Low LOD Research Articles

Determination and health risk assessment of carbamate pesticide residues in date palm fruits (Phoenix dactylifera) using QuEChERS method and UHPLC-MS/MS

This study aimed to investigate carbamate pesticide residues in different varieties of date palm fruits in the UAE, utilizing UHPLC-MS/MS. For sample preparation and clean-up, the efficiency and performance of different QuEChERS dispersive solid-phase extraction kits were compared. Precision and recovery were assessed at 10 μg kg−1 for the three kits, revealing that Kit 2 demonstrated the best performance. The selected QuEChERS method was validated to detect 14 carbamate residues in 55 date samples. The method exhibited strong linearity with R2 > 0.999 and low LOD (0.01–0.005 μg kg−1) and LOQ (0.003–0.04 μg kg−1). Excellent accuracy (recovery: 88–106%) and precision (RSD: 1–11%) were observed, with negligible matrix effect (− 4.98–13.26%). All samples contained at least one carbamate residue. While most detected residues were below their MRLs, carbosulfan was found in 21 samples, propoxur in 2 samples, and carbofuran in 1 sample above their MRLs. The hazard index (HI) was calculated for carbosulfan, phenmedipham, carbaryl, propoxur, carbofuran, and methomyl to assess potential health risks for date consumers. All HI values were below the safety limit of 1.0, indicating that the consumption of dates does not pose a non-carcinogenic health risk for adults and children.

Ultrafast and Parts-per-Billion-Level MEMS Gas Sensors by Hetero-Interface Engineering of 2D/2D Cu-TCPP@ZnIn2S4 with Enriched Surface Sulfur Vacancies.

The primary challenge for resonant-gravimetric gas sensors is the synchronous improvement of the sensitivity and response time, which is restricted by low adsorption capacity and slow mass transfer in the sensing process and remains a great challenge. In this study, a novel 2D/2D Cu-TCPP@ZnIn2S4 composite is successfully constructed, in which Cu-TCPP MOF is used as a core substrate for the growth of 2D ultrathin ZnIn2S4 nanosheets with well-defined {0001} crystalline facets. The Cu-TCPP@ZnIn2S4 sensor exhibited high sensitivity (1.5 Hz@50 and 2.3 Hz@100 ppb), limit of detection (LOD: 50 ppb), and ultrafast (9 s @500 ppb) detection of triethylamine (TEA), which is the lowest LOD and the fastest sensor among the reported TEA sensors at room temperature, tackling the bottleneck for the ultrafast detection of the resonant-gravimetric sensor. These above results provide an innovative and easily achievable pathway for the synthesis of heterogeneous structure sensing materials.

Ultrasensitive detection of trace Hg(Ⅱ) in acidic conditions using DMABR loaded on sepiolite: Function, application and mechanism studies

Fast and real-time detection of trace Hg(Ⅱ) by fluorescent probes under acidic conditions is urgently required due to the high toxicity and accessibility to creatures and human being. However, fluorescent probes for Hg(Ⅱ) detection in environmental samples are rarely reported due to the protonation potential of acidic mercury sources. In this study, the SD probe was developed by 5-(p-dimethylaminobenzylidene) rhodanine (DMABR) loaded on sepiolite by hydrothermal treatment, and showed excellent Hg(Ⅱ) detection performances for mercury sources at pH 4–10 due to buffering ability of the hyperconjugated lactam rings. Sepiolite functioned as the support skeleton to decrease intermolecular transition, and thus increased the sensitivity. At pH 4, the SD probe showed high selectivity and sensitivity for Hg(Ⅱ) among various species, with low LOD and binding constant of 4.78 × 10−9 M and 1.34 × 106 M−1, respectively. Through DFT calculations, MAS 1H NMR and 2D-COS analysis, the detection mechanism was demonstrated as SN1 substitution of the spontaneous leaving H on amino groups in the transient state during tautomeric equilibrium, rather than the expected high-affinity sulphydryl. Additionally, the SD probe exhibited promising potential in quantifying water-soluble and bioavailable Hg(Ⅱ) in acidic polluted soil and water samples. Moreover, real-time detection was realized by paper-based strips.

