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This study aimed to assess the concentrations of major and trace metals (Na, Ca, Fe, Zn, Ni, Mn, Cu, Cd, and Pb) in date palm fruit samples collected from diverse regions, including Afar (Ethiopia), Iraq, and Saudi Arabia, utilizing flame atomic absorption spectrometry (FAAS). The wet acid digestion method was employed for sample treatment, with optimization of the key parameters such as reagent volume ratio, oven temperature, and digestion time for analytical applications. Under the optimized parameters, average metal concentrations in date palm fruit samples ranged from 205-299, 134-320, 38.8-115, 25.1-42.2, 9.27-27.9, 7.11-16.3, and 0.002-1.15 mg/kg for Ca, Na, Fe, Ni, Zn, Mn, and Cu, respectively. Cd and Pb levels were below detection limits within the linear range. Generally, date palm samples exhibited higher Ca and Na contents and lower concentrations of Cu and Mn than other metals. Pearson correlation analysis revealed very strong positive correlations between Fe and Na, Na and Zn, Na and Mn, Ca and Zn, Fe and Ni, Fe and Mn, and Mn and Ni. Strong negative correlations were observed for Ni and Na, Fe and Cu, and Cu and Ni. Weak correlations were noted among Na and Cu, Ca and Fe, Ca and Ni, Ca and Mn, Ca and Cu, Fe and Zn, Ni and Zn, Zn and Mn, and Zn and Cu. A recovery study using the spiking method demonstrated acceptable percentage recoveries ranging from 91.6% to 97.8%. Health risk assessment, including chronic daily intake (CDI), hazard quotient (HQ), total exposure hazard index (HI), and carcinogenic risk (CR), indicated CDI, HQ, and HI values below 1.0, except for the HI value for Ni. This suggests that the metals pose no probable public health risk, with the absence of Cd and Pb in date palm samples affirming no carcinogenic threats associated with their consumption.

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In this study, we have developed a novel, hypersensitive, and ultraselective electrochemical sensor containing thermally annealed gold-silver alloy nanoporous matrices (TA-Au-Ag-ANpM) integrated with f-MWCNTs-CPE and poly(l-serine) nanocomposites for the simultaneous detection of sulfathiazole (SFT) and sulfamethoxazole (SFM) residues in honey, beef, and egg samples. TA-Au-Ag-ANpM/f-MWCNTs-CPE/poly(l-serine) was characterized using an extensive array of analytical (UV-Vis, FT-IR, XRD, SEM, and EDX), and electrochemical (EIS, CV and SWV) techniques. It exhibited outstanding performance over a wide linear range, from 4.0 pM to 490 µM for SFT and 4.0 pM to 520 µM for SFM, with picomolar detection and quantification limits (0.53 pM and 1.75 pM for SFT, 0.41 pM and 1.35 pM for SFM, respectively). The sensor demonstrated exceptional repeatability, reproducibility, and anti-interference capability, with percentage recovery of 95.6-102.4% in food samples and RSD below 5%. Therefore, the developed sensor is an ideal tool to address the current antibiotic residue crisis in food sources.

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BACKGROUND: The widespread use and abuse of antibiotics has resulted in the pollution of water sources with antibiotic residues, posing a threat to human health, the environment, and the economy. Therefore, a highly sensitive and selective method is required for their detection in water samples. Herein, advanced ultrasensitive electrochemical sensor platform was developed by integrating gold-silver alloy nanocoral clusters (Au-Ag-ANCCs) with functionalized multi-walled carbon nanotube-carbon paste electrode (f-MWCNT-CPE) and choline chloride (ChCl) nanocomposites for simultaneously determining the residues of antimicrobial drugs, rifampicin (RAMP) and norfloxacin (NFX), in water samples. RESULTS: The developed sensor (Au-Ag-ANCCs/f-MWCNTs-CPE/ChCl) was extensively characterized using several analytical (UV-Vis, FT-IR, XRD, SEM, and EDX) and electrochemical (EIS, CV, and SWV) techniques. It exhibited outstanding performance in a wide linear range, from 14 pM to 115 µM for RAMP, and from 0.9 nM to 200 µM for NFX, with a limit of detection (LOD, 3σ/m, S/N = 3, n = 5) and a limit of quantification (LOQ, 10σ/m, S/N = 3, n = 5) values of 2.7 pM and 8.85 pM for RAMP, and 0.14 nM and 0.47 nM for NFX, respectively. The sensor also exhibited exceptional reproducibility, stability, and resistance to interference. SIGNIFICANCE: The developed sensor was effectively utilized to determine RAMP and NFX residues in hospital wastewater, river, and tap water samples, yielding recoveries within the range of 96.8-103 % and relative standard deviations below 5 %. Generally, the proposed sensor demonstrated remarkable performance in detecting the target analytes, making it an ideal tool and the first of its kind for addressing global antibiotic residue pollutants in water sources.

