Persona:
Paniagua González, Gema

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Autor: Fernández Hernando, Pilar × search.filters.applied.f.itemDepartamento: Ciencias Analíticas ×

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Mostrando 1 - 10 de 26
  • Miniatura
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    Occurrence of common plastic additives and contaminants in raw, steamed and canned mussel samples from different harvesting areas using MSPDHPLC methodology
    (Elsevier, 2024-04) Garrido Gamarro, Esther; Soliz Rojas, Dulce Lucy; Paniagua González, Gema; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa Mª
    Microplastics are a complex mix of chemicals containing polymers and certain plastic additives such as bisphenols and phthalates. These particles are porous materials that can also sorb contaminants from their surroundings, and leach chemicals from the particle under certain circumstances. Aquatic animals can ingest microplastic particles, which mostly bioaccumulate in the gastrointestinal tract of animals. In terms of dietary exposure, small animals consumed whole such as mussels, contribute more to the dietary intake of microplastic particles. Plastic additives and contaminants are not chemically bound to the polymers, and certain processing methods or cooking processes result in the release of these chemicals that leach from the plastic particles, leaving them more available for absorption when ingested. Analytical methods are crucial for a better understanding of the occurrence of plastic additives and contaminants in aquatic products, and to know certain circumstances and treatments that influence human exposure. This study uses an MSPD-HPLC methodology for the simultaneous determination of 9 analytes (BPA, BPF, BPS, DEP, DBP, DEHP, DDD, DDT, and DDE) analyzing, for the first time, the occurrence of these chemicals in raw, steamed and canned mussels of two different harvesting areas (Atlantic and the Mediterranean), becoming one of the most efficient methodologies for determining the presence of these analytes in very complex food matrices, able to define the changes in cooking and processing activities. The results showed that the heat and pressure treatment could influence the migration of plastic additives from microplastic particles present in mussels to the cooking liquids.
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    Development of a molecularly imprinted polymeric membrane for determination of macrolide antibiotics from cow milk
    (Elsevier, 2022-05-17) Cañadas, Raquel; Paniagua González, Gema; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa Mª; https://orcid.org/0000-0002-2935-6655
    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.
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    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.
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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 Fiol, Xavier; Silva, Mónica; Solé, Montserrat; Freitas, Rosa; Deudero, Salud; Paniagua González, Gema; Soliz Rojas, Dulce Lucy; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa Mª; https://orcid.org/0000-0002-3499-5494
    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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    Permanent oriented antibody immobilization for digoxin determination with a flow-through fluoroimmunosensor
    (Springer, 2003-02-28) Durand Alegría, Jesús Senén; Pérez Conde, Concepción; Fernández Hernando, Pilar; Paniagua González, Gema
    Digoxin is a very important compound in clinical chemistry and is indicated in the treatment of congestive heart failure and artery disease. The measurement of serum digoxin concentration is necessary owing to the narrow therapeutic range of this drug. Further, even with similar dosage regimens, the biological response of patients often results in very different concentrations of digoxin in serum. Concentrations of greater than 2.6 mmol/L are generally interpreted as toxic in adult patients. Most methods for digoxin determination are based on gas chromatography or radiochemical and enzymatic immunoassay techniques. However, some of these methods are tedious and difficult to automate. Nowadays, they are being replaced by more practical immunoassay techniques, involving, for example, fluorescent immunosensors that allow rapid, automated and selective digoxin determinations. This paper reports a new flow–through fluoroimmunosensor for digoxin determination, the function of which is based on antibodies immobilized on an inmunoreactor of controlled pore glass (CPG). The immunosensor has a detection limit of 1.20 μg/L and provides high reproducibility (RSD = 4.5% for a concentration of 0.0025 mg/L, and RSD = 6.7% for 0.01 mg/L). The optimum working concentration range was found to be 1.2×10-3 - 4.0×10-2 mg/L. The lifetime of the immunosensor was about 50 immunoassays, if stored unused its lifetime can be extended to three months. A sample speed of about 10–12 samples per hour can be attained. Possible interference from substances with structures similar to digoxin (morphine, heroine, tebaine, codeine, pentazocine and narcotine) was investigated. No cross-reactivity was seen at the highest digoxin:interferent ratio studied (1:100). The proposed fluoroimmunosensor was successfully used to determine digoxin concentrations in human serum samples.
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    Assessment of molecularly imprinted polymers as selective solid-phase extraction sorbents for the detection of cloxacillin in drinking and river water
    (MDPI, 2023-11-03) Collado, Eduardo José; Paniagua González, Gema; Bravo Yagüe, Juan Carlos; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa Mª
    This paper describes a new methodology for carrying out quantitative extraction of cloxacillin from drinking and river water samples using a molecularly imprinted polymer (MIP) as a selective sorbent for solid-phase extraction (MISPE). Several polymers were synthesized via thermal polymerization using cloxacillin as a template, methacrylic acid (MAA) as a functional monomer, ethyleneglycoldimethacrylate (EGDMA) as a cross-linker and different solvents as porogens. Binding characteristics of the adequate molecularly imprinted and non-imprinted (NIP) polymers were evaluated via batch adsorption assays following the Langmuir and Freundlich isotherms and Scatchard assays. The parameters related to the extraction approach were studied to select the most appropriate polymer for cloxacillin determination. Using the optimized MIP as the SPE sorbent, a simple sample treatment methodology was combined with high-performance liquid chromatography (HPLC) to analyze cloxacillin residues in drinking and river water. Under the optimum experimental conditions, the MISPE methodology was validated using spiked samples. The linearity for cloxacillin was assessed within the limits of 0.05–1.5 g L􀀀1 and the recovery percentage was higher than 98% (RSD < 4%). The limits of detection and limits of quantification were 0.29 and 0.37 g L􀀀1 and 0.8 and 0.98 g L􀀀1 for drinking and river water, respectively. The selectivity of MIP against other ß-lactam antibiotics with similar structures (oxacillin, cefazoline, amoxicillin and penicillin V) was studied, obtaining a good recovery higher than 85% for all except cefazoline. The proposed MISPE-HPLC methodology was successfully applied for the detection of cloxacillin in drinking water from Canal de Isabel II (Madrid) and river water from the Manzanares River (Madrid).