Selective extraction and analysis of phenolic acids in herbal plants using Fe3O4@MXene@PEI aerogel

A magnetic MXene aerogel (Fe3O4@MXene@PEI) was prepared by crosslinking amino modified MXene with polyethyleneimine using epichlorohydrin as a cross-linker. Adsorption properties of Fe3O4@MXene@PEI aerogel for phenolic acids were evaluated by adsorption kinetics and isotherms experiments, showing that the high adsorption affinity was governed by multilayer chemisorption process. An efficient MSPE/HPLC method was developed for the determination of phenolic acids with excellent selectivity, good linearity (0.025–5.0 μg mL−1), low LODs (0.007–0.017 μg mL−1), and satisfactory recoveries (80.0–120.0 %). Moreover, the antioxidant activity of the Fe3O4@MXene@PEI purified compounds was superior to that of the conventional method as demonstrated by the results of scavenging experiments on 2,2 -diphenyl-1-picrylhydrazyl radical scavenging assay. Finally, 65 organic acids were identified in the Fe3O4@MXene@PEI treated honeysuckle extracts by UHPLC-Q-Exactive Orbitrap MS/MS analysis. The proposed sorbent exhibits remarkable promise for the selective separation and purification of organic acids from herbal products.

An innovative approach for selective and robust screening of NBOHs, NBOMes, and LSD in forensic samples using a 3D-Printed electrochemical double cell

Lysergic acid diethylamide (LSD) and two phenethylamine classes (NBOHs and NBOMes) are the main illicit drugs found in seized blotter papers. The preliminary identification of these substances is of great interest for forensic analysis. In this context, this work constitutes the inaugural demonstration of an efficient methodology for the selective detection of LSD, NBOHs, and NBOMes, utilizing a fully 3D-printed electrochemical double cell (3D-EDC). This novel 3D-EDC enables the use of two working electrodes and/or two supporting electrolytes (at different pHs) in the same detection system, with the possibility of shared or individual auxiliary and pseudo-reference electrodes. Thus, the selective voltammetric detection of these substances is proposed using two elegant strategies: (i) utilizing the same 3D-EDC platform with two working electrodes (boron-doped diamond (BDD) and 3D-printed graphite), and (ii) employing two pH levels (4.0 and 12.0) with 3D-printed graphite electrode. This comprehensive framework facilitates a fast, robust, and uncomplicated electrochemical analysis. Moreover, this configuration enables a rapid and sensitive detection of LSD, NBOHs, and NBOMes in seized samples, and can also provide quantitative analysis. The proposed method showed good stability of the electrochemical response with RSD <9 % for Ip and <5 % for Ep, evaluating all oxidation processes observed for studied analytes (n = 7) at two pH levels, using the same and different (n = 3) working electrodes. It demonstrates a broad linear range (20–100 and 20–70 μmol L−1) and a low LOD (1.0 μmol L−1) for quantification of a model molecule (LSD) at the two pHs studied. Hence, the 3D-EDC combined with voltammetric techniques using BDD and 3D-printed graphite electrodes on the same platform, or only with this last sensor at two pH values, provide a practical and robust avenue for preliminary identification of NBOHs, NBOMes, and LSD. This method embodies ease, swiftness, cost-efficiency, robustness, and selectivity as an on-site screening tool for forensic analysis.

Bifunctional colloid based on anchoring reactions in-situ modified electrodes: For electrochemical sensing and HER

In this study, a bifunctional [PtCl6]2−-GO colloidal material was prepared by anchoring [PtCl6]2− by abundant oxygen-containing functional groups in protonated graphene oxide. Two modification strategies, surface overcoating and electrochemical in situ deposition, were adopted to modify the screen-printed carbon electrode (SPCE), foam electrodes (CuF, NiF), respectively, and Pt-rGO, which uniformly covered the electrode surface, was obtained by a simple onestep of reducing [PtCl6]2−-GO. The effectiveness of the modified materials and electrode modification strategies prepared was validated by tinidazole electrochemical detection and hydrogen evolution reaction (HER). The results indicated that the Pt-rGO modified SPCE possessed lower LOD and higher sensitivity for the detection. Furthermore, as for HER, optimized Pt-rGO-modified NiF and CuF required only 26 mV and 76 mV overpotentials in alkaline and acidic solutions, respectively, to obtain current densities of 10 mA cm−2. This was largely ascribed to the synergistic interaction between platinum and rGO, with the synthesized platinum-rGO displaying stronger active sites and higher intrinsic activity. In particular, Pt, which acts as an active center, could offer part of its electron to H2O and adjacent reduced graphene oxide sites, thus promoting strong electrical connections and efficient HER kinetics.

