing strategy, malathion was captured by the aptamer on sensing interface, leading to the release of signal probe. Thanks to the catalytic amplification of Fe-MOF and the high capture effect of aptamer, the aptasensor produced a sensitive response for malathion. Based on the dual-signals of absorbance and current, the detection method for malathion was developed ranging from 10 ng/mL to 500 ng/mL. The detection limit of malathion was 5.8 ng/mL for colorimetric output and 4.6 ng/mL for electrochemical output. Furthermore, the aptasensor exhibited high specificity and good repeatability in malathion detection. Finally, the aptasensor was applied to detect malathion in fruit and vegetable samples with satisfactory recovery.

Diversity of Mycotoxin-Producing Fungi in Leafy and Fruit Vegetables Sold in Port Harcourt Metropolis, Nigeria

Mycotoxins are secondary metabolites produced by fungi and are capable of causing diseases and even death in both humans and other animals. This study investigated the diversity of mycotoxin-producing fungi from leafy (Telfairia occidentalis and Bassica oleracea) and fruit (Solanum lycopersicum and Cucumis sativus) vegetables sold in Port Harcourt metropolis, Nigeria using molecular techniques. The fungi were isolated from vegetable samples showing signs of disease using standard methods. DNA extraction and Polymerase chain reaction were carried out at the molecular laboratory of Regional Centre of Biotechnology and Bioresources research, University of Port Harcourt. The isolates were screened for the presence of mycotoxigenic genes (nor1 (aflatoxin), tri6 (trichothecene), otanps (Ochratoxin A), fum13 (fumonisin) and ZEA (zearalenone)) using PCR technique. The isolates containing mycotoxins were identified using ITS gene sequences. Ten out of the eighteen isolates were positive for four (nor1, tri6, otanps and fum13) out of the five mycotoxigenic genes screened. The nine isolates included fungi belong to six genera: Meyerozyma, Pithomyces, Fusarium, Trametes, Penicillium and Aspergillus. The ten isolates were classified as Meyerozyma carbbica RCBBR_Sf13, Pithomyces chartarum RCBBR_Sf5, Fusarium falciforme RCBBR_Sf10, Trametes duplexa RCBBR_Sf17, Trametes versicolor RCBBR_Sf2a, Trametes duplexa RCBBR_Mf1, Fusarium longifundum RCBBR_Mf4, Penicillium soosanum RCBBR_Mf7, Aspergillus aflatoxiformans RCBBR_Sf9, Fusarium circinatum RCBBR_Sf3 based on their ITS gene sequences. Their ITS gene sequences have been deposited in GenBank under the accession numbers OR816039-OR816047, with the exception of Fusarium circinatum RCBBR_Sf3 which could not accession. This study has demonstrated that mycotoxin-producing fungi are diverse and widespread in leafy and fruit vegetables sold within Port Harcourt Metropolis. This raises both public health and food security concerns.

Elastin-like polypeptide-functionalized nanobody for column-free immunoaffinity purification of aflatoxin B1.

A column-free immunoaffinity purification (CFIP) technique for sample preparation of aflatoxin B1 (AFB1) was developed using an AFB1-specific nanobody (named G8) and an elastin-like polypeptide (ELP). The reversible phase transition between liquid and solid in response to temperature changes was exhibited by the ELP which was derived from human elastin. The G8 was tagged with ELPs of various lengths (20, 40, 60, and 80 repeat units) at the C-terminus using recursive directional ligation (RDL). Coding sequences were then subcloned into pET30a at the multiple cloning sites. Bioactive recombinant proteins were produced by expressing them as inclusion bodies in Escherichia coli BL21 (DE3), then dissolved and refolded. Analysis by indirect competitive enzyme-linked immunosorbent assay (icELISA) and transition temperature (Tt) measurement confirmed that the refolded G8-ELPs preserved the ability to recognize AFB1 as well as phase transition when the temperature rose above Tt. To establish the optimal conditions for cleaning AFB1, the effects of various parameters on recovery were investigated. The recovery in ELISA tests was 95 ± 3.67% under the optimized CFIP workflow. Furthermore, the CFIP-prepared samples were applied for high-performance liquid chromatography (HPLC) detection. The recovery in the CFIP-HPLC test ranged from 54 ± 1.86% to 98 ± 3.58% for maize, rice, soy sauce, and vegetable oil samples. To the best of our knowledge, this is the first report combining the function of both nanobody and ELP to develop a cleanup technique for small molecules in a complex matrix. The CFIP for the sample pretreatment was easy to use and inexpensive. In contrast to conventional immunosensitivity materials, the reagent utilized in the CFIP was entirely biosynthesized without any chemical coupling reactions. This suggests that the nanobody-ELP may serve as a useful dual-functional reagent for the development of sample cleaning or purification methods.

