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Herein, 2-mercapto-5-benzimidazolesulfonate acid sodium salt dihydrate (MBZS)-protected gold-silver bimetallic nanoclusters, named MBZS-AuAg NCs, were synthesized. Interestingly, we found that MBZS-AuAg NCs solutions can exhibit different fluorescence color changes under sulfide stimulation. A series of modern analytical testing techniques were used to explore the interaction mechanism between MBZS-AuAg NCs and sulfide. Sulfide ions can not only cause MBZS-AuAg NCs to exhibit rich fluorescence color changes similar to those of a chameleon but also have four linear relationships between the response intensity and sulfide concentration. A wide-range sulfide fluorescence sensing platform was constructed based on four linear segments with different fluorescence color responses. This sensing platform can be directly used for the determination of S2- with a detection limit as low as 11 nM. The portable test paper based on MBZS-AuAg NCs can realize the visual and rapid detection of gaseous hydrogen sulfide with a detection limit of 100 ppb (v/v). The wide detection range of the proposed method not only allows it to be used as an alternative method for sulfide detection in environmental samples but also has potential applications in the rapid detection and early warning of hydrogen sulfide gas in industrial and mining scenarios.
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The design of single-atom nanozymes with dual active sites to increase their activity and for the detection and degradation of contaminants is rare and challenging. In this work, a single-atom nanozyme (FeCu-NC) based on a three-dimensional porous Fe/Cu dual active site was developed as a colorimetric sensor for both the quantitative analysis of isoniazid (INH) and the efficient degradation of levofloxacin (LEV). FeCu-NC was synthesized using a salt template and freeze-drying method with a three-dimensional hollow porous structure and dual active sites (Fe-Nx and Cu-Nx). In terms of morphology and structure, FeCu-NC exhibits excellent peroxidase-like activity and catalytic properties. Therefore, a colorimetric sensor was constructed around FeCu-NC for sensitive and rapid quantitative analysis of INH with a linear range of 0.9-10 µM and a detection limit as low as 0.3 µM, and the sensor was successfully applied to the analysis of INH in human urine. In addition, FeCu-NC promoted the efficient degradation of LEV by peroxymonosulfate activation, with a degradation rate of 90.4% for LEV at 30 min. This work sheds new light on the application of single-atom nanozymes to antibiotics for colorimetric sensing and degradation.
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Cobre , Hierro , Isoniazida , Levofloxacino , Isoniazida/química , Isoniazida/análisis , Levofloxacino/orina , Levofloxacino/análisis , Levofloxacino/química , Hierro/química , Cobre/química , Humanos , Peroxidasa/química , Peroxidasa/metabolismo , Colorimetría/métodos , Nanoestructuras/química , CatálisisRESUMEN
The process of thiocyanation is a notable chemical conversion owing to the extensive range of applications associated with thiocyanate compounds in the field of organic chemistry. In past centuries, the thiocyanation reaction incorporated metal thiocyanates or thiocyanate salts as sources of thiocyanate, which are environmentally detrimental and undesirable. In recent literature, there have been numerous instances where combined or indirect alternative sources of thiocyanate have been employed as agents for thiocyanation, showcasing their noteworthy applications. The present literature review focuses on elucidating the ramifications associated with the utilization of indirect or combined alternative sources of thiocyanate in various thiocyanation reactions.
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For a long time, the detection of nitroimidazole antibiotics (NIABs) has been a research focus in environmental analytical chemistry. In this work, a novel technique for the analysis of nitroimidazoles was established based on capillary electrophoresis (CE). UiO-66, synthesized using a solvothermal method, was utilized as an adsorbent in the dispersive solid-phase extraction (DSPE) of five different NIABs. The separation and detection of NIABs in environmental water samples were accomplished using the CE diode array detection method. The optimal extraction conditions were obtained after systematically studying the effects of adsorption time, the amount of extractant, and elution solvent on extraction efficiency. According to the results of the study, the limit of detections of the five NIABs were between 16 and 97 ng/mL, the relative standard deviations were between 0.32% and 0.55%, and the spike recoveries were between 87.43% and 104.8%. This study presents a novel technique for measuring NIABs in complex water samples.