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    Determination of atropine and scopolamine in honey using a miniaturized polymer-based solid-phase extraction protocol prior to the analysis by HPLC-MS/MS
    (Elsevier, 2024-04-09) Fernández Pintor, Begoña; Gañán Aceituno, Judith; Morante Zarcero, Sonia; Sierra Alonso, Isabel; Paniagua González, Gema; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa Mª
    Two homopolymers have been prepared employing methacrylic acid and 4-vynylpiridine as functional monomers (p-MAA, p-4-VP) through an easy and quick precipitation polymerization method for application as sorbents in solid-phase extraction (SPE) to determine atropine and scopolamine in honey. The optimized SPE conditions were as follows: 25 mg of p-MAA, 4 mL of sample loading volume (diluted honey 1:10 with water), 4 mL of elution solvent (methanol/water with 1 % formic acid, 80/20, v/v). The extracts were analyzed by HPLC-MS/MS. The cartridges were reusable for forty cycles demonstrating an environmentally friendly approach. The methodology was validated in terms of linearity, accuracy, precision, selectivity, matrix effect and sensibility, highlighting the absence of matrix effect. The miniaturized polymer-based SPE was successfully applied to fifteen honeys, showing concentrations up to 7.23 ng/g in the most contaminated honey. All quantified honey samples (5 in total) were of multifloral type.
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    Statistical evaluation of fluoride contamination in groundwater resources of Santiago del Estero Province , Argentina
    (Elsevier, 2020-11) Rondano Gómez, Karina del Valle; López Pasquali, Clara Elena; Paniagua González, Gema; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa Mª
    This study investigates the suitability of statistical techniques for evaluating the fluoride content and the groundwater quality from Robles Department (RD) and Banda Department (BD) areas in Santiago del Estero (Argentina). Groundwater mineralization is driven by many processes such as, weathering of volcanic products, geothermal activity and human activities. The original matrix consisted of 9 parameters estimated (fluoride content, pH, conductivity, environmental and water temperatures, total dissolved solids, chloride concentration, hardness and alkalinity) from 110 groundwater samples collected of 23 selected scattered rural areas. Groundwater samples were obtained by sampling in wells at different depths. The fluoride levels were determined by a standard colorimetric method in two seasonal periods, dry (from April to September) and rainy (from October to March). Parameters such as pH and total dissolved solids (TDS) reached their highest values in the rainy season; while the temperature, alkalinity, chloride concentration and hardness did it in the dry season. In both seasons, the environmental temperature average was 22 °C. Regarding the fluoride content, approximately the fifty percent of the analyzed groundwater samples exceeded the upper limit (1.0 mg/L) established by the current legislation, obtaining concentration levels between 0.01-2.80 mg/L. This study demonstrates the usefulness of univariate (quartiles calculation, interquartile range IQR) and multivariate statistical method of principal component analysis (PCA) and clusters to establish a better understanding of the environmental status of the region studied and the degree of pollution.
  • Miniatura
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    Determination of digoxin in serum samples using a flow-through fluorosensor based on a molecularly imprinted polymer
    (Elsevier, 2008-06-15) Durand Alegría, Jesús Senén; Paniagua González, Gema; Fernández Hernando, Pilar
    This work describes the development of a competitive flow-through FIA assay for digoxin using a molecularly imprinted polymer (MIP) as the recognition phase. In previous work, a number of non-covalent imprinted polymers were synthesised by “bulk” polymerisation. The digoxin binding and elution characteristics of these MIPs were then evaluated to obtain a highly selective material for integration into a sensor. The optimum MIP was synthesised by photo-initiated polymerisation of a mixture containing digoxin, MAA, EDGMA and AIBN in acetonitrile. The bulk polymer was ground and sieved and the template removed by Soxhlet extraction in MeOH/ACN. The MIP was packed into a flow cell and placed in a spectrofluorimeter to integrate the reaction and detection systems. The physical and chemical variables involved in digoxin determination by the sensor (nature and concentration of solution, flow rates, etc.) were optimised. Binding with the non-imprinted polymer (NIP) was also analysed. The new fluorosensor showed high selectivity and sensitivity, a detection limit of 1.7 × 10−2 μg l−1, and high reproducibility (R.S.D. of 1.03% and 1.77% for concentrations of 1.0 × 10−3 and 4.0 × 10−3 mg l−1, respectively). Selectivity was tested by determining the cross-reactivity of several compounds with structures analogous to digoxin. Under the assay conditions used, in which the potential interfering compounds were in concentrations 100 times higher than that of the analyte, no interference was recorded. The proposed fluorosensor was successfully used to determine digoxin concentration of human serum samples.
  • 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.