β-Cyclodextrin based magnetic hyper-crosslinked polymer: A recyclable adsorbent for effective preconcentration of triazine herbicides in complex sample matrices

High efficiency enrichment and trace analysis of triazine herbicide residues are crucial for ensuring environmental and food safety. Herein, a series of magnetic hyper-crosslinked polymers (CD-gs-MHCPs) were synthesized with different crosslinkers, which might possess different pore structure and surface area, so they might dispay variable adsorption performance. CD-gs-MHCP2 with dichloroxylene as crosslinker delivered superior adsorption ability for triazine herbicides (THs). The synergistic effect of hydrogen bonds, hydrophobic interaction, π-π stacking interaction and pore adsorption were proved to be the main adsorption mechanism. Combined CD-gs-MHCP2 based magnetic solid-phase extraction (MSPE) with high-performance liquid chromatography, the quantitative analysis of THs in river water and vegetable samples (zucchini, pakchoi) was achieved. Under the optimal conditions, the enrichment factors for three different samples ranged from 94 to 244 and low detection limit (S/N = 3) of the four THs were obtained from 0.05 to 0.15 ng mL−1 for river water and 0.31–3.10 ng g−1 for vegetable samples. The method recoveries were in the range of 86.2 %–120 % with relative standard deviations lower than 7.4 %. This work not only offers a new strategy for fabrication β-CD-based HCPs, but also provided a practical and effective method for efficient isolation and sensitive detection of trace THs residues in complex samples.

Exploring the role of canopy cover and environmental factors in shaping carbon storage in Desa’a forest, Ethiopia

BackgroundDry Afromontane forests play a vital role in mitigating climate change by sequestering and storing carbon, as well as reducing greenhouse gas emissions. Despite previous research highlighting the importance of carbon stocks in these ecosystems, the influence of canopy cover and environmental factors on carbon storage in dry Afromontane forests has been barely assessed. This study addresses this knowledge gap by investigating the effects of environmental factors and vegetation cover on carbon stocks in Desa’a forest, a unique and threatened Afromontane dry forest ecosystem in northern Ethiopia. Data on woody vegetation, dead litter, grass biomass, and soil samples were collected from 57 plots. A one-way analysis of variance (ANOVA) was performed at a 95% confidence level (α = 0.05) to examine the influence of canopy cover and environmental factors on the carbon stocks of various pools.ResultsAmong the 35 woody species identified, Juniperus procera was the most dominant, while Carissa edulis Vahl and Eucalyptus globulus were the least dominant. The average total carbon stock was 92.89 Mg ha−1, with contributions from aboveground carbon, below-ground carbon, litter carbon, grass carbon, and soil organic carbon. Among the carbon pools, soil organic carbon had the highest carbon stock, accounting for 76.8% of the total, followed by above-ground biomass carbon at 17.7%. Significant variations in carbon stocks were found across altitude class and canopy level but not slope and aspect factors.ConclusionsIn summary, altitude and canopy level were found to significantly influence carbon stocks in Desa’a forest, providing valuable insights for conservation and climate change mitigation efforts in dry Afromontane forests. Forest intervention planning and management strategies should consider the influence of different environmental variables and tree canopy levels.

