A nanofiber mat prepared from sulfonated polyaniline for solid-phase extraction of fluoroquinolones from water and biological fluids prior to their quantitation by UPLC-MS/MS

Development of a Sensitive Monoclonal Antibody-Based Colloidal Gold Immunochromatographic Strip for Lomefloxacin Detection in Meat Products

Lomefloxacin (LOM), an antibiotic crucial for preventing various animal diseases in animal husbandry, can pose serious health risks when found in excessive amounts in meat products. The development of highly specific and sensitive colloidal gold immunochromatographic test strips is essential for the accurate detection of this class of antibiotics. Our study utilized a monoclonal antibody (mAb) assay and immunochromatographic strips to detect lomefloxacin residues in meat products. The results showed minimal cross-reactivity with other structural analogs, with a maximum half inhibitory concentration (IC50) of 0.93 ng/mL and a linear range of 0.38 to 2.3 ng/mL for the indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). The recovery of LOM was 80% to 120%, with an average coefficient of variation below 5%. The immunochromatographic strip test results showed a visual detection limit of 2.5 ng/g, meeting the market requirements for the test. This study highlights the significance of specific and sensitive testing methods for detecting lomefloxacin, ensuring consumers' safety and health.

Comparison of ZrO2 Particles and Polyaniline as Additives in Polystyrene-Based Sorbents for the Micro-Solid Phase Extraction of Psychoactive Drugs from Biofluids

The intensive development of extraction methods based on μ-SPE extraction contributes to the increased interest in the synthesis of new sorption materials. This work presents the characterization of polystyrene fibers and polystyrene fibers blended with ZrO2 particles or polyaniline obtained by electrospinning and their use in the extraction of selected psychoactive drugs from biological samples. The characteristic of produced fibers is made by performing SEM images, measuring average fiber diameter, and examining their sorption abilities. Among the fibers based on pure polystyrene, tested in the first stage, the best sorption properties are demonstrated for the fibers obtained from a polystyrene solution in DMF with a concentration of 17.5 wt%. In the next stage, this material was modified with synthesized ZrO2 particles and polyaniline. Among the tested materials, the sorbent based on polystyrene with polyaniline shows the best sorption properties of the tested substances. The use of this material in the μ-SPE in a needle enables the extraction of selected compounds from aqueous and biological samples such as urine and human plasma.

Miniaturized centrifugation accelerated pipette-tip matrix solid-phase dispersion based on poly(deep eutectic solvents) surface imprinted graphene oxide composite adsorbent for rapid extraction of anti-adipogenesis markers from Solidago decurrens Lour

Overweight and obesity are the causes of many diseases and have become global "epidemics". Research on natural active components with anti-adipogenesis effects in plants has aroused the interest of researchers. One of the most critical problems is establishing sample preparation and analytical techniques for quickly and selectively extracting and determining the active anti-adipogenesis components in complex plant matrices for developing new anti-adipogenic drugs. In this study, a new poly(deep eutectic solvents) surface imprinted graphene oxide composite (PDESs-MIP/GO) with high selectivity for phenolic acids was prepared using deep eutectic solvents as monomers and crosslinkers. A miniaturized centrifugation-accelerated pipette-tip matrix solid-phase dispersion method (CPT-MSPD) with PDESs-MIP/GO as adsorbent, coupled with high-performance liquid chromatography, was further developed for the rapid determination of anti-adipogenesis markers in Solidago decurrens Lour. (SDL). The established method was successfully used to determination anti-adipogenesis markers in SDL from different regions, with the advantages of accuracy (recoveries: 94.4 - 115.9 %, RSDs ≤ 9.8 %), speed (CPT-MSPD time: 11 min), selectivity (imprinting factor: ∼2.0), and economy (2 mg of adsorbent and 1 mL of solvents), which is in line with the current advanced principle of "3S+2A" in analytical chemistry.