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Nitroimidazoles , Contaminantes Químicos del Agua , Antibacterianos/análisis , Nitroimidazoles/análisis , Contaminantes Químicos del Agua/análisis , Electroforesis Capilar/métodos , Extracción en Fase Sólida/métodos , Agua , Cromatografía Líquida de Alta PresiónRESUMEN
Inspired by natural enzymes, artificial enzymes have been widely studied due to their ease of mass production, robustness to harsh environments and high stability. In this work, a peptide nanotube/hemin composite (KL@hemin) as an artificial enzyme was prepared by immobilizing hemin onto self-assembled peptide nanotubes (PNTs). The successful loading of hemin was determined by a series of characterizations. The multiple noncovalent interactions between the PNTs and hemin endow KL@hemin with strong stability. Subsequent enzyme activity tests showed that the prepared KL@hemin exhibited enhanced peroxidase activity. Further experiments indicate that PNTs as carriers can not only protect hemin from dimerization to maintainenzyme activity but also increase the affinity of hemin to the substrate for faster binding and accelerate mass transfer, thus promoting the whole catalytic process. Coupled with a peroxidase-catalyzed chromogenic system, a colorimetric method for dopamine detection was constructed based on KL@hemin. The strategy shows high sensitivity and selectivity and has been applied to the determination of dopamine in dopamine injection and meat samples.
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Hemina , Nanotubos de Péptidos , Hemina/química , Peroxidasa/química , Dopamina , Peroxidasas , Colorimetría/métodos , Colorantes/químicaRESUMEN
Due to the widespread use of dinotefuran around the world, its impact on food and environmental safety has aroused great concern, and the establishment of a rapid and convenient approach for dinotefuran detection is necessary but challenging. Herein, we synthesized a unique three-dimensional framework {[(CH3)2NH2]2[Cd3(BCP)2]·10H2O·3.5DMF}n (1). Single-crystal X-ray analysis indicates that 1 possesses a 4,8-connected anion framework that corresponds to alb topology, with a one-dimensional rectangular channel along the c-axis with the size of 4 Å × 10 Å. Compound 1 displays satisfactory solvent and thermal stability. Luminescent investigations reveal that 1 can selectively detect dinotefuran by fluorescence quenching among other pesticides, displaying excellent anti-interference performance with common ions in water. Importantly, the limit of detection is as low as 2.09 ppm, which is far below the residual concentration of the U.S. food standard. A fluorescence quenching mechanism study shows that there exists competitive energy absorption and static quenching processes. To our knowledge, 1 is the first MOF-based fluorescence probe for dinotefuran detection.
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Luminiscencia , Estructuras Metalorgánicas , Cadmio , Guanidinas , Neonicotinoides , Nitrocompuestos , AguaRESUMEN
A novel 3D metal-organic framework (MOF){[Tb3(CBA)2(HCOO)(µ3-OH)4(H2O)]·2H2O·0.5DMF} n (S-1) was synthesized by the solvothermal method. The crystal structure indicates that [Tb4O4] cubane clusters self-assemble into an infinite chain by sharing vertex, which is further linked to adjacent chains through 1,1-cyclobutanedicarboxylic acid ligand (H2CBA), resulting in a honeycomb arrayed framework. S-1 possesses excellent water stability and still retains intact structure after exposure to water for 10 weeks or boiling water for 10 weeks. Interestingly, S-1 acts as a luminescence sensor to selectively and sensitively detect quercetin with the limit of detection (LOD) as low as 0.23 ppm (7.6 × 10-7 M). The relationship between relative luminescence intensity and concentration obeys linear in the range of 0-300 ppm (0-993 µM), which allows quantitative detection of quercetin. Importantly, S-1 can be reused at least six times with almost no change in luminescent intensity. Compared with the high performance liquid chromatography-mass spectrometry (HPLC-MS) method, S-1 was used to determine the content of quercetin in onionskin and apple peel samples with satisfactory results. Furthermore, a portable S-1 test paper is also developed and expected to be applied in practice. To our knowledge, S-1 is the first example of MOFs as luminescent sensor for quercetin.