Physicochemical, Nutritional, and Antioxidant Properties of Traditionally Fermented Thai Vegetables: A Promising Functional Plant-Based Food.

Fermented plant-based products were gathered from various regions in Thailand and categorized into 10 types of traditional commercial vegetables. Different vegetable materials and natural fermentation methods influence the diverse physical, chemical, nutritional, and functional attributes of the products. All the traditionally fermented Thai vegetable samples collected showed physicochemical properties associated with the fermentation process, contributing to the nutritional and functional quality of the final products. Achieving consistent research results is challenging due to the intricate nature of food matrices and biochemical processes during fermentation. The roles of microorganisms, especially probiotics, are crucial in delivering health benefits through fermented foods. Traditionally fermented Thai vegetable foods contain high levels of total soluble solids, titratable acidity, and salinity in pickled shallot and ginger as a result of the natural fermentation process and the ingredients used. The research findings were confirmed using a hierarchical cluster analysis (HCA)-derived dendrogram pattern. The nutritional compositions, total phenolic contents, and antioxidant activities varied among the different types of vegetables. The correlations among lipid, protein, fiber, total soluble solid (TSSs), total titratable acidity (TTA), and salinity as potential biomarkers in fermented vegetable products were examined. The results suggest that traditionally fermented Thai vegetable products significantly impacted food research by enhancing the quality and preserving the authenticity of traditionally fermented Thai vegetables.

Assessment of potential toxic elements in soils, sediments, and vegetation in the surroundings of Anapa, Russia.

The study presented here reports the concentration of major, trace, and rare earth elements in soil, sediments, and vegetation samples collected from 13 locations around Anapa City located on the northern coast of the Black Sea in Russia. The neutron activation analysis technique has been used to fulfill this objective. Along with this, the bioconcentration and translocation factors were calculated. Overall, the content of 31 elements was detected in soil and sediments while 20 elements were determined in three types of vegetation: macroalgae (Cystoseira sp. and Ulva sp.), aquatic plants (Phragmites australis), and sea grass (Zostera sp.). The quantified concentration followed the order soil > sediment > vegetation. The phytotoxic levels for Zn, V, Mn, and Fe have been quantified as the highest. Bromine was the most abundant and accumulated in Phragmites australis. Based on the results obtained from this investigation, there is a possibility of contamination in the study area.

Resin bound gold nanocomposites assisted SE/ATR-FTIR spectroscopy for detection of pymetrozine insecticide in vegetable samples

The goal of this work was to assess the competence of organic hydrophobic resin bound gold nanocomposites (OH/R-AuNCs) for detection of pymetrozine insecticide from vegetable samples employing surface-enhanced/attenuated total reflectance-Fourier transform infrared (SE/ATR-FTIR) spectroscopy. The adsorption isotherm models, including the Langmuir, Freundlich and Temkin, are tested to reveal the interactive behaviour between the OH/R-AuNCs and pesticide. The adsorption occurs principally by London–Van der Waals dispersion interactions and hydrogen bonding interactions between the surface of OH/R-AuNCs materials and the hydrophobic part of pesticide molecule. The characteristic absorption band obtained at 3019.94 cm−1 was utilized for the quantitative analysis of pymetrozine insecticide in vegetable samples. The method was found to be accurate and precise, with mean recovery values in the range of 94.5–110 %, correlation coefficient of 0.992 %, and detection limit of 2.65 μg mL−1. The adsorption efficiency of the designed OH/R-AuNCs significantly influences the SE/ATR-FTIR response of the pymetrozine around 90 %. The optimized and validated method was applied to determine the residual concentrations of the pymetrozine that had been applied to vegetable samples.