Synergistic effect of inner filtering effect and host-guest interaction based on β-cyclodextrin fluorophore for promoted 4-nitrophenol detection

Efficient detection of 4- nitrophenol (4-NP) organic pollutant is always a very important issue due to the rapid development of chemical industry and the abuse of pesticides and so on. Here, we designed and synthesized a novel supramolecular fluorescent probe, 4-[4-(acetylamino)styryl]-1-cyclodextrin pyridinium p-toluenesulfonate (ASPT-β-CD), for the selective and sensitive detection of 4-NP. The introduction of β-CD not only improves the water solubility of probe and can also be used as a host to encapsulate 4-NP. In alkaline aqueous solution, the absorption spectrum of 4-NP overlaps the excitation spectrum of ASPT-β-CD and suggests that an internal filtration effect occurs between them. We explored the possible response mechanism and speculated that the high selectivity and high sensitivity were derived from the synergistic effect of inner filtering effect and host-guest interaction. Benefiting from the synergistic effect, the proposed sensor ASPT-β-CD displayed significant "turn-off" after adding 4-NP, while showing a fast response to 4-NP within 2 min and low LOD about 0.01 μM. In addition, this method has been successfully applied to the determination of 4-NP in lake water samples, indicating that the obtained ASPT-β-CD has great practical application potential in the environmental field.

A dual-mode sensing system for xanthine oxidase detection based on nitrogen-doped carbon dots and iron-cobalt oxide nanosheets

As one of the existing forms of xanthine oxidoreductase, xanthine oxidase (XOD) exists in many human tissues, and the overactivity of XOD will result in some serious illnesses such as gout and diabetes. Herein, a novel dual-signal sensing system for XOD activity determination was proposed based on fluorescent nitrogen-doped carbon dots (N-CDs) and iron-cobalt oxide nanosheets (FeCo-ONSs). XOD has the ability to oxidise xanthine to uric acid while also producing H2O2. As a sort of peroxidase-like enzyme, FeCo-ONSs can catalyze H2O2 to produce reactive oxygen species (ROS). And N, N-Diethyl-p-phenylenediamine sulfate salt (DPD) was oxidized to DPDox that serves as a chromogenic substrate in the presence of ROS, causing the colorless solution to turn pink. DPDox exhibits two characteristic absorption peaks at 551 nm and 512 nm and it can also efficiently quench the fluorescence emission of N-CDs at 500 nm. Therefore, the fluorometric and colorimetric dual-channel sensing platform was established to assay XOD with the lower LOD of 0.00522 mU/mL and 0.0177 mU/mL, respectively. Additionally, the dual-output strategy was found to be applicable to the quantitative analysis of XOD in serum samples with good reliability and selectivity.

Sensitive and selective antioxidant curcumin analysis using anionic surfactant modified glassy carbon electrode

This paper presents a sensitive and selective curcumin (CCM) voltammetric procedure using a glassy carbon electrode covered with asodium dodecyl sulfate layer (GCE/SDS) in 0.2 M CH3COOH. The developed sensor and the behavior of CCM on its surface were investigated by voltammetric and impedance techniques. According to the results, the GCE/SDS shows electrocatalytic properties in relation to oxidation of CCM and the redox Fe(III)/Fe(II) system. The concurrent process of preparing sensors and conducting CCM measurements is marked by its ease of implementation, minimal reagent usage, and affordability. The use of CCM accumulation at 0 V for 120 s allows gaining the linearity of the calibration curve from 0.001 to 20.0 nM, with an extremely low LOD of 0.00027 nM. Ultimately, the established procedure was effectively employed for the analysis of food samples, including spice extracts and energy shots, and the results are consistent with chromatography measurements.

