Persona: Bravo Yagüe, Juan Carlos
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Bravo Yagüe
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Publicación Analysis of total arsenic content in purchased rice from Ecuador(Czech Academy of Agricultural Sciences, 2019-12-31) Atiaga Franco, Oliva L.; Otero, Xose L.; Gallego Picó, Alejandrina; Escobar Castañeda, Luis A.; Carrera Villacrés, David; Bravo Yagüe, Juan CarlosNatural and anthropogenic sources contribute to arsenic contamination in water and human food chain in Andean countries. Human exposure to arsenic via rice consumption is of great concern in countries where this crop is the dominant staple food, and limited information is available on the arsenic contamination on rice in Ecuador. This work was to contribute to the lack of knowledge analysing total arsenic by hydride generation-atomic absorption spectrometry in the samples of white, brown and parboiled rice purchased in Ecuadorian markets and produced in the two main rice wetlands in Ecuador, Guayas and Los Ríos, were carried out. For the samples from Guayas, arsenic concentration in white, brown and parboiled rice were 0.174 ± 0.014, 0.232 ± 0.021, and 0.186 ± 0.017 mg/kg respectively, whereas samples of white rice from Los Ríos showed a total arsenic level of 0.258 ± 0.037 mg/kg. This last arsenic concentration exceeds recommended maximum permissible limit by the FAO/WHO. Obtained data have available to estimate the Ecuadorian dietary exposure revealing serious health risk for populationPublicación Assessing matrix solid phase dispersion extraction strategies for determining bisphenols and phthalates in gilthead sea bream samples(MDPI, 2024-01) Soliz Rojas, Dulce Lucy; Paniagua González, Gema; Bravo Yagüe, Juan Carlos; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa MªMicroplastics (MPs) and nanoplastics (NPs) are widely spread in the environment, generating significant concern due to their potential impact on environmental health. Marine species usually ingest plastic fragments, mistaking them for food. Many toxic compounds, such as plastic additives that are not chemically bound to the plastic matrix, can be released from MPs and NPs and reach humans via the food chain. This paper highlights the development and validation of a straightforward solid–liquid extraction clean-up procedure in combination with a matrix solid-phase dispersion method using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) detection, enabling facile, precise, and reliable identification and quantitation of a total of six bisphenols and phthalates in gilthead sea breams. Under the optimized conditions, the developed method showed good linearity (R2 > 0.993) for all target compounds. The recoveries obtained were between 70 and 92%. The relative standard deviations (RSDs) for reproducibility (inter-day) and repeatability (intra-day) were less than 9% and 10%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) for the target compounds ranged from 0.11 to 0.68 µg/kg and from 0.37 to 2.28 µg/kg, respectively. A new, efficient extraction methodology for the determination of BPA, BPS, BPF, DBP, DEP, and DHEP in gilthead seabream has been optimized and validated.Publicación 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 MªNew 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, respectivelyPublicación Effects of UVC irradiation on polystyrene for healthcare packaging: Study by FTIR and Raman spectroscopy with thermoluminescence(Elsevier, 2024-02-14) Correcher, V.; García Guinea, Javier; Boronat Castaño, Cecilia; Bravo Yagüe, Juan CarlosThe interaction between ultraviolet C radiation (UVC) and polystyrene (PS) materials has been investigated, particularly in post-packaging irradiation processes for healthcare applications. Effective UVC penetration through PS materials, regardless of their thickness (0.16 and 0.40 mm) has been observed. However, the penetration effectiveness could be affected by the thickness of the PS material. Achieving optimal post-packaging UVC treatment requires a thorough evaluation of chemical composition and material thickness, especially in pharmaceutical and medical packaging industries. Preliminary results reveal minimal degradation in UVC-irradiated PS packaging samples, as supported by FTIR and Raman spectroscopy characterization. Minor variations could be attributed to intrinsic PS materials properties and/or their respective background, rather than the influence of UVC radiation. Consequently, PS materials exhibit resilience under the experimental conditions following UVC irradiation treatment. Furthermore, a comprehensive analysis of thermoluminescence (TL) emissions evaluates several commercial dosimeter materials for UVC radiation detection. The TLD-100 and TLD-200 dosimeters show potential as UVC detectors, displaying distinct responses linked to the non-ionizing component of UVC radiation at 310 ◦C and in the range of 150–250 ◦ C, respectively. However, the TLD-400 and GR-200 dosimeters are not suitable for UVC detection due to their spread TL emissions considering intensity and curve shape. This UVC-TL analysis consistently detects radiation in the proposed commercial dosimeter materials one-hour post-exposure, providing assurance that healthcare materials have been irradiated. Such analysis enhances reliability during extended UVC exposures, offering valuable insights for industries employing UVC-irradiated materials, particularly in healthcare applications.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 MªThis 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 L1 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 L1 and 0.8 and 0.98 g L1 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).