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Sustancias Luminiscentes/química , Estructuras Metalorgánicas/química , Quercetina/análisis , Equipo Reutilizado , Límite de Detección , Sustancias Luminiscentes/síntesis química , Mediciones Luminiscentes/instrumentación , Mediciones Luminiscentes/métodos , Malus/química , Estructuras Metalorgánicas/síntesis química , Cebollas/química , Papel , Terbio/químicaRESUMEN
Recently, water-soluble gold nanoclusters (AuNCs) have attracted more and more attention due to their unique properties. In this study, penicillamine-protected gold nanoclusters (Pen-AuNCs) were synthesized and initially fractionated by sequential size-selective precipitation (SSSP). The crude Pen-AuNCs and SSSP fractions were separated by capillary zone electrophoresis (CZE) with a diode array detector. The effects of key parameters, including the concentration of phosphate buffer, pH value and the ethanol content were systematically investigated. The separation of water-soluble poly-disperse AuNCs were well achieved at 30 mM phosphate buffer with 7.5% EtOH, pH 12.0, and applied voltage of 15 kV. The linear correlation between AuNCs diameter and mobility was observed. This finding provides an important reference for CE separation and product purification of water-soluble AuNCs or other nanomaterials.
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Electroforesis Capilar/métodos , Oro , Nanopartículas del Metal/análisis , Tampones (Química) , Concentración de Iones de Hidrógeno , Tamaño de la Partícula , Penicilamina/química , Solubilidad , AguaRESUMEN
Strong fluorescent carbon nanodots (FCNs) were synthesized with a green approach using gardenia as a carbon source through a one-step hydrothermal method. FCNs were characterized by their UV-vis absorption spectra, photoluminescence (PL), Fourier transform infrared spectroscopy (FTIR) as well as X-ray photoelectron spectroscopy (XPS). We further explored the use of as-synthesized FCNs as an effective probe for the detection of metronidazole (MNZ), which is based on MNZ-induced fluorescence quenching of FCNs. The proposed method displayed a wide linear range from 0.8 to 225.0 µM with a correlation coefficient of 0.9992 and a limit of detection as low as 279 nM. It was successfully applied to the determination of MNZ in commercial tablets and rabbit plasma with excellent sensitivity and selectivity, which indicates its potential applications in clinical analysis and biologically related studies.
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Gardenia , Animales , Carbono , Colorantes Fluorescentes , Metronidazol , Preparaciones Farmacéuticas , Espectroscopía de Fotoelectrones , ConejosRESUMEN
A novel isocratic RP-HPLC method with UV photodiode array detection for the determination of seven organic acids in vinegar samples was developed and optimized. Samples were analyzed on a C18 (150 × 4.6 mm id, 5 µm) analytical column. Methanol-0.010 M sodium dihydrogen phosphate buffer adjusted with H3PO4 to pH 2.80 (2 + 98, v/v), was used as the mobile phase. The column oven temperature was optimized at 23.0°C, the flow rate was 0.80 mL/min, and the detection wavelength was 210 nm. Matrix-matched calibration curves were prepared for all analytes, and the correlation coefficients were greater than 0.99. LOD and LOQ ranged from 0.10 to 10.0 and 0.30 to 30.0 µg/mL, respectively. The results for interday and intraday precision and accuracy fell within the ranges specified. Vinegar samples were quantified by the standard addition method. The main advantages of this method are its selectivity, which is one of the main weaknesses of most methods when determining organic acids in complex matrixes, and its simplicity since little sample preparation is needed. Moreover, it is safe and inexpensive with low organic solvent usage.