Bimetallic Fe/Co nanoalloy embedded in porous carbon as electrochemical sensor for acetaminophen detection

Ferro-alloys have been extensively studied in the field of electrochemical sensing due to their abundant earth reserves and excellent performances. In this work, serials of bimetallic Fe/Co nanoalloy@carbon composites (Fe/Co@C) were successfully prepared using Co-doped MIL-101(Fe) as templates and developed as excellent electrochemical sensors for acetaminophen (AP) detection. It was found that the atomic ratio of Fe/Co in the templates can significantly affect the electrochemical activity of the product. Among the prepared composites, Fe/Co@C-G2 (Fe/Co = 2:1) with high conductivity and large specific surface area presents the best electrochemical sensing performance. Under the optimal conditions, Fe/Co@C-G2 has a high sensitivity of 55.2 [Formula: see text]A [Formula: see text][Formula: see text] [Formula: see text], a wide linear range of 0.29-407.15 [Formula: see text]M, a low LOD of 0.09 [Formula: see text]M, good selectivity, excellent stability, and good repeatability. In addition, Fe/Co@C-G2 can also be used for real sample testing. This work expands the application of Fe/Co@C-based composites in electrochemical sensing.

LC-MS analysis of polar and highly polar organic pollutants in Barcelona urban groundwater using orthogonal LC separation modes.

Groundwater samples may contain thousands of organic pollutants from infiltration of surface water, sewer leakages, and to a minor extent from public water supply network losses. Polar (0 < log D < - 2.0) and very polar substances (log D < - 2.0) have been largely beyond the scope of applied analytical methodologies in environmental monitoring because of challenges related to their extraction from the sample and subsequent chromatographic separation. In this study, we developed an analytical workflow for 96 pollutants covering a broad polarity range, including pharmaceuticals, industrial chemicals, and artificial sweeteners, potentially seeping through the soil in urban areas. The Besos aquifer located at the Northern-eastern edge of the city of Barcelona was chosen as a study area due to the deterioration of the quality of the aquifers over the past years and the proven presence of numerous pollutants. The methodology consisted of vacuum-assisted evaporation (VAE) followed by chromatographic separation of the sample on two columns with orthogonal retention mechanisms, namely, an HSS T3 column (modified C18) and a BEH amide column (HILIC). The analytes were detected by high-resolution mass spectrometry on a Q Exactive Orbitrap system in data-independent acquisition mode. Taking into consideration the retention as well as the peak shape, a Quality Score (QS) was assigned for each analyte to evaluate the quality of each chromatographic peak of each compound. While 67 compounds, including 19 polar and 48 moderately polar, were satisfactorily retained on an HSS T3, 29 compounds, including 14 highly polar, 14 polar, and one moderately polar, were analyzed in the BEH amide column. The optimized methodology was applied for the analysis of 89 out of 96 validated contaminants with satisfactory recoveries in samples collected from seven wells, providing low LODs (0.02 to 0.45ng L-1) and LOQs (0.06 to 1.34ng L-1). A number of highly polar and polar compounds not previously reported to occur in GW, including artificial sweeteners, pharmaceuticals, and industrial chemicals, were detected at concentrations as high as few g L-1.

A Facile Determination of Herbicide Residues and Its Application in On-Site Analysis.

Abuse of herbicides in food safety is a vital concern that has an influence on the sustainable development of the world. This work presents, a modified ionization method with separation of the sample and carrier gas inlets, which was utilized for efficient ionization and analyte transfer of herbicides in crops. The working parameters of voltage, injective distance, desorption temperature, and the carrier gas flow rate were optimized to achieve the high efficiency of the transfer and ionization of the analyte. When it was applied in the analysis of herbicides in laboratory, the method exhibited excellent performance in achieving the quantitative detection of herbicides in solutions and residues spiked in an actual matrix with a limit of quantification of 1-20 μg/kg and relative standard deviations of less than 15%. Although a simple QuEchERS process was used, the programmable heating platform ensured efficient gasification and transfer of the target analyte, with the advantages of high speed and selectivity, avoiding the noted matrix effect. The method exhibited a relatively acceptable performance by using air as the discharged gas (open air). It could be used to monitor herbicide residues in the growth stage via on-site non-destructive analysis, which obtained low LODs by dissociating the herbicides from the crops without any pretreatment. It showed great potential for the supervision of the food safety market by achieving non-destructive detection of crops anytime and anywhere. This finding may provide new insights into the determination of pesticide emergence and rice quality assessment.

Cresyl violet electropolymerization on functionalized multiwalled carbon nanotubes in carboxylic acid based ternary deep eutectic solvents for hydroquinone sensing

The phenazine dye cresyl violet (CVio) has been evaluated as precursor for the preparation of a new electrochemical sensor based on poly(cresyl violet) deposited on multiwalled carbon nanotube (CNT) modified glassy carbon electrodes (GCE) in neutralized acid-doped ternary deep eutectic solvents (DES). DES with choline chloride as hydrogen bond acceptor and with different hydrogen bond donors (HBD), namely acetic acid, ethylene glycol and oxalic acid were evaluated for CVio electropolymerization by potential cycling. The best polymer films were obtained in ternary DES with the two HBD acetic acid plus ethylene glycol doped with H2SO4 and followed by NaOH neutralization. Electrochemical characterization (voltammetric and electrochemical impedance) showed the formation of anthraquinone groups during electropolymerization, which is initiated on the CNT by the formation of a cation radical. Anthraquinones in the polymer film led to an increased response at the modified electrode for the determination of hydroquinone (H2Q) with low LOD (0.25 µmol L−1) in a broad linear range (1–80 µmol L−1), with good reproducibility, repeatability, and stability. The sensor was successfully applied to the quantification of H2Q in dermatological creams with no matrix effect towards hydroquinone response.

Quantification of Etoricoxib in Low Plasma Volume by UPLC-PDA and Application to Preclinical Pharmacokinetic Study.

An ultra-performance liquid chromatography with photodiode array (UPLC-PDA) UV detection method was developed here for the first time for simple, rapid, selective and sensitive quantification of the commonly prescribed selective cyclooxygenase-2 (COX-2) inhibitor etoricoxib in low plasma volumes (50 μL). The method includes protein precipitation followed by liquid-liquid extraction, evaporation and reconstitution. A gradient mobile phase of 75:25 going to 55:45 (v/v) water:acetonitrile (1 mL/min flow rate) was applied. Total run time was 8 min, representing a significant improvement relative to previous reports. Excellent linearity (r2 = 1) was obtained over a wide (0.1-12 µg/mL) etoricoxib concentration range. Short retention times for etoricoxib (4.9 min) and the internal standard trazodone (6.4 min), as well as high stability, recovery, accuracy, precision and reproducibility, and low etoricoxib LOD (20 ng/mL) and LOQ (100 ng/mL), were achieved. Finally, the method was successfully applied to a pharmacokinetic study (single 20 mg/kg orally administered etoricoxib mini-capsule) in rats. In conclusion, the advantages demonstrated in this work make this analytical method both time- and cost-efficient for drug monitoring in pre-clinical/clinical settings.

Application of continuous magnetic solid phase extraction in the extraction of tetracycline antibiotics from honey samples

This study aimed to develop a continuous magnetic solid phase extraction method in a narrow bore tube for the extraction of tetracycline antibiotics from honey samples before their determination with high performance liquid chromatography–diode array detector. In this work, a magnetic covalent organic framework is used as the sorbent. The extraction method is performed in a narrow bore tube by adding 25 mg of a magnetic sorbent prepared from melamine, barbituric acid, and Fe3O4 into the diluted honey sample solution. By using a magnet, the sorbent is moved up and down through the narrow bore tube for five times to improve extraction efficiency. After adsorption the analytes, they are eluted from the sorbent surface using 2,2–dimethoxypropane under vortexing. Then, by using a magnet, the eluent containing the extracted analytes are taken and evaporated with continuous flow of nitrogen. Finally, the residue containing the enriched analytes is reconstituted in microliter–level of mobile phase and injected into chromatographic system for quantitative analysis. Based on the outcomes, the method demonstrated good linearity (0.37–1000 ng g−1), high enrichment factors (175–203), good extraction recoveries (70–81 %), low LODs (0.11–0.18 ng g−1) and LOQs (0.37–0.60 ng g−1). The proposed method is effectively applied for quantification of tetracyclines in twenty–four honey samples. Considering the results, none of the honey samples was contaminated with the studied antibiotics. Regarding to the above–mentioned analytical advantages of the proposed method, its simplicity and rapidity, and green synthesis of the magnetic sorbent particles, the suggested method can be used as a routine method for the extraction of tetracyclines from honey samples.