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 MªIn 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.Publicación Detecting ultraviolet C radiation under polyethylene terephthalate (PET) packaging by thermoluminescence analysis using commercial dosimeters(Elsevier, 2024-03-07) Correcher, V.; Boronat Castaño, Cecilia; Bravo Yagüe, Juan CarlosFood irradiation is a proven technology that enhances food quality and safety by removing microorganisms and extending shelf life. Ultraviolet C radiation (UVC) has recently attracted interest due to its potential to inactivate foodborne pathogens. It relies on several advantages; however, there is limited research on its efficacy and safety particularly concerning food packaging materials such as polyethylene terephthalate (PET). This study reports on the effect of UVC radiation on commercial thermoluminescence dosimeters (namely, TLD-100, TLD-200, TLD-400 and GR-200) placed under PET films with different thicknesses (0.10, 0.42, and 0.60 mm). The results indicate the potential use of these materials for the detection of UVC radiation passing through the randomly selected PET samples. Fourier transform infrared spectroscopy assesses potential structural and chemical alterations in the PET induced by UVC exposure.Publicación Comparing the effect of electron beam, beta and ultraviolet C exposure on the luminescence emission of commercial dosimeters(Elsevier, 2023-07-05) Correcher, Virgilio; Sarasola Martín, Iciar; García Guinea, Javier; Benavente Cuevas, José Francisco; Boronat Castaño, Cecilia; Bravo Yagüe, Juan CarlosThis paper reports on the luminescence characterization of TLD-100 (LiF: Ti, Mg), TLD-200 (CaF2: Dy), TLD-400 (CaF2: Mn) and GR-200 (LiF: Mg, Cu, P) dosimeters exposed to electro beam, beta and ultraviolet C radiation -UVC-. All of them show high sensitivity to radiation regardless of whether it is ionizing or partially ionizing radiation based on their luminescence properties (cathodoluminescence -CL- or thermoluminescence -TL-). CL emission differs significantly among them in shape and intensity due to their chemical compositions. LiF samples display three maxima at: (i) 300-450 nm linked to intrinsic and structural defects, (ii) a green waveband probably due to F3+ centres or the presence of hydroxyl groups and (iii) the red-infrared emission band associated with F2 centres. However, CL spectra from the CaF2 dosimeters display meaningful differences due to the dopant. TLD-200 is characterized by an emission with four sharp individual peaks in the green-IR spectral region (due to the Dy3+), whilst TLD-400 exhibits a broad maximum peaked at ̴ 500 nm (linked to the Mn2+). On the other hand, the variation in the TL glow curves allows to discriminate the TLDs exposed to beta and UVC radiation since they give rise to different chemicalphysical processes and that have been studied from the estimation of the kinetic parameters by means of the Computerised Glow Curve Deconvolution (CGCD) method.Publicación Identification and morphological characterization of different types of plastic microparticles(Elsevier, 2024-05-15) Soliz Rojas, Dulce Lucy; Paniagua González, Gema; Muñoz Arnanz, Juan; Bravo Yagüe, Juan Carlos; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa MªThe knowledge of the polymeric composition of microplastics (MPs) is interesting because offers useful information on the resistance, durability, and degradability of these materials, also allowing progress in the control of this contamination. However, there is currently a lack of reliable standardized methods for the identification, and characterization of the plastic microparticles. This work uses different techniques in a complementary manner for the identification, and characterization of MPs that more frequently are found in the environment. A total of 10 types of plastics were collected (polystyrene (PS), polyethylene terephthalate (PETE), polyethylene (PE), high- and low-density polyethylene (HDPE and LDPE, respectively), polyvinyl chloride (PVC), polypropylene (PP), polytetrafluoroethylene (PTFE), Polyamide (PA, Nylon 6,6) and poly-carbonate (PC)) and their chemical identification were analyzed by reflectance-attenuated infrared (FTIR-ATR). Furthermore, the samples were observed using light microscopy, and scan-ning electron microscopy (SEM). Also, staining with 12 different dyes was performed to improve the identification of microplastics. The results of this study revealed that PETE, PE, HDPE and LDPE, whose SEM images exhibited smoothness and flat uniformity of their surface, were not (or less) susceptible to adsorb staining solutions while PP, PA, PVC, and PTFE, were capable of adsorbing the dye solutions.Publicación Methacrylic acid-ethylene glycol dimethacrylate polymeric sorbent for the removal of estrogens from water(['Estrogens', 'Removal', 'Polymer', 'Sorbent', 'Waters', 'Balaban Publishers – Desalination Publications'], 2018-11) Gallego, Alejandrina; Bravo Yagüe, Juan Carlos; Paniagua González, Gema; Fernández Hernando, Pilar; Garcinuño Martínez, Rosa MªThe presence of estrogens in environmental waters can cause adverse effects to aquatic organisms. In the last years, diverse researches have been focussed on the development of cost-effective methods for the removal of these compounds in water. In this paper, a series of methacrylic acid-ethylene glycol dimethacrylate polymers with different monomers ratio were synthesised by photochemical (UV irradiation at 365 nm) or thermal (oven at 60°C) initiation. Batch and continuous flow experiments were carried out to evaluate the capacity of these polymers to adsorb estradiol (E2), ethinylestradiol (EE2) and dienestrol (DEN). Adsorption isotherm studies revealed that Langmuir isotherm model was fitted with a better correlation than Freundlich isotherm. Finally, continuous flow experiments were carried out by microcolumn studies to check the suitability of the polymeric sorbent for the removal of estrogens from real water samples. When continuous removal experiments at 8 mL min–1 flow rate were carried out, breakthrough adsorption capacities of 28.5, 38 and 69.7 mg g–1 for E2, EE2 and DEN, respectively, were achieved.