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The widespread use and misuse of antibiotics in pharmaceuticals and animal farming has resulted in their accumulation in food sources and the environment, posing significant threats to human health, the environment, and the global economy. In this study, we have developed a hypersensitive, and ultra-selective electrochemical sensor, the first of its kind, by integrating a thermally annealed gold-silver alloy nanoporous matrix (TA-Au-Ag-ANpM) with reduced graphene oxide (r-GO) and poly(glycine) at the surface of a glassy carbon electrode (GCE). This sensor aims to detect life-threatening metronidazole (MTZ) residues in food samples. TA-Au-Ag-ANpM/r-GO/poly(glycine)/GCE was thoroughly characterized using a range of analytical techniques, including UV-Vis, FT-IR, XRD, SEM, and EDX. Furthermore, its electrochemical properties were investigated by cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS). The sensor exhibited outstanding performance, with a broad linear range of 2.0 pM-410 µM. The limits of detection (LOD) and quantification (LOQ) were determined to be 0.0312 pM and 0.104 pM, respectively. The TA-Au-Ag-ANpM/r-GO/poly(glycine)/GCE exhibited exceptional reproducibility, repeatability, stability, and resistance to interferences. Moreover, the sensor demonstrated outstanding performance in detecting MTZ residues in milk powder, pork, and chicken meat samples, achieving very good recoveries (96.9%-101.4%) with a relative standard deviation (RSD) below 5%. This performance highlights the potential for practical applications in food safety and quality monitoring. Therefore, the developed sensor contributes to the advancement of electrochemical sensing technology and its application in ensuring food safety and integrity by combating antibiotic residues.

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In this study, for the first time, the levels of thirteen micro- and macromineral nutrients in the leaves, seeds, and supportive soil of Moringa stenopetala (M. stenopetala) were simultaneously determined using microwave plasma atomic emission spectroscopy (MP-AES). The samples were collected during the arid season, in 2019 from the three main M. stenopetala growing areas in southern Ethiopia (Chano Mile Kebele, Nechisar Kebele, and Konso Special Woreda). A novel digestion method for leaf and seed samples was developed using an optimized acid mixture (2.5 : 0.75 : 0.5 of HNO3, HClO4, and H2O2) at 240°C for 2 hrs and 30 min, resulting in clear and colorless solutions. The method makes the digestion process more efficient by minimizing the reagent volume, reducing digestion temperature and time, and simplifying the overall procedure. The efficiency of the optimized procedure was validated by spiking experiments, and the percentage recovery ranged between 94 and 110%. Under optimized experimental conditions, higher concentrations of essential minerals (K, Na, Ca, and Mg) were observed in the plant leaf and seed samples from the three areas. In addition, significant amounts of trace elements (Fe, Mn, Zn, and Cu) were also found. Importantly, no traces of the toxic elements (Cd and Pb) were detected in any of the analyzed samples, suggesting that the leaves and seeds of M. stenopetala are valuable sources of both micro- and macromineral nutrients and are safe from toxic metals. From a dietary perspective, the seed contains almost comparable concentrations of minerals as the leaves. As a result, the seeds of M. stenopetala can serve as an alternative source of minerals and play a role in overcoming the current global food crisis, particularly in the dry season. Analysis of variance at a 95% confidence level revealed significant differences in the levels of all mineral nutrients between the three sample means except K, Ca, Co, and Cu. Generally, the developed method includes an innovative digestion procedure that minimizes reagent consumption, operates at lower temperatures, and requires shorter digestion times, thereby optimizing resource utilization and maintaining analytical accuracy. Notably, the absence of toxic elements in the MP-AES procedure highlights the safety and reliability of M. stenopetala leaves and seeds as valuable, contamination-free sources of essential nutrients.