Enhanced cysteine sensor based on modified gold nanoparticles with synergistic role of pH-responsive poly (N,N-dimethylaminoethyl methacrylate)

The development of a highly sensitive and easy-to-prepare sensor for the detection of cysteine (Cys) is of great importance. Gold nanoparticles (AuNPs) have been frequently utilized as a Cys sensor owing to high affinity of the thiol group to gold. However, the presence of additional materials, such as stabilizers, can impact the sensitivity of this sensor. Herein, pH-sensitive gold nanoparticles (Au-PDA) were synthesized using poly (N,N-dimethylaminoethyl methacrylate) (PDMAEMA) for the purpose of Cys detection based on the aggregation size-dependent optical property of gold nanoparticles. Detection of cysteine was also followed by UV–Vis analysis, showing a decrease in intensity of localized surface plasmon resonance (LSPR) peak, a red shift from 525 to 550 nm as well as the appearance of a new peek at 650 nm. To enhance sensor performance, systematic investigations were conducted to optimize sensing conditions, focusing on pH, gold concentration, and ionic strength of the medium. Remarkably, the proposed sensor exhibited excellent selectivity towards Cys compared to other amino acids. The sensitivity of the sensor was evaluated using two methods: changes in the absorption intensity and the LSPR shift. The pH-sensitivity of PDMAEME led to a significant improvement in sensing parameters through a synergistic effect on the Au-Cys interaction, leading to a remarkably low LOD of 0.0004 nM, which is the lowest ever reported LOD for detection of Cys. Finally, practical application of the proposed sensor was validated in human blood serum.

Fabrication of molecularly imprinted carbon nanotubes integrating ionic liquids for efficient detection of perfluoroalkyl carboxylic acid in environmental water

It is extremely significant while challenging to accurately detect low-levels of perfluoroalkyl carboxylic acid compounds (PFCAs) in environmental water. Herein, adopting perfluorotetradecanoic acid as the dummy template, selective molecularly imprinted composites (CNTs@ILs@MIPs) grafted carbon nanotubes integrating hydrophilic ionic liquids were successfully prepared via surface imprinting and dummy-template imprinting techniques. The obtained CNTs@ILs@MIPs were applied as selective extraction adsorbent for specifically extract PFCAs in environmental water coupled with gas chromatography-mass spectrometry quantification. Detailed studies were conducted on the main preparation parameters and extraction conditions. The CNTs@ILs@MIPs displayed excellent adsorptivity, and the established method exhibited low LODs (0.60–1.64 ng L−1), wide linearity with R2 above 0.9994, and satisfactory adsorption recoveries (80.5–112.5%) for seven PFCAs. This proposed method provides a new applicable approach for the detection of targeted pollutants in environmental water by utilizing the high affinity and recognition ability of molecularly imprinted carbon nanotube functional materials modified with ionic liquids.

Utilization of Schiff base-Co(II) complex as a stable luminescent probe for the highly selective detection of 2,4,6-trinitrophenol in an aqueous medium

In this study, the fluorescence properties of Co(II) Schiff base complex (Co(II) complex) were examined. The sensor properties of the Co(II) complex nitroaromatic compounds [(DNB, TNT, DNT, 2-NP, 4-nitrophenol (NP), 2,4-dintrophenol (DNP) and 1,3,5-trinitrophenol (TNP) e.g.,] were investigated by fluorescence spectroscopy. Compound has high sensitivity for the sensing of 1,3,5-trinitrophenol (TNP) (Ksv: 4.74 × 104 M−1) with low LOD of 0.034 μM. It was revealed that the complex ([CoLCl(H2O)2]∙2H2O) exhibited strong fluorescence properties. Additionally, the synthesized Co(II) complex was utilized for fluorescence quenching-based TNP detection in water solution with high selectivity and sensitivity. The stoichiometry of the compound and TNP was found to be 1:1 (ligand/TNP) via fluorescence titrations (Job's plot).

