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Paniagua González, Gema

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2003 - 200952010 - 201962020 - 202416
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Mostrando 1 - 10 de 27
  • Miniatura
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    On-line flow injection molecularly imprinted solid phase extraction for the preconcentration and determination of 1-hydroxypyrene in urine samples
    (Elsevier, 2017-05-01) Serrano, Montserrat; Bartolomé, Mónica; Gañán Aceituno, Judith; Gallego Picó, Alejandrina; Bravo Yagüe, Juan Carlos; Paniagua González, Gema; Garcinuño Martínez, Rosa Mª
    New analytical strategies tend to automation of sample pre-treatment and flow analysis techniques provided a number of enhanced analytical methods allowing high throughput. Flow techniques are usually faster, more robust and more flexible than their batch equivalents. In addition, flow methods use less sample and reagent amounts and reduce analytical costs and waste. A flow injection solid-phase extraction pre-concentration system using a molecularly imprinted polymer (MIP) packed micro-column was developed for the determination of 1-hydroxypyrene in human urine with fluorescence detection. The pre-concentration of 1-hydroxypyrene on the MIP was carried out based on the specific retention of analyte by on-line introducing the sample into the micro-column system. Methanol and dichloromethane mixture was used to elute the retained analyte for fluorometric analysis. Important influencing factors were studied in detail, in batch and in flow (MISPE procedure optimisation, sample and eluent volumes, flow rate, dimensions of MIP micro-column and amounts of packing material, etc). To the best of our knowledge, this is the first on-line flow injection molecularly imprinted solid phase extraction for the pre-concentration and determination of hydroxylate PAH metabolite in urine samples. The optimised method was successfully applied to the determination of 1-Hydroxypyrene in spiked urine samples, with recoveries in the range of 74–85% and RSD<4.6%. Under optimum experimental conditions, the linearity concentration range used was 10–400 μg L−1, R2>0.996. We obtained limit of detection and quantification of 3.1 μg L−1 and 10.5 μg L−1, respectively
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    Assessment of the impact of aquaculture facilities on transplanted mussels (Mytilus galloprovincialis): Integrating plasticizers and physiological analyses as a biomonitoring strategy
    (Elsevier, 2022-02-15) Rios Fuster, Beatriz; Alomar, Carme; Capó, Xavier; Silva, Mónica; Solé, Montserrat; Freitas, Rosa; Deudero, Salud; Paniagua González, Gema; Soliz Rojas, Dulce Lucy; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa Mª
    The growing plastic production and its continuous use is a significant problem. In addition, aquaculture practices have experienced a considerable growth and plastic is widely used in these activities, hence plasticizers must be considered due to their potential ecotoxicological impacts on species. Mussels placed inside an Integrated Multi-Trophic Aquaculture (IMTA) system and at two control locations were employed to quantify the ingestion of anthropogenic particles and associated chemical plasticizers, such as bisphenol A (BPA) jointly to bisphenol F (BPF) and bisphenol S (BPS), and phthalates represented by diethyl phthalate (DEP), dibutyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP). In addition, some metabolism and oxidative stress related parameters were measured in mussels’ whole soft tissue. Anthropogenic particle ingestion of mussels increased over time at the three locations and the following order of abundance of pollutants was observed: BPA> BPF> DEHP> DBP> BPS> DEP. Even though no differences according to location were found for pollutants’ occurrence, time trends were evidenced for BPA and DEHP. On the other hand, a location effect was observed for biomarkers with highest values detected in mussels located at the vicinities of the aquaculture facility. In addition, a reduced detoxification activity was observed over time parallel to BPA decrease.
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    An optical sensor for the determination of digoxin in serum samples based on a molecularly imprinted polymer membrane.