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Ácido Acético/química , Cromatografía Liquida/métodos , Análisis de los Alimentos/métodos , Concentración de Iones de Hidrógeno , Reproducibilidad de los Resultados , TemperaturaRESUMEN
This paper proposes a novel strategy to enhance detection of doxorubicin in human plasma, using homemade CE combined with normal stacking mode (NSM). The detection system of CE named as in-column tapered optic-fiber light-emitting diode induced fluorescence detection system is economic and more sensitive that has been demonstrated in our previous work. The influence of sample matrix, BGE, applied voltage, and injection time on the efficiency of NSM were systematically investigated. The clean extracts were subjected to CE separation with optimal experimental conditions: Ethanol-water (1:1, v/v) was used as sample matrix, pH 4.12 15 mM sodium phosphate buffer solution containing 70% v/v ACN, applied voltage 23 kV and 45 s hydrodynamic injection at a height of 20 cm. The detection system displayed linear dynamic range from 6.4 to 1.13 × 10(3) ng/mL with a correlation coefficient of 0.9990 and LOD 2.2 ng/mL for doxorubicin (DOX). The proposed CE method has been successfully applied to determine DOX in human plasma which the recoveries of standard DOX added to human plasma were found to been the range of 93.8-104.6%. The results obtained demonstrate that our detection system combined with NSM is a good idea to enhance sensitivity in CE for routine determination of DOX in some biological specimens.
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Doxorrubicina/sangre , Electroforesis Capilar/métodos , Espectrometría de Fluorescencia/instrumentación , Espectrometría de Fluorescencia/métodos , Tampones (Química) , Diseño de Equipo , Etanol , Humanos , Fibras Ópticas , Reproducibilidad de los ResultadosRESUMEN
Sulfonamide antibiotics (SAs) have been widely used as antibacterial drugs for the prevention and treatment of livestock and poultry diseases, but they seriously threaten human health because they can accumulate in humans. Therefore, it is highly important to develop methods for monitoring sulfonamide residues in aquaculture and food. In this research, based on the generation of porous carbon (PC) by the pyrolysis of sodium citrate, magnetic porous carbon (PC@Fe3O4) was synthesized by a solvothermal method and used as an adsorbent for the magnetic solid-phase extraction of SAs. The effects of the proportion of PC in PC@Fe3O4, adsorbent dosage, adsorption time, eluent type, extraction pH, salt concentration and eluent dosage on the extraction efficiency were systematically studied. The adsorption performance and behavior of PC@Fe3O4 on SAs were evaluated using adsorption kinetics and adsorption isotherms, and the adsorption mechanism was preliminarily discussed. Under optimal conditions, combined with capillary electrophoresis diode array detection, a sensitive detection method for SAs was developed. The proposed method can be used for the determination of six SAs in fishpond water and milk samples, with a linear range of 0.5-200 ng mL-1, detection limits of 0.24-0.34 ng mL-1, and spiked recoveries of 85.9-109.0 %.
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Antibacterianos , Carbono , Electroforesis Capilar , Límite de Detección , Leche , Extracción en Fase Sólida , Sulfonamidas , Extracción en Fase Sólida/métodos , Electroforesis Capilar/métodos , Sulfonamidas/análisis , Sulfonamidas/aislamiento & purificación , Sulfonamidas/química , Adsorción , Porosidad , Carbono/química , Antibacterianos/análisis , Antibacterianos/aislamiento & purificación , Antibacterianos/química , Leche/química , Animales , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/aislamiento & purificación , Contaminantes Químicos del Agua/químicaRESUMEN
Mercury ions (Hg2+) and sulfur ions (S2-), have caused serious harm to the ecological environment and human health as two kinds of highly toxic pollutants widely used. Therefore, the visual quantitative determination of Hg2+ and S2- is of great significance in the field of environmental monitoring and medical therapy. In this study, a novel fluorescent "on-off-on" peptide-based probe DNC was designed and synthesized using dipeptide (Asn-Cys-NH2) as the raw material via solid phase peptide synthesis (SPPS) technology with Fmoc chemistry. DNC displayed high selectivity in the recognition of Hg2+, and formed non-fluorescence complex (DNC-Hg2+) through 2:1 binding mode. Notably, DNC-Hg2+ complex generated in situ was used as relay response probe for highly selective sequential detection of S2- through reversible formation-separation. DNC achieved highly sensitive detection of Hg2+ and S2- with the detection limits (LODs) of 8.4 nM and 5.5 nM, respectively. Meanwhile, DNC demonstrated feasibility for Hg2+ and S2- detections in two water samples, and the considerable recovery rate was obtained. More importantly, DNC showed excellent water solubility and low toxicity, and was successfully used for consecutive discerning Hg2+ and S2- in test strips, living cells and zebrafish larvae. As an effective visual analysis method in the field, smartphone RGB Color Picker APP realized semi-quantitative detections of Hg2+ and S2- without the need for complicated device.