Visual fluorescence detection of ciprofloxacin by Zn-metal-organic framework@nanocellulose transparent films based on aggregation-induced emission

The invention and production of Ciprofloxacin (CIP) have a positive impact on medical treatment, but the overuse of CIP is also harmful to the environment. In this paper, we prepared a novel film material for detection of CIP by in situ synthesis of zinc-based metal-organic framework (Zn-BDC) on TEMPO-oxidized cellulose nanofibers (TOCNF). The nanoscale Zn-BDC were uniformly distributed on the TOCNF that was beneficial to realize the transparency and functionality of Zn-BDC@TOCNF whose transparency was up to 87 %. Zn-BDC@TOCNF showed no fluorescence itself while showed bright fluorescence upon the contact of CIP, which was proposed as the aggregation-induced emission (AIE) of CIP that defused and assembled in the Zn-BDC@TOCNF. There was a certain linear relationship between fluorescence intensity and concentration of CIP (R2 = 0.994, LOD = 0.083 μM). In the detection process, CIP could still fluoresce in Zn-BDC@TOCNF even if it was interfered by other ions and small biological molecules, and the weak acid environment was conducive to AIE of CIP. Generally, it was of great significance to establish a rapid and effective monitoring mechanism for CIP in water for environmental protection and ecological balance.

Polyaniline and Polyaniline-Based Materials as Sorbents in Solid-Phase Extraction Techniques

Polyaniline (PANI) is one of the best known and widely studied conducting polymers with multiple applications and unique physicochemical properties. Due to its porous structure and relatively high surface area as well as the affinity toward many analytes related to the ability to establish different types of interactions, PANI has a great potential as a sorbent in sample pretreatment before instrumental analyses. This study provides an overview of the applications of polyaniline and polyaniline composites as sorbents in sample preparation techniques based on solid-phase extraction, including conventional solid-phase extraction (SPE) and its modifications, solid-phase microextraction (SPME), dispersive solid-phase extraction (dSPE), magnetic solid-phase extraction (MSPE) and stir-bar sorptive extraction (SBSE). The utility of PANI-based sorbents in chromatography was also summarized. It has been shown that polyaniline is willingly combined with other components and PANI-based materials may be formed in a variety of shapes. Polyaniline alone and PANI-based composites were successfully applied for sample preparation before determination of various analytes, both metal ions and organic compounds, in different matrices such as environmental samples, food, human plasma, urine, and blood.

The Ultratrace Determination of Fluoroquinolones in River Water Samples by an Online Solid-Phase Extraction Method Using a Molecularly Imprinted Polymer as a Selective Sorbent

Fluoroquinolones (FQs) are broad-spectrum antibiotics widely used to treat animal and human infections. The use of FQs in these activities has increased the presence of antibiotics in wastewater and food, triggering antimicrobial resistance, which has severe consequences for human health. The detection of antibiotics residues in water and food samples has attracted much attention. Herein, we report the development of a highly sensitive online solid-phase extraction methodology based on a selective molecularly imprinted polymer (MIP) and fluorescent detection (HPLC-FLD) for the determination of FQs in water at low ng L−1 level concentration. Under the optimal conditions, good linearity was obtained ranging from 0.7 to 666 ng L−1 for 7 FQs, achieving limits of detection (LOD) in the low ng L−1 level and excellent precision. Recoveries ranged between 54 and 118% (RSD < 17%) for all the FQs tested. The method was applied to determining FQs in river water. These results demonstrated that the developed method is highly sensitive and selective.

Use of hydroxypropyl β-cyclodextrin hybrid monolithic material as adsorbent for dispersive solid-phase extraction of fluoroquinolones from environmental water samples

In this study, the hydroxypropyl β-cyclodextrin hybrid monolithic material was fabricated and firstly applied as adsorbent for dispersive solid-phase extraction coupled with high-performance liquid chromatography to detect trace-level seven fluoroquinolones in water samples. The prepared hydroxypropyl β-cyclodextrin hybrid monolithic material was characterized by fourier transform infrared spectroscopy, scanning electron microscopy and adsorption experiments, which showed excellent specific adsorption to the target fluoroquinolones. Under the optimized conditions, the extraction methodology showed satisfactory precision with relative standard deviations between 2.6 and 5.6%, good linearity (R² ≥0.9990) and satisfactory recoveries (82.5∼91.8%). The limits of detection and limits of quantification of the method were in the range of 0.4∼1.2 ng mL^-1 and 1.4∼4.0 ng mL^-1 respectively, which confirmed the possibility of quantifying trace levels. Furthermore, the material could be reused at least five times. These results demonstrated that the hydroxypropyl β-cyclodextrin hybrid monolithic material was a promising adsorbent for fluoroquinolones, and the established method combined dispersive solid-phase extraction with high-performance liquid chromatography was suitable for the determination of fluoroquinolones in aqueous samples. This article is protected by copyright. All rights reserved.

Polystyrene nanofibers as an effective sorbent for the adsorption of clonazepam: kinetic and thermodynamic studies

Polystyrene (PS) electrospun nanofibers were prepared via electrospinning for the adsorption of clonazepam from aqueous solution. The adsorption conditions such as adsorption time, solution pH and the amount of adsorbent were optimized. The adsorption kinetics and thermodynamic properties of clonazepam on PS nanofibers were studied under optimized conditions. The pseudo-second-order kinetic model can fit well the adsorption process of clonazepam on polystyrene nanofibers, indicating that the diffusion process in the fiber is the rate-limiting step of the adsorption process. The adsorption equilibrium data are in accordance with the Freundlich isotherm model, and the maximum adsorption capacity is 3.2 mg g⁻¹. Thermodynamic studies revealed that the adsorption process is endothermic and spontaneous in nature. It was suggested that PS electrospun nanofibers have good potential for the separation and purification of clonazepam from a water-soluble matrix as a novel effective adsorbent material.

Polystyrene (PS) electrospun nanofibers were prepared via electrospinning for the adsorption of clonazepam from aqueous solution.

Preparation of molecularly imprinted resin/polydopamine nanofibers mat for the highly efficient extraction and determination of sulfonamides in environmental water

With polyacrylonitrile nanofibers mat (PAN NFsM) as a template, molecularly imprinted resin/polydopamine nanofibers mat (MIR/PDA NFsM) was synthesized for the extraction of sulfonamides (SAs) in water. The specific surface area and pore volume were increased obviously due to the functionalization of MIR. The adsorption efficiencies of MIR/PDA NFsM under optimized conditions for SAs were 92.3-99.3%. Possible adsorption mechanisms of imprinting recognition and hydrogen bond interactions were also put forward. Compared with MIR particles, the MIR/PDA NFsM exhibited much superior adsorption performance. Particularly, the outstanding mass transfer efficiency of MIR/PDA NFsM was much higher than the other reported adsorbents for SAs. Finally, a new method based on the solid-phase extraction (SPE) of MIR/PDA NFsM was successfully developed for the detection of five SAs in environmental water with HPLC-MS/MS and applied to the analysis of actual samples. Under the selected conditions, the enrichment factors of MIR/PDA NFsM of SCP, SMT, SMZ, SMR, and SMX were between 23.0 and 25.0. Low detection limits (0.26-0.76 ng L^-1), broad linear range (1.0 ng L^-1 to 10.0 μg L^-1), and satisfactory recoveries (82.8-115.6%) and precisions (RSDs < 7.2%) were obtained. Moreover, the excellent reusability properties and storage stability endowed MIR/PDA NFsM with great value for practical applications.

A novel electrochemiluminescence immunosensing strategy fabricated by Co(OH)2 two-dimensional nanosheets and Ru@SiO2-Au NPs for the highly sensitive detection of enrofloxacin

In this work, a novel sensitive electrochemiluminescence immunosensor based on Ru@SiO₂-Au NPs and Co(OH)₂ two-dimensional nanosheets (2D Co(OH)₂) is constructed for the detection of enrofloxacin (ENR). Ruthenium bipyridine silica spheres and modified gold nanoparticles were synthesized as immune probe materials, which were combined with ENR antibodies (Abs) to form the immune probe part. 2D Co(OH)₂ with a large specific surface area and good catalytic effect was firstly used as an immune substrate material, and at the same time, it was conjugated with the coating antigen (Ae) of ENR to form an immune substrate. Based on the principle of competitive immunity, ENR and ENR coated antigen could jointly compete for the specific binding sites on the ENR antibody, so as to achieve efficient detection of ENR. Under optimal conditions, the prepared immunosensor exhibited high sensitivity with a wide linear range from 0.0001 to 1000 ng mL^-1 and a low detection limit (LOD) of 0.063 pg mL^-1. The proposed immunosensor has been successfully applied to the detection of ENR residues in poultry, aquatic products and lake water.

