8 results on '"Francisco Javier Guzmán Bernardo"'
Search Results
2. Analytical metrology for nanomaterials: Present achievements and future challenges
- Author
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Francisco Javier Guzmán Bernardo, R.C. Rodríguez Martín-Doimeadios, Sara López-Sanz, and Ángel Ríos
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Analytical control ,Chemistry ,End user ,010401 analytical chemistry ,02 engineering and technology ,Analytical science ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Analytical Chemistry ,Nanomaterials ,Characterization (materials science) ,Metrology ,Variety (cybernetics) ,Critical discussion ,Systems engineering ,Environmental Chemistry ,0210 nano-technology ,Spectroscopy - Abstract
Nanoscience and nanotechnology have emerged in recent years as revolutionary trends in almost all fields of activity. Their impact has taken place in the analytical science, too. Firstly, because the use of nanomaterials as analytical tools is more and more frequent and secondly, because the analytical control of nanomaterials in a wide variety of samples is required. In both aspects, analytical metrology for nanomaterials is involved as the scientific discipline responsible for providing reliable information (based on experimental measurements) to end users. This review presents a general view of the present achievements and the future challenges of analytical metrology for nanomaterials. Selected references and a critical discussion are reported for illustrating this important role of the metrology applied to nano-world.
- Published
- 2019
3. Magnetic cellulose nanoparticles coated with ionic liquid as a new material for the simple and fast monitoring of emerging pollutants in waters by magnetic solid phase extraction
- Author
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Shehdeh Jodeh, Francisco Javier Guzmán Bernardo, Feras Abujaber, R.C. Rodríguez Martín-Doimeadios, Ángel Ríos, and Mohammed Zougagh
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Detection limit ,Chromatography ,Chemistry ,010401 analytical chemistry ,Extraction (chemistry) ,010501 environmental sciences ,01 natural sciences ,High-performance liquid chromatography ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Adsorption ,Desorption ,Ionic liquid ,Sample preparation ,Solid phase extraction ,Spectroscopy ,0105 earth and related environmental sciences - Abstract
Magnetic cellulose nanoparticles (MCNPs) coated with 1-butyl-3-methylimidazolium hexafluoro phosphate [C4MIM][PF6] ionic liquid (IL) through electrostatic interactions are proposed for the first time as sorbents in a magnetic solid phase extraction (MSPE) method for the determination of paracetamol (PAR), ibuprofen (IBU), naproxen (NAP) and diclofenac (DIC) in natural waters. The parameters that affect adsorption (dispersive solvent, amount of IL, pH and salt content) and desorption (desorption solvent, type of energy and time) were studied. The values that provided the maximum adsorption efficiency and extraction recovery were selected as optimum conditions for adsorption and desorption, respectively. Under the optimum conditions, the adsorption and desorption of all analytes was simultaneous and quantitative. High performance liquid chromatography (HPLC) with ultra violet (UV) and fluorescence (FL) detector was used after the sample preparation. The precision, expressed as relative standard deviation was between 1.4 and 7.6%. Limits of detection and quantification were in the range 3.2–7.2 μg L− 1 and 11–24 μg L− 1, respectively. Moreover, the proposed method provides enrichment factors from 29.0 to 34.2. Recovery studies on 10 mL of spiked tap, river and dam water samples at 50 and 100 μg L− 1 were carried out. The extraction recoveries were from 85 to 116%, and were in a comparable range regardless of the type of water. The method is simple, rapid, and environmentally friendly.