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Colorantes Fluorescentes , Mercurio , Péptidos , Pez Cebra , Mercurio/análisis , Animales , Colorantes Fluorescentes/química , Colorantes Fluorescentes/síntesis química , Humanos , Péptidos/química , Péptidos/análisis , Espectrometría de Fluorescencia , Límite de Detección , Azufre/química , Azufre/análisis , Contaminantes Químicos del Agua/análisis , Imagen Óptica , Células HeLa , Iones/análisisRESUMEN
BACKGROUND: Due to the unavoidable use of cerium in daily life, the accumulation of cerium in the environment increases health risks for humans. Therefore, it is crucial to develop a chemical sensing technology for the rapid, sensitive, and selective detection of cerium ions. RESULTS: In this research work, a novel two-dimensional chain structure of a europium-based metal organic framework (Eu-MOF) [Eu2(tcpa)(Htcpa)2] was synthesized by using 3,4,5,6-tetrachloro-1,2-benzenedicarboxylic acid (H2TCPA) as the ligand and europium nitrate as the metal source. The results of powder X-ray diffraction and thermogravimetric analysis show that the synthesized Eu-MOF has excellent chemical and thermal stability. When the Eu-MOF suspension was excited by ultraviolet light at 292 nm, four fluorescence emissions were observed at 420, 595, 620 and 705 nm. It was particularly interesting that when cerium ions (Ce3+/Ce4+) were added to the Eu-MOF suspension, the fluorescence intensity at 420 nm was enhanced, while the fluorescence at 620 nm was quenched. On this basis, a ratiometric fluorescent sensor for detecting cerium ions was constructed, which has a good linear relationship in the range of 0.05-15 µM and a detection limit of 16 nM. The plausible mechanism of the change in the fluorescence characteristics of Eu-MOF caused by cerium ions was discussed in detail. Through the study of fluorescence lifetime and ultraviolet absorption, it was proven that the mechanism of Ce3+-quenching Eu-MOF fluorescence is the inner filter effect. Photoinduced electron transfer and internal filtering effects lead to fluorescence quenching at 620 nm, while redox reactions lead to fluorescence enhancement of the ligand at 420 nm. SIGNIFICANCE: The proposed ratiometric fluorescence sensor was successfully employed for the detection of cerium ions in real water samples, confirming that it can be used as an alternative method for the detection of Ce3+ and Ce4+ in environmental samples.
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The isolation of circulating tumor cells (CTCs) from whole blood is a challenging task. Although various studies on the separation of CTCs by acoustofluidic devices have been reported, difficulties still persist, such as the complicated equipment, high cost, and difficult operation. Those problems should be resolved urgently. Herein, we developed an acoustofluidic chip separation system coupled with an ultrasonic concentrated energy transducer (UCET) system for efficient separation of CTCs. In the separation system, the acoustically sensitive particles were pre-focused by inertial forces of the PDMS chip channel structure. Then, the particles with different sizes were separated by acoustic radiation forces (ARF). In this study, the circulating tumor cells was simulated (CTCs-like particles) by aminated mesoporous acoustically sensitive particles (MSN@AM) encapsulated carboxylate polystyrene microspheres (PS-COOH). Subsequently, efficient CTCs-like particles separation was achieved by the acoustofluidic chip coupling system. This study effectively separated polystyrene microspheres carrying acoustically sensitive particles (MSN@AM@PS-COOH). However, the MSNs agglomerates and PS microspheres without acoustically sensitive particles did not show phenomenon of separation. This method allows to efficiently separate 2 µm MSNs agglomeratesï¼8.0-8.9 µm PS microspheres and 10-10.5 µm MSN@AM@PS-COOH particles. It is demonstrated that the CTCs-like particles show more sensitive response, longer moving distance, and more obvious separation effect at the condition of the low frequency traveling wave sound field (20 kHz from UCET). This system can maintain the same separation with reduced amount of reagents used for cancer detection. It may provide a reliable basis for sorting out CTCs efficiently from the whole blood of cancer patients.
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Técnicas Analíticas Microfluídicas , Células Neoplásicas Circulantes , Humanos , Ultrasonido , Células Neoplásicas Circulantes/patología , Poliestirenos , Transductores , Separación Celular , Línea Celular Tumoral , Técnicas Analíticas Microfluídicas/métodosRESUMEN
Herein, a novel relay peptide-based fluorescent probe DGRK was synthesized via solid phase peptide synthesis (SPPS) technology. DGRK exhibited excellent water-solubility, good stability, remarkably large Stokes shift (230 nm) and high selectivity response to Hg2+ with a non-fluorescence complex DGRK-Hg2+ formation via a 1:1 binding mode. Further studies indicated that the DGRK-Hg2+ complex could act as a secondary probe for rapidly and sequentially detecting S2- based on fluorescent "off-on" response, and without interference from a range of anions. The limit of detection (LOD) for Hg2+ and S2- were calculated to be 33.6 nM and 60.9 nM, respectively. In addition, The reversibility of interaction of confirmed that the continuous and reversible recognition behavior of Hg2+ and S2- by the probe DGRK, and could be cycled more than 5 times. In addition, DGRK could be successfully applied to the fluorescence imaging of Hg2+ and S2- in two living cells based on excellent cells permeability and low cytotoxicity. Meanwhile, DGRK was successfully used to create the low-cost and portable test strips for visual detection and rapid analysis under 365 nm UV lamp, and the test strips combined with a smartphone (RGB color) was successfully applied to the semi-quantitative analysis and monitoring of dynamic changes of Hg2+ levels.
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Colorantes Fluorescentes , Mercurio , Humanos , Colorantes Fluorescentes/análisis , Teléfono Inteligente , Mercurio/análisis , Agua , Péptidos , Espectrometría de FluorescenciaRESUMEN
Herein, a covalent organic framework (COF) was grown on a magnetic metal-organic framework (MOF) by a solvothermal method for the efficient extraction of bisphenols (BPs). The magnetic solid-phase extraction (MSPE) of four bisphenols (bisphenol A, bisphenol B, bisphenol AF and bisphenol C) was carried out without adjusting the pH and salt concentration. When 30 mg Fe3O4@NH2-MIL-88(Fe)@TpPa was used to adsorb for 25 min, 6 mL methanol was used to elute for 20 min, and the extract was detected by high-performance liquid chromatography (HPLC). The proposed method has a low detection limit of 0.011-0.036 ng mL-1, a wide linear range of 0.05-100 ng mL-1, and a correlation coefficient (R2) of 0.9980-0.9998. The intra-day and inter-day precisions are 0.74-2.54% and 1.68-3.72%, respectively. Bisphenol A was determined by applying the proposed method to the determination of actual milk samples. The standard addition experiment showed that the relative recovery of the four bisphenols was 85.70-119.7%. Pseudosecond-order, first-order, Langmuir and Freundlich models were applied to explore the adsorption characteristics of Fe3O4@NH2-MIL-88(Fe)@TpPa. In general, the established Fe3O4@NH2-MIL-88(Fe)@TpPa-MSPE-HPLC-UV method exhibits attractive sensitivity, simple manipulation, and excellent reusability, and it has excellent prospects for the detection of trace BPs in complex milk matrices.