    (Elsevier, 2009-04) Durand Alegría, Jesús Senén; Paniagua González, Gema::virtual::2768::600; Fernández Hernando, Pilar::virtual::2769::600; Paniagua González, Gema; Fernández Hernando, Pilar; Paniagua González, Gema; Fernández Hernando, Pilar; Paniagua González, Gema; Fernández Hernando, Pilar
    This paper reports the synthesis and testing of a molecularly imprinted polymer membrane for digoxin analysis. Digoxin-specific bulk polymer was obtained by the UV initiated co-polymerisation of methacrylic acid and ethylene glycol dimethacrylate in acetonitrile as porogen. After extracting the template analyte, the ground polymer particles were mixed with plasticizer polyvinyl chloride to form a MIP membrane. A reference polymer membrane was prepared from the same mixture of monomers but with no template. The resultant membrane morphologies were examined by scanning electron microscopy. The imprinted membrane was tested as the recognition element in a digoxin-sensitive fluorescence sensor; sensor response was measured using standard solutions of digoxin at concentrations of up to 4 × 10−3 mg L−1. The detection limit was 3.17 × 10−5 mg L−1. Within- and between-day relative standard deviations RSD (n = 5) were in the range 4.5–5.5% and 5.5–6.5% respectively for 0 and 1 × 10−3 mg L−1 digoxin concentrations. A selectivity study showed that compounds of similar structure to digoxin did not significantly interfere with detection for interferent concentrations at 10, 30 and 100 times higher than the digoxin concentration. This simply manufactured MIP membrane showed good recognition characteristics, a high affinity for digoxin, and provided satisfactory results in analyses of this analyte in human serum.
  • Miniatura
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    A MIP-based flow-through fluoroimmunosensor as an alternative to immunosensors for the determination of digoxin serum samples
    (Springer, 2009-01-09) Durand Alegría, Jesús Senén; Paniagua González, Gema; Fernández Hernando, Pilar
    This work reports a comparative study of two automated flow-through fluorosensors for the determination of digoxin in serum samples: an immunosensor with an anti-digoxin polyclonal antibody as the reactive phase permanently immobilized on CPG, and a sensor with a selective reaction system based on a methacrylic molecularly imprinted polymer (MIP) synthesized by bulk polymerisation. The variables affecting the sensitivity and dynamic range of the sensors (e.g., the carrier and elution solutions, flow-rates, pH and reagent concentrations) were optimised and the binding characteristics of their reactive phases compared in a competitive fluorescent assay. Digoxin was reproducibly determined by both sensors at the mg L-1 level (detection limit= 1.20×10-3 mg L-1 and RSD= 4-7% for the immunosensor; detection limit= 1.7×10-5 mg L-1 and RSD= 1-2% for the MIP sensor). No cross reactivity with digoxinrelated compounds was seen for either sensor at a digoxin:interferent ratio of 1:100. The lifetime of the immunosensor was about 50 immunoassays; its shelf life, when unused, is about three months. The lifetime of the MIP sensor was over 18 months. Both sensors were used to determine the digoxin concentration of human serum samples with satisfactory results.
  • Miniatura
    Publicación
    Molecularly imprinted SPE and MEKC with in-capillary sample preconcentration for the determination of digoxin in human urine.
    (Wiley, 2012-06) Guijarro Díez, Miguel; Crego, Antonio Luis; Marina Alegre, María Luisa; Paniagua González, Gema::virtual::2777::600; Fernández Hernando, Pilar::virtual::2778::600; Paniagua González, Gema; Fernández Hernando, Pilar; Paniagua González, Gema; Fernández Hernando, Pilar; Paniagua González, Gema; Fernández Hernando, Pilar
    Molecularly imprinted solid-phase extraction (MISPE) combined with MEKC was used for clean-up, preconcentration and determination of digoxin in the presence of its aglycon digoxin (digoxigenin) in human urine samples. In addition, the use of an in-capillary sample concentration electrophoretic technique by sweeping was investigated to enhance the concentration sensitivity in MEKC. The highly selective, fast and effective sample pretreatment by MISPE along with the preconcentration by sweeping could overcome the low sensitivity of the highly efficient capillary electrophoresis separation with UV detection. The optimization of the variables affecting the separation as well as MISPE conditions procedure was carried out to select the best conditions of selectivity and sensitivity to determine digoxin at low concentration levels in urine. To demonstrate the suitability of the developed method several analytical characteristics (selectivity, linearity, accuracy, precision, and LOD) were evaluated. Satisfactory results were obtained in terms of linearity (r > 0.99), recovery (95.4–96.5% with RSD from 1.3% to 2.6%), precision (RSD from 0.3% to 1.7% for migration times and from 2.1% to 7.3% for corrected peak areas), and sensitivity (LODs of 6 μg/L with 5 mL of sample or 1.2 μg/L with 25 mL). The proposed MISPE-MEKC method was satisfactorily applied to the analysis of spiked human urine samples achieving a concentration factor up to 7500-fold.
  • Miniatura
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    Development of a molecularly imprinted polymeric membrane for determination of macrolide antibiotics from cow milk
    (Elsevier, 2022-05-17) Cañadas Soler, Raquel; Paniagua González, Gema; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa Mª
    A molecular imprinted membrane (MIM) was prepared for the selective binding of macrolide antibiotics by UV-initiated non-covalent imprinting approach . The membrane was modified by a UV - photographting technique in the presence of molecule templates of erythromycin (ERY) and spiramycin (SPI) with methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinker. The nanofunctionalized MIM obtained was characterized by a morphological study using scanning electron microscopy (SEM), as well as by a study of its adsorption capacity by online solid phase extraction (SPE) procedure. Variables affecting the MIM-SPE method were optimized to maximize the extraction of macrolide antibiotics of interest and a high-performance liquid chromatography (HPLC) method was used for the analysis. Good linearity and precision were obtained for ERY and SPI, with average recoveries up to 86.14 % and 34.73 %, respectively, with a relative standard deviation (RSD) lower than 6 %. In addition, selectivity was studied for other macrolides with similar structure to the templates, such as roxithromycin (ROX), josamycin (JOS), ivermectin (IVER) and tylosin (TYL). The proposed MIM-SPE-HPLC methodology was effectively applied to ERY and SPI determination in commercial doped semi-skimmed cow’s milk samples.
  • Miniatura
    Publicación
    A morphological study of molecularly imprinted polymers using the scanning electron microscope
    (Elsevier, 2006-01) Durand Alegría, Jesús Senén; Paniagua González, Gema; Fernández Hernando, Pilar
    Molecular imprinting is an emerging technique for producing polymers with applications in affinity-based separation, in biomimetic sensors, in catalysis, etc. This variety of uses relies upon the production of polymers with different affinities, specificities, sensitivities and loading capacities. Research into the development of molecular imprinted polymers (MIPs) with new or improved morphologies – which involves modification of the polymerisation process – is therefore underway. This paper reports a comparative study of non-covalent MIPs synthesised by “bulk” polymerisation using digoxin as template. These were synthesised under different conditions, i.e., changing the functional monomers employed (methacrylic acid or 2-vinylpyridine), the porogens (acetonitrile or dichloromethane) used, and by altering the volume of the latter. The polymerisation process was allowed to proceed either under UV light or in a thermostat-controlled waterbath. The surface morphology (was determined by scanning electron microscopy) and the ability of the different polymers to selectively rebind the template was then evaluated.
  • Miniatura
    Publicación
    Occurrence of common plastic additives and contaminants in mussel samples: Validation of analytical method based on matrix solid-phase dispersion
    (Elsevier, 2021-07) Cañadas Soler, Raquel; Garrido Gamarro, Esther; Paniagua González, Gema; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa Mª
    A new matrix solid-phase dispersion (MSPD) extraction methodology, combined with high-performance liquid chromatography equipped with a diode-array detector, was developed and validated for the simultaneous determination of 10 compounds in mussels from Galician Rias (Spain). These pollutants are compounds commonly used for plastic production as additives, as well as common plastic contaminants. The compounds selected were bisphenol-A, bisphenol-F, bisphenol-S, nonylphenol-9, nonylphenol, diethyl phthalate, dibutyl phthalate, di-2ethylhexyl phthalate, dichlorodiphenyltrichloroethane, dichlorodiphenyldichloroethane, and dichlorodiphenyldichloroethylene. The parameters affecting the MSPD extraction efficiency such as the type of sorbent, mass sample-sorbent ratio, and extraction solvent were optimised . The proposed method provided satisfactory quantitative recoveries (80‒100%), with relative standard deviations lower than 7%. In all cases, the matrix-matched calibration curves were linear in the concentration range of 0.32-120.00 µg/kg, with quantification limits of 0.25‒16.20 µg/kg. The novel developed MSPD-high-performance liquid chromatography methodology provided good sensitivity, accuracy, and repeatability for quality control analysis in mussels.
  • Miniatura
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    Fibreglass membrane chemically modified with amino-functionalised SBA-15 and its application in solid-phase extraction to determine macrolide antibiotics in eggs
    (Elsevier, 2024-10) González Gómez, Lorena; Morante Zarcero, Sonia; Pérez Quintanilla, Damián; Paniagua González, Gema; Garcinuño, Rosa M.; Fernández Hernando, Pilar; Sierra, Isabel
    Macrolides are a group of high-spectrum antibiotics used to treat animal ailments, sometimes these drugs can appear as residues in animal foods such as eggs, which must be controlled as required by the European Union. Therefore, in this paper a methodology based on solid–liquid extraction followed on the application of a new membrane-solid-phase extraction (membrane-SPE) was developed and validated for the extraction and purification of five macrolide antibiotics such as spiramycin (SPI), erythromycin (ERY), roxithromycin (ROX), josamycin (JOS) and tylosin (TYL), in egg samples for their analysis by high-performance liquid chromatography coupled to mass spectrometry analysis (HPLC-MS/MS). The newly synthesised membrane-based sorbent consisted of a fibreglass membrane chemically modified with silica SBA-15 type functionalised with amino groups (FGM-SBA-15-NH2). The optimal conditions for membrane-SPE on eggs were determined using a three-factor, three-level Box Behnken design (BBD). The conditions obtained were by loading with 4 mL of water and eluting with 3 × 2.5 mL of MeOH with ammonia solution (0.5 %, v/v). The methodology was validated according to Regulation (EU) 2021/808 showing good selectivity, linearity (R2 ≥ 0.993), low limits (MQL 1.1–2.1 ng/g, MDL 0.3–0.6 ng/g), acceptable decision limit for confirmation (CCα), good accuracy (recoveries 85–100 %) and an adequate precision (RSD ≤ 16 %). The FGM-SBA-15-NH2 proved to be reproducible in different batches and reusable around 70 times. Finally, the validated method was successfully applied to fourteen egg samples detecting SPI in one hen egg sample and JOS and ROX in one quail egg sample. The proposed methodology introduces a groundbreaking membrane-SPE approach, addressing limitations in conventional SPE methods. The use of functionalised silica to chemically modify FGM significantly improves its textural properties, allowing the simultaneous extraction and purification of macrolide antibiotics from egg samples.
  • Miniatura
    Publicación
    Selective extraction of diazepam and its metabolites from urine samples by a molecularly imprinted solid phase extraction (MISPE) method
    (MDPI, 2024-02) Gil Tejedor, Ana María; Bravo Yagüe, Juan Carlos; Paniagua González, Gema; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa Mª
    In this research, a molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using oxazepam (OZ) as a template molecule and was subsequently applied as a selective sorbent for the extraction of diazepam (DZP) and its metabolites in urine samples using an SPE cartridge. OZ, temazepam (TZ), nordiazepam (NZ) and DZP were analyzed in the final extracts by high-performance liquid chromatography with diode array detection (HPLC-DAD). The SPE extraction steps were optimized, and the evaluation of an imprinting factor was carried out. The selectivity of the method for OZ versus structurally related benzodiazepines (BZDs), such as bromazepam (BRZ), tetrazepam (TTZ) and halazepam (HZ), was investigated. Under the optimum conditions, the proposed methodology provided good linearity in the range of 10–1500 ng/mL, with limit of detection values between 13.5 and 21.1 ng/mL and recovery levels for DZP and its metabolites from 89.0 to 93.9% (RSD ≤ 8%) at a concentration level of 1000 ng/mL. The proposed method exhibited good selectivity, precision and accuracy and was applied to the analysis of urine samples from a real case of DZP intake.