A Multifunctional CaII-EuIII Heterometallic Organic Framework with Sensing and Selective Adsorption in Water.

With increasing global industrialization, it is urgent and challenging to develop multifunctional species for detection and adsorption in the environment. For this purpose, a novel anionic heterometallic organic framework, [(CH3)2NH2][CaEu(CAM)2(H2O)2]·4H2O·4DMF (CaEuCAM), is hydrothermally synthesized based on chelidamic acid (H3CAM). Single crystal analysis shows that CaEuCAM features two different oxygen-rich channels along the c-axis in which one CAM3- bridges two sextuple-coordinated Ca2+ and two octuple-coordinated Eu3+ with a μ4-η1: η1: η1: η1: η1: η1 new chelating and bridging mode. The characteristic bright red emission and superior hydrostability of CaEuCAM under harsh acidic and basic conditions benefit it by acting as a highly sensitive sensor for Fe3+ and 3-nitrophenol (3-NP) with extremely low LODs through remarkable quenching. The combination of experiments and theoretical calculations for sensing mechanisms shows that the competitive absorption and interaction are responsible for Fe3+-induced selective emission quenching, while that for 3-NP is the result of the synergism of host-guest chemistry and the inner filter effect. Meanwhile, the assimilation of negative charge plus channels renders CaEuCAM a highly selective adsorbent for methylene blue (MB) due to a synergy of electrostatic affinity, ion-dipole interaction, and size matching. Of note is the reusability of CaEuCAM toward Fe3+/3-NP sensing and MB adsorption besides its fast response. These findings could be very useful in guiding the development of multifunctional Ln-MOFs for sensing and adsorption applications in water media.

Development of a dispersive micro solid phase extraction-HPLC method for the simultaneous quantification of antiepileptic drugs in various matrices

Due to the widespread utilization of antiepileptic drugs for seizure control and patient well-being, it is crucial to determine their presence in biological and water samples. This is essential for optimizing therapy, comprehending drug behavior, identifying drug interactions, monitoring environmental contamination, and safeguarding public health and ecology. Hence, a novel method that combines dispersive micro solid phase extraction with HPLC-DAD was developed to simultaneously determine the presence of Lacosamide, Levetiracetam, and Phenytoin. To achieve this, a new sorbent was synthesized using the hydrothermal and sol–gel methods, which consisted of bimetallic MIL-100 (Fe, Ni) on MIL-100 (Mn), SiO2, and Fe3O4 nanoparticles. We compared the extraction capabilities of several sorbents in order to select the most effective one. The optimal ratio of components for the chosen sorbent was determined through the simplex lattice design to enhance its efficiency. The optimized values for SiO2, Fe3O4, and MIL-100 (Fe, Ni) on MIL-100 (Mn) were found to be 0.1, 0.34, and 0.56, respectively. The parameters that affected the dispersive micro solid phase extraction method were optimized using both experimental design and one factor at a time. Under the optimal conditions, the linear range for the detection of Lacosamide, Levetiracetam, and Phenytoin was determined to be 0.1–363.0, 0.3–372.0, and 0.4–435.0 ng mL−1, respectively, with low LODs below 0.13 ng mL−1. Additionally, a preconcentration factor of 492.6, 487.1, and 469.5 was achieved for measuring Lacosamide, Levetiracetam, and Phenytoin, respectively. The intra-day and inter-day relative standard deviations (RSDs) ranged from 3.8 % to 4.6 % and 4.2 % to 5.2 %, respectively. The recoveries and RSDs for analyzing real water, human urine, and serum samples were found to be between 89.6–97.0 % and 4.53–6.44 %, respectively.