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Leche , Extracción en Fase Sólida , Animales , Cromatografía Líquida de Alta Presión , Leche/química , Extracción en Fase Sólida/métodos , Fenómenos Magnéticos , Límite de DetecciónRESUMEN
The design of nanozymes with high metal atom loading is of great significance to improve enzyme activity and is also the key to furthering the construction of highly sensitive colorimetric sensors. In this work, a colorimetric sensor for the quantitative analysis of tannic acid (TA) was developed based on two-dimensional carbon nanosheet carbon nitride (CN)-supported Cu single-atom nanozymes (Cu/CN). Cu/CN was synthesized by supramolecular preorganization and calcination, with an ultrathin nanosheet structure and a high density of Cu active sites, with a Cu loading of up to 14.3 wt%. Benefiting from the above characteristics, Cu/CN exhibits peroxidase-mimicking activity and excellent catalytic performance. Therefore, a colorimetric sensor was constructed for the fast and sensitive quantitative analysis of TA with good linearity in the range of 0.09-3.2 µM and a low detection limit of 30 nM. Furthermore, the sensor was successfully applied to the analysis of TA in tea samples of different varieties. This work sheds new light on the design of nanozymes with a high density of active sites and the analysis of TA in real environments.
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Colorimetría , Nitrilos , Colorimetría/métodos , Nitrilos/química , Catálisis , Peroxidasas/química , Peróxido de Hidrógeno/análisis , Carbono/químicaRESUMEN
Bisphenol compounds exist widely in the environment and pose potential hazards to the environment and human health, which has aroused widespread concern. Therefore, there is an urgent need for an efficient and sensitive analytical method to enrich and determine trace bisphenols in environmental samples. In this work, magnetic porous carbon (MPC) was synthesized by one-step pyrolysis combined with a solvothermal method for magnetic solid-phase extraction of bisphenols. The structural properties of MPC were characterized by field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and saturation magnetization analysis. Its adsorption properties were evaluated by adsorption kinetics and adsorption isotherm studies. By optimizing the magnetic solid-phase extraction and capillary electrophoresis separation conditions, a capillary electrophoresis separation and detection method for four bisphenols was successfully constructed. The results showed that the detection limits of the proposed method for the four bisphenols were 0.71-1.65 ng/mL, the intra-day and inter-day precisions were 2.27-4.03% and 2.93-4.42%, respectively, and the recoveries were 87.68%-108.0%. In addition, the MPC could be easily recycled and utilized, and even if the magnetic solid-phase extraction was repeated 5 times, the extraction efficiency could still be kept above 75%.
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Carbono , Extracción en Fase Sólida , Humanos , Porosidad , Adsorción , Extracción en Fase Sólida/métodos , Fenómenos Magnéticos , Electroforesis Capilar/métodos , Límite de DetecciónRESUMEN
Substrate materials with high sensitivity and storage stability are crucial for the practical analytical application of surface-enhanced Raman scattering (SERS) techniques. In this work, a SERS-active substrate (Si/Au@Ag/ZIF-67) was fabricated with a metal-organic framework (ZIF-67) on a plasmonic surface (Si/Au@Ag) via self-assembly. The as-prepared material combined the properties of the abundant hotspots of the Au@Ag nanoparticles and the excellent adsorption performance of ZIF-67 for organic molecules. The synergy leads to high sensitivity of the composite substrate with a low detection limit for 4-aminothiophenol (a typical Raman reporter molecule) down to 2.0 × 10-9 M and the analytical enhancement factor (AEF) of the SERS substrate is 3.4 × 106. Moreover, the substrates exhibited good repeatability, high reproducibility, and reliable stability due to the MOF coating. The SERS signal was stable after 60 days of storage at room temperature. Ultimately, the optimal Si/Au@Ag/ZIF-67 was applied as a SERS sensor to analyze thiram, and the results showed a linear concentration range from 10-7 to 10-5 M with good linearity (R2 = 0.9934). The recoveries of thiram in spiked apple juice were in the range of 95.7-102.3%, with relative standard deviations less than 4.3%. These results predict that the proposed SERS substrates may hold great potential for the detection of environmental and food pollution in practical applications.