Evidence for Wildland Fire Smoke Transport of Microbes From Terrestrial Sources to the Atmosphere and Back

AbstractSmoke from wildland fires contains more diverse, viable microbes than typical ambient air, yet little is known about the sources and sinks of smoke‐borne microorganisms. Data from molecular‐based surveys suggest that smoke‐borne microorganisms originate from material associated with the vegetation and underlying soils that becomes aerosolized during combustion, however, the sources of microbes in smoke have not yet been experimentally assessed. To elucidate this link, we studied high‐intensity forest fires in the Fishlake National Forest, Utah, USA and applied source‐sink modeling to assemblages of 16S ribosomal RNA (rRNA) gene sequences recovered from samples of smoke, vegetation, and soil. Our results suggest that 70% of the bacterial taxa in smoke originated from the local aspen (Populus tremuloides) (33%) and soil (37%) communities. In comparison, 42% of bacteria in air sampled prior to the fires could be attributed to these terrestrial sources. When the bacterial assemblages in smoke were modeled as sources to the local communities, they contributed an average of 25% to the terrestrial sinks versus an estimated contribution of <4% from ambient air. Our results provide support for the role of wildland fire in bacterial dispersal and the working hypothesis that smoke is an environmental reservoir of microbes for receiving ecosystems.

Succession in abandoned fields: Chronosequence data verified by monitoring of semi‐permanent plots

AbstractQuestionsIs there a similarity between successional patterns in abandoned fields identified (a) through analysis of differently aged sites examined at one point in time (chronosequence) and (b) those derived from a limited set of semi‐permanent plots? What is the rate of succession on dry and mesic abandoned fields and how is the participation of different functional groups changing during succession?LocationBohemian Karst, the Czech Republic, Europe.MethodsThis study utilises data collected from dry and mesic abandoned fields between 1975 and 2019. A data set of 129 chronosequence vegetation samples (54 dry and 75 mesic plots) and 26 samples from six semi‐permanent plots (11 dry and 15 mesic) with different repetitions were analysed. Plot age (since abandonment) varied from 1 to 91 years for chronosequences and up to 99 years for semi‐permanent data. Moreover, we compared the rate of succession between dry and mesic series using Bray–Curtis dissimilarity. We used a generalised linear mixed model to study the relationship between the cover of different functional groups and the age of abandoned fields.ResultsThe successional patterns observed on abandoned fields were consistent between the chronosequence and semi‐permanent plots. Both on dry and mesic fields, the early stages of succession transitioned from open annual to perennial herbal vegetation. In mesic fields, the succession led to woodland stands within approximately 25–30 years. Conversely, succession slowed down in dry fields and has persisted for several decades in a stage dominated mostly by perennial graminoids accompanied by scattered shrubs and trees. The trends detected with the chronosequence approach for the different functional groups corresponded to those found in semi‐permanent dry and mesic series plots.ConclusionsThe plots using a chronosequence approach can reliably reveal general successional patterns comparable to those obtained from semi‐permanent plots. Observing a higher number of plots at one time may better illustrate the variability of succession at the landscape scale than a detailed, long‐lasting study of a low number of semi‐permanent plots. In the studied area, the dry abandoned fields host a long‐persisting non‐forest state of succession under the current climatic conditions, while succession in mesic abandoned fields continues further towards woodland.

Five decades' experience of long‐term soil monitoring, and key design principles, to assist the EU soil health mission