- Published
- 2018
4. Determination of dabrafenib and trametinib in serum by dispersive solid phase extraction with multi-walled carbon nanotubes and capillary electrophoresis coupled to ultraviolet/visible detection
- Author
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Gregorio Castañeda Peñalvo, Francisco Javier Guzmán Bernardo, Juana Rodríguez Flores, and Isabel Lizcano Sanz
- Subjects
Detection limit ,Chromatography ,Chemistry ,010401 analytical chemistry ,Extraction (chemistry) ,Dabrafenib ,02 engineering and technology ,Electrolyte ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Electrophoresis ,chemistry.chemical_compound ,Capillary electrophoresis ,medicine ,Solid phase extraction ,0210 nano-technology ,Acetonitrile ,Spectroscopy ,medicine.drug - Abstract
Dispersive solid phase extraction (DSPE) prior to capillary electrophoresis with ultraviolet and visible detection was used for the first time for the determination of dabrafenib (DB) and trametinib (TT), the main drugs used for the treatment of metastatic melanoma, in serum. Six different magnetic and non-magnetic nanomaterials were evaluated as DSPE sorbents for the extraction and preconcentration of the analytes. The best results were obtained with 4 mg of pristine multi-walled carbon nanotubes in phosphate buffer (pH 12.5; 10 mM). The electrophoretic separation was carried out in a fused silica capillary (30 cm × 75 µm i.d.) at 22 °C in a voltage ramp (8–12 kV) with a background electrolyte consisting of borate buffer (pH 9.2; 25 mM), 37 mM sodium dodecylsulfate, 22% (v/v) acetonitrile and 3% (v/v) methanol. The preconcentration factor achieved was 4, and the limits of detection were 0.012 and 0.008 mg L−1 for DB and TT in serum, respectively. Linearity was observed up to 5 mg/L and precision (n = 7) was below 3% in migration time and 7.8% in peak areas. The present method was applied to six patients under treatment with DB and TT for metastatic melanoma. It requires a less sophisticated instrumentation and lower volume of harmful organic solvents than the methods reported up to present.
- Published
- 2021
5. Screening-confirmation strategy for nanomaterials involving spectroscopic analytical techniques and its application to the control of silver nanoparticles in pastry samples
- Author
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Francisco Javier Guzmán Bernardo, Nuria Rodríguez Fariñas, Ana I. Corps Ricardo, R.C. Rodríguez Martín-Doimeadios, and Ángel Ríos
- Subjects
Silver ,Metal Nanoparticles ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Mass Spectrometry ,Silver nanoparticle ,Analytical Chemistry ,Nanomaterials ,law.invention ,Luminol ,chemistry.chemical_compound ,law ,Particle Size ,Instrumentation ,Inductively coupled plasma mass spectrometry ,Spectroscopy ,Reliability (statistics) ,Chemiluminescence ,Detection limit ,Chemistry ,Reproducibility of Results ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Asymmetric flow field flow fractionation ,0210 nano-technology - Abstract
The full characterization of nanomaterials (NMs), which requires a range of different and expensive equipment, is not always necessary to meet certain demands of information. Qualitative analytical methods are ideal alternatives when only a piece of information is required. In this work, a qualitative method for the screening of NMs has been developed and statistically validated for the first time, with silver nanoparticles (AgNPs) as a proof of concept. It is based on the generation of chemiluminescence of the luminol/Ag+ system in alkaline media in the presence of AgNPs. Measurements are obtained in a short time with a simple instrument. Probability of detection (POD) curves were constructed at three cut-off values next to the limit of detection of the chemiluminescent method. The unreliability region (UR) was from 0.50 to 1.82 μg L−1. Currently, no regulation on AgNPs exists, but the present method was successfully tested for a hypothetical threshold of 2.5 μg L−1 of 40 nm AgNPs. The method was applied to silver colored pearls, with silver (E-174) or aluminum (E-173) coating, used for decoration of pastry. Performance parameters such as false negative and positive rates as well as specificity, sensitivity and reliability rates were calculated for validation. The results of the screening method were confirmed by asymmetric flow field flow fractionation coupled to inductively coupled plasma mass spectrometry (AF4-ICP-MS). The proposed screening method is simple, fast, economic, and easy to transfer to routine laboratories in the field of food safety.
- Published
- 2021
6. Ionic liquid dispersive liquid-liquid microextraction combined with LC-UV-Vis for the fast and simultaneous determination of cortisone and cortisol in human saliva samples
- Author
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Feras Abujaber, Ana I. Corps Ricardo, