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Paniagua González, Gema

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Paniagua González
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Mostrando 1 - 10 de 23
  • Miniatura
    Publicación
    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).
  • Miniatura
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    Evaluation of total phenol pollution in water of San Martin Canal from Santiago del Estero, Argentina.
    (Elsevier, 2018-05) Acosta Rosales, Carina Andrea; López, Clara; Paniagua González, Gema; Garcinuño Martínez, Rosa Mª; Fernández Hernando, Pilar
    Santiago del Estero is a province located in northwestern Argentina. The Dulce River is used for irrigation through a vast network of channels and ditches, including the San Martin Canal (SMC), which crosses the capital city of Santiago del Estero. This canal's water is used for drinking, as well as recreational use for the general population. However, this river has been seriously polluted for several decades. The present study focuses on the identification and the quantification of the water pollution levels of total phenols in the SMC according to the seasonal periods. Water samples from various areas of the canal in different months of the year, extending from December to September, were collected for analysis. Additionally, the concentration of total dissolved solids (TDS), chlorides, sulphates, nitrites and organic matter, as well as water hardness and alkalinity, were analysed in order to conduct a more complete study of the contamination of this area. The results showed a worrying total phenol concentration that exceeded the limit set by Argentine legislation for drinking water, as well as water for recreational use (5 μg/L). The total phenol (TP) concentration was directly determined by a molecular absorption spectroscopy method based on a new flow injection analysis system (FIA). Under the selected experimental conditions, the detection and quantification limits were 0.0490 and 0.1633 μg/mL, respectively. The developed method provides a number of improvements related to the speed of analysis, the restricted consumption of the reagents and sample volumes and the unnecessary sample treatment that contribute to environmentally friendly analytical chemistry. The results showed that TP make a significant contribution in the SMC pollution, especially during the months of April (400 ± 110 μg/L) and September (240 ± 20 μg/L). A high sulphate concentration that was higher than the limit allowed by the legislation was also found.
  • Miniatura
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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, C. E.; 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
    Publicación
    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; 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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    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.
  • 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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    Enhancement of a Simple, Economic and Eco-Friendly Analytical Approach for the Extraction and Determination of Endocrine Disruptors from Plastics in Shrimp
    (MDPI, 2024-07-12) Soliz Rojas, Dulce Lucy; García González, Jorge; Paniagua González, Gema; Garcinuño Martínez, Rosa Mª; Bravo Yagüe, Juan Carlos; Fernández Hernando, Pilar
    The economic significance of the shrimp industry relies heavily on the comprehensive utilization of all of the shrimp’s parts. However, this importance is often threatened by common challenges such as disease and pollution, caused by prominent contaminants that are capable of exerting adverse effects either directly as physical pollutants or indirectly through the incorporation of additives or adsorbed chemicals. Among these substances are endocrine disruptors, which pose risks to both wildlife and human populations. In this study, 11 endocrine-disrupting compounds were determined (3 bisphenols, 3 phthalates, 3 pesticides, and 2 nonylphenols) through the development of a cost-effective, greener and cost-friendly method based on solid-phase matrix dispersion (MSPD) with high-performance liquid chromatography coupled with diode array detection (HPLC-DAD). Determinations were performed on different parts of the shrimp: the cephalothorax, abdomen, intestine and shell. Several variables were optimized in the extraction, separation and detection phases, resulting in average recoveries of about 90%. The limit of detection (LOD) varies depending on the analyte and matrix. At concentrations of 1 mg/kg in the cephalothorax+shells and 1.25 mg/kg in the abdomen+intestine, all compounds were detected, except for nonylphenols. The developed method has allowed the simultaneous determination of 11 endocrine disruptors in different parts of the shrimp samples. Furthermore, the MSPD has been demonstrated to be an efficacious, selective, and streamlined sample extraction method, eliminating the necessity for pretreatment steps such as centrifugation and filtration, as well as the use of large volumes of solvents.
  • Miniatura
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    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.
  • Miniatura
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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.
  • Miniatura
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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, 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.