AbstractThe European Union has a long‐term objective to achieve healthy soils by 2050. The European Commission has proposed a Directive of the European Parliament and of the Council on Soil Monitoring and Resilience (Soil Monitoring Law, SML), the first stage of which is to focus on setting up a soil monitoring framework and assessing soils throughout the EU. Situated in NW Europe, the UK has substantial experience in soil monitoring over the last half century which may usefully contribute to this wider EU effort. A set of overarching principles have and continue to guide design of national soil monitoring and may prove helpful as other European countries embark on similar monitoring programmes. Therefore, we present the principles of design from five decades of national soil monitoring. The monitoring discussed is based on a stratified‐random design, has matured in support of policy questions, and operates over space and time scales relevant to the SML. The UK Centre for Ecology & Hydrology (UKCEH) Countryside Surveys (CS) of Great Britain and Northern Ireland, Welsh Government, Environment and Rural Affairs Monitoring and Modelling Programme (ERAMMP) and the England Ecosystem Survey (EES) monitoring programme are national programmes currently operating in the UK. Some important lessons learnt include: adopting a question‐based approach; having a clear robust statistical design for the purpose; selecting indicators that address policy and underlying scientific questions; and selecting indicators that can detect change and use robust and well‐tested methodologies across a wide range of soil and land use types, remaining valid over long time scales, supporting thinking long‐term. Technical lessons learned include the proven cost effectiveness of a stratified‐random design including replication, while adopting a common stratification layer of stable environmental attributes aids comparability between monitoring programmes. Common protocols are vital for future intercomparisons, but a full ecosystem approach that includes co‐located soil and vegetation samples for interpreting a co‐evolving system has proved hugely advantageous. UK monitoring programmes offer a range of experience that may prove valuable to future soil monitoring design to address the major societal challenges of our time, such as maintaining food production and addressing climate change and biodiversity loss.

Safe and Healthy Food Preservation: Efficacy of Guava Leaves and Lemon Juice Extract on Fruits and Vegetables

Background: Fruits and vegetables are naturally perishable and have a relatively limited shelf life. This study was designed to prolong the shelf life and remain nutritional value of various fruits and vegetables by using guava leaves extract and lemon juice extract (natural preservatives). Methods: Fruits and vegetables samples (amla, banana, grapes, bean, eggplant and tomato) were treated with three types of natural preservatives: guava leaves and lemon juice extract (GLE) 0.5% (boiled), lemon extract (LE) 15%, GLE 40% + LE 15%. Results: The study revealed that the moisture content varied from 18.03% to 95.41%. During the 10 days of experiment, samples treated with 0.5% GLE (boiled) preservatives exhibited better result than other two types of preservatives regarding the moisture content. Titratable acidity content varied from 0.05% to 2.25%. The pH value varied in the range of 2.47-6.01. The percentage of weight loss value ranged from 3.67 to 85.71. During the experiment period, weight loss was minimum almost in all samples treated with GLE 40%+LE 15% preservative. The vitamin C content in fruits and vegetables ranged from 1.60 mg/100mL to 68.46mg/100mL. The highest viable count was found in banana (46×104 CFU/ml) and the lowest was in Bean (9×104 CFU/ml). Conclusion: Among three types of preservatives, samples treated with 0.5% GLE (boiled) showed better result and minimum microbial growth.

Molecular detection and antibiogram profiles of Escherichia coli and Vibrio cholerae isolated from raw vegetables in the northern district of Bangladesh

Raw vegetables are essential for a well-balanced diet as they provide vitamins, minerals, dietary fiber, and phytochemicals. This study aimed to isolate, identify, and evaluate the microbial loads of Escherichia coli and Vibrio cholerae in raw vegetables sold at local markets in the Dinajpur district of Bangladesh. A total of 35 vegetable samples were collected from four markets in Dinajpur district. The isolates were identified using cultural, staining, biochemical, and molecular tests. Microbial loads were enumerated (TVC) using the pour plate technique. Molecular detection of bacterial species was confirmed targeting the 16S rRNA and groEL genes of E. coli and V. cholerae, respectively. The amplification was done on 704 bp fragments of the 16S rRNA gene of E. coli and 1117 bp fragments of Vibrio spp. For the confirmation of V. cholerae, amplification of a 418 bp fragment of the groEL gene was performed through multiplex PCR. An antimicrobial susceptibility test was conducted on all isolates of bacteria against eleven and eight antibiotics by disc diffusion. The total viable count (TVC) in potato, carrot, cabbage, cauliflower, tomato, green chili, cucumber, mustard sak, and coriander leaves were 2.4 ± 0.37, 2.2±0.14, 2.1±0.26, 1.8±0.14, 1.7±0.27, 1.5±0.33, 1.5±0.33, and 1.4±0.25 mean log colony forming units ± standard deviation/mg, respectively. Out of 35 raw vegetable samples, 16 (45.71%) and 13 (37.14%) isolates were culture positive for E. coli and V. cholerae. Subsequently, 5 (31.25%) and 4 (30.76%) isolates of E. coli and V. choleraewere confirmed positive molecularly. All 16 and 13 isolates of E. coli and V. cholerae were subjected to antibiogram testing against 11 and 8 antibiotics. E. coli isolates were highly resistant to ceftazidime, cefixime, ampicillin, and oxytetracycline, but sensitive to gentamycin, ceftriaxone, colistin, and enrofloxacin. Similarly, V. cholerae isolates were highly resistant to nalidixic acid, trimethoprim, and polymyxin, but highly sensitive to kanamycin, gentamicin, and streptomycin. The study’s findings indicate that raw vegetables pose a significant public health risk due to MDR E. coli and V. cholerae. To achieve safer levels of these bacteria in raw vegetables, good production practices and hygiene awareness are essential.