A photoelectrochemical aptasensor of ciprofloxacin based on Bi24O31Cl10/BiOCl heterojunction

A photoelectrochemical (PEC) aptasensor was designed and constructed by Bi₂₄O₃₁Cl₁₀/BiOCl heterojunction as a photoelectric active material for realizing the determination of trace ciprofloxacin (CIP) in water. Compared with Bi₂₄O₃₁Cl₁₀, Bi₂₄O₃₁Cl₁₀/BiOCl heterojunction possessed the improvement of light harvesting and the enhancement of photocurrent signal. The formation of heterojunction between Bi₂₄O₃₁Cl₁₀ and BiOCl can accelerate the transportation efficiency and inhibit the recombination rate of photoinduced carriers. Based on the excellent PEC performance, CIP aptamer was introduced on the modified Bi₂₄O₃₁Cl₁₀/BiOCl/indium tin oxide (ITO) electrode for fabricating a PEC aptasensor. Owing to the combination between aptamer and CIP, CIP-aptamer complex can block the transfer of charge, leading to the reduction of photocurrent response. The PEC aptasensor possessed high sensitivity with a wide detection range (5.0~1.0 × 10⁴ ng L^-1) and a low detection limit (1.67 ng L^-1, S/N = 3). The PEC aptasensor with good selectivity and reproducibility has been applied to the determination of CIP in water.

Selective extraction and enhanced-sensitivity detection of fluoroquinolones in swine body fluids by liquid chromatography-high resolution mass spectrometry: Application in long-term monitoring in livestock

To ensure food safety in livestock industries, developing a non-lethal and cost-effective detection method for the long-term monitoring of veterinary antibiotics in animals will be beneficial to avoid unnecessary losses. In this study, a highly-selective extraction using dispersive micro solid-phase extraction method coupled with an enhanced-sensitivity detection by pre-column dilution injection and liquid chromatography-high resolution mass spectrometry was used to determine the restricted fluoroquinolones (FQs) in swine body fluids. The proposed method showed good linear coefficients higher than 0.999, and high sensitivity with the LODs and LOQs in the range of 0.02-0.03 μg/L and 0.06-0.1 μg/L in swine body fluids, respectively. For further evaluation, the adequate recoveries (85.3-112.8%), satisfactory repeatability (intra-day and inter-day precisions of 2.1%-8.2% and 3.8%-13.7%, respectively), and acceptable matrix effect (0.92-1.12) of the FQs were achieved. It has been successfully applied for analysis of the FQs in body fluids without sacrificing animals in the future.

Deep eutectic solvent functionalized graphene oxide composite adsorbent for miniaturized pipette-tip solid-phase extraction of toluene and xylene exposure biomarkers in urine prior to their determination with HPLC-UV

A deep eutectic solvent functionalized graphene oxide composite adsorbent (DFG) was synthesized through reversible-addition fragmentation chain-transfer polymerization. The synthesized DFG had multiple adsorption interactions after covalent modification with a deep eutectic solvent (allyltriethylammonium bromide/ethylene glycol). Adsorption isotherms and kinetics studies of DFG indicate that the adsorption of hippuric acid (HA) and methylhippuric acid (MHA) was monolayer chemical adsorption. The comparison of DFG with commercial adsorbents demonstrates that the adsorption ability of DFG was superior. This was due to the multiple adsorption interactions of DFG for the three analytes (mainly π-interaction, hydrogen bonding, electrostatic adsorption, and hydrophobic interaction). The DFG adsorbent was applied to miniaturized pipette-tip solid-phase extraction (MPT-SPE), followed by high-performance liquid chromatography (HPLC) to determine biomarkers in urine for toluene and xylene exposure. The DFG-MPT-SPE-HPLC method required only 2.00 mg of DFG as adsorbent, 0.50 mL of washing solvent, and 0.40 mL of elution solvent to achieve a wide linear range (0.200-200 μg mL^-1), high recoveries (90.9-99.1%), and high precision (RSD ≤ 6.3%). The proposed method was applied to determine HA and MHA in urine samples from occupational workers. Graphical abstract Deep eutectic solvent functionalized graphene oxide composite adsorbent for miniaturized pipette-tip solid-phase extraction of toluene and xylene exposure biomarkers in urine prior to their determination with HPLC-UV.

Immobilized imidazolium-based ionic liquids in C18 for solid-phase extraction

In this work, two solid-phases based on imidazolium-based ionic liquids were obtained and characterized for solid-phase extraction of fluoroquinolones. The process of immobilization was performed replacing a toxic reagent by UV-irradiation to get a harmless process. The obtained solid-phases were characterized by nuclear magnetic resonance spectroscopy and elemental analysis. Each solid-phase was packed in a cartridge and was used in solid-phase extraction processes for norfloxacin and ciprofloxacin, after the optimization of some parameters such as the elution solvent, the eluent volume and, the sample volume to be used during the loading step. The developed solid-phases with immobilized ionic liquids were successfully implemented for the studied compounds and indicate high probabilities to be useful in solid-phase extractions of other fluoroquinolones.