Electrochemical potential enhanced EC-SERS sensor for sensitive and label-free detection of acetamiprid

Label-free surface-enhanced Raman spectroscopy (SERS) holds promise for detecting pesticide residues, yet its broader application in food safety is limited by the weak affinity between pesticides and SERS substrates. This study introduces an electrochemical surface-enhanced Raman spectroscopy (EC-SERS) sensor that utilizes potential strengthened molecular interactions and Ag@SiO2 nanospheres as SERS substrates, significantly enhancing the detection sensitivity for acetamiprid (AAP). The dense distribution of silver nanoparticles (Ag NPs) on the SiO2 surfaces creates numerous “hot spots,” significantly improving the SERS performance for AAP detection. A potential of −0.5 V substantially boosts the SERS signal intensity for AAP compared to without applied potential, notably achieving a 4.3-fold increase at the 631 cm−1 signal peak. Under optimal conditions, the EC-SERS method achieved a limit of detection (LOD) for AAP at 0.046 μM, spanning a linear range from 0.05 μM to 0.1 mM, which is 185 times more sensitive than conventional SERS approaches. When applied to vegetable samples, the method showed recoveries between 95.56 % and 109.33 %, with results corroborated by HPLC-MS analysis. Thus, this study provides an effective and facile strategy for the detection of AAP in the food safety field.

Photosynthate, heavy metals contents, biochemical characteristics and anatomical responses in Telfairia occidentalis. and Amaranthus hybridus collected within akure metropolis

Heavy metals in soils pose a potential threat to the environment and can cause significant damage to human and animal health. This study aimed to assess heavy metal concentrations, photosynthate levels, biochemical characteristics, and anatomical responses in Telfairia occidentalis and Amaranthus hybridus collected within Akure metropolis, Ondo State, Nigeria. Fresh vegetable samples were randomly collected from four fertilized farmlands (denoted as A, B, C, and D) within the Akure metropolis. Heavy metal concentrations in the vegetable samples were determined using an Atomic Absorption Spectrophotometer (AAS). The pigment content (Chlorophyll a and b) of the vegetables was measured, while the activities of Catalase (CAT), Superoxide Dismutase (SOD), and reduced glutathione (GSH) were estimated. Stomatal architecture and epithelial cell structure were also analyzed. Results indicated that CAT (7.45 ± 0.36 U/mg protein) and SOD (6.21 ± 0.28 U/mg protein) activities, as well as GSH content (4.63 ± 0.12 µmol/g tissue), were highest in vegetables collected from farm A, showing statistically significant differences compared to other farms (p < 0.05). The concentrations of heavy metals in the leaves of vegetables collected from all farms were below the standard limits recommended by WHO/FAO, with the exception of Lead (Pb), which was significantly higher than the permissible limit in farm B (2.14 ± 0.09 mg/kg; p < 0.05). Chlorophyll content was significantly reduced in both vegetables compared to the control (chlorophyll a: 2.56 ± 0.21 mg/g tissue in T. occidentalis and 2.03 ± 0.19 mg/g tissue in A. hybridus; p < 0.05). This reduction in chlorophyll content correlated with the elevated levels of Pb in farm B (r = -0.87, p < 0.05). The stomatal architecture analysis revealed significant alterations in stomatal density and pore size in both vegetables from contaminated farms. These findings suggest the need for biomonitoring programs to control heavy metal accumulation in Nigerian farmlands, as elevated levels of Pb can disrupt the physiological and biochemical processes of vegetables, posing potential health risks to consumers.

Synthesis of fluorescent La:MnMoO4 perovskite oxide nanoprobe for detection of indoxacarb in food samples

Indoxacarb is widely applied as an insecticide that poses a risk of environmental contamination, indicating a facile and selective probe needs to be developed for indoxacarb assay in environmental and food samples. In this work, fluorescent La:MnMoO4 perovskite oxide nanomaterials are synthesized and used as a rapid fluorescent probe to detect indoxacarb in vegetable and fruit samples. The as-prepared La:MnMoO4 perovskite oxide showed blue fluorescence at 413 nm upon the excitation at 330 nm, however the fluorescence of La:MnMoO4 perovskite oxide can be efficiently quenched by indoxacarb through the inner filter mechanism. The sensor showed a satisfactory linear relationship with increasing amounts of indoxacarb in the range of 2.5–60 µM (R2 = 0.99) with a limit of detection (LOD) of 62.99 nM, displaying good recoveries in the range of 97.35–99.61 %. The developed La:MnMoO4 perovskite oxide-based fluorescent sensor could electively be applied for on-site assaying of indoxacarb in agricultural and environmental samples.

High-performance solid-phase microextraction based on a nanocomposite sorbent of MOF/COF hybrid for ultra-trace analysis of trifluralin in food samples using the ion mobility spectrometer

Two well-known porous hybrid materials, a metal-organic framework (MOF) based on manganese and a melamine-rich covalent organic framework (COF) were combined, resulting in a highly effective nanocomposite sorbent of Mn-terephthalic acid (TA) /COF. After investigating the properties of the synthesized adsorbent, it was finally used as a new fiber for solid-phase microextraction. The method, named high-performance solid-phase microextraction (HPSPME), was utilized for the extraction and ultra-trace analysis of trifluralin in agricultural waters, fruit, and vegetable samples by using corona discharge ionization-ion mobility spectrometer (CD-IMS). To increase the extraction efficiency, experimental parameters including, temperature and time of extraction and desorption, solution pH, and stirring rate were optimized. Considering the optimized conditions, the enrichment factor of 2002, the limit of detection (LOD) 0.08 ng mL−1 (S/N=3), and linear dynamic range (LDR) 0.25–10.00 ng mL−1 with a coefficient of determination (R2=0.9987) were obtained. Relative standard deviations (RSDs, n = 3) of <9.7, <3.5, and <8.9 % were obtained, respectively, for reproducibility of the prepared fibers, intra- and inter-day. The relative recovery values for the real samples were 84–124 %. The proposed method’s accuracy for the sample impregnated with trifluralin was also evaluated by the EPA standard method.

Selective Chromo-Fluorogenic Chemoprobe for nM Al3+ Recognition: Experimental and Living-Cell Applications.

A rhodamine based chemoprobe BESN was engineered and employed as a selective ''OFF-ON'' chromo-fluorogenic sensor for Al3+ in H2O:MeOH (1:9, v:v). Notable changes in the absorption and emission spectra of BESN were clearly detectable upon the addition of Al3+. Sensitivity and binding mechanism studies demonstrated a good sensing performance of BESN with nanomolar detection limit (130nM), and it was found to be highly selective towards interfering metal ions. Besides, the binding constant between BESN and Al3+ was found to be 3.19 × 103M-1. Then, the validation study of BESN for Al3+ was performed based on significant analytical parameters and statistical tests. The binding of Al3+ with BESN (1:1) was probed via infrared, high-resolution mass and emission (Job's plot) spectroscopy measurements. The sensing performance of BESN could make it ideal chemosensor for real applications including vegetable, tuna fish and water samples, also for Smartphone and test-kit applications. The recovery values of the BESN to Al3+ were estimated within a range from 95.13% to 105.30% for water, 94.63% to 109.62% for tuna fish and 94.80% to 109.80% for vegetable samples. Additionally, the BESN has very low cytotoxicity and was triumphantly utilized for the recognition of Al3+ in living-cells.

Determination Ca, Cu, Fe, Mn, and Zn release from food in simple gastrointestinal extraction test

In this study, by conducting simulated in vitro digestion experiments on samples, the extraction rates of several essential metal elements in some common food ingredients were determined to guide a rational and balanced diet. At the same time, taking vegetables as an example, the research investigated the impact of food preprocessing on the extraction rates of metal elements within them, demonstrating that the influence of heat treatment varies for different element extraction rates. A wet digestion system using nitric acid-hydrogen peroxide was established for seafood and vegetable samples, and an analytical method for determining Ca, Cu, Fe, Mn and Zn using inductively coupled plasma optical emission spectrometry (ICP-OES) was developed. The detection limits of the method ranged from 0.0003 mg L−1 to 0.1567 mg L−1, with RSDs between 0.004% and 7.161%. The measured contents of several important metal elements in standard substances were largely consistent with national standards, confirming the accuracy and precision of the method. Based on wet digestion, the contents of various metal elements in simulated digestive fluids were determined. The detection limits for the simulated digestion method ranged from 0.0005 mg L−1 to 0.0077 mg L−1, with RSDs between 0.001% and 8.839%, verifying the precision of the method. Consequently, the extraction rates of metal elements in the two types of samples were obtained, leading to the conclusion that vegetable samples are more easily digested compared to seafood, releasing their metal elements. Moreover, the extraction rates of different elements vary within the same type of sample, and the extraction rates of the same element also differ across different samples. For dried fruit samples, a dry ashing digestion system was established, and an analytical method for determining Ca, Cu, Fe, Mn and Zn using ICP was developed. The detection limits of this method ranged from 0.0003 mg L−1 to 0.0073 mg L−1, with RSDs between 0.001% and 1.076%, and the spiked recovery rates were between 85.43% and 105.96%, confirming the accuracy and precision of the method. Based on dry ashing digestion, the contents of various metal elements in simulated digestive fluids were measured, which led to the determination of the element extraction rates. Among these, the extraction rates for Ca, Cu, and Mn were relatively high.

Organophosphate esters in terrestrial environments of Fildes Peninsula, Antarctica: Occurrence, potential sources, and bioaccumulation

Despite growing concerns regarding the long-range transport (LRT) and ecological risks of organophosphate esters (OPEs), information on the environmental behaviors of OPEs in polar terrestrial ecosystems remains inadequate. In the present study, 10 OPEs were analyzed in soil and vegetation samples collected from Fildes Peninsula, Antarctica. The OPE concentrations in Antarctic soils, mosses, and lichens ranged from 0.87 to 15.7 ng/g dry weight (dw), 9.8 to 113 ng/g dw, and 3.6 to 75.2 ng/g dw, respectively. Non-chlorinated OPEs predominated in terrestrial matrices, accounting for approximately 76 % of the OPE composition. Source identification indicated that OPE contamination in Antarctica likely resulted from local anthropogenic sources and LRT. Moreover, the bioaccumulation behavior of OPEs from soil to vegetation was assessed using bioconcentration factors (BCFs), revealing a significant non-linear trend of initial increase and subsequent decrease in BCFs relative to the lipophilicities of the octanol-air partition coefficient (log KOA) and octanol-water partition coefficient (log KOW). While low levels of OPEs in Antarctic terrestrial environments were reported in this study, their sustained inputs and potential ecological risks in polar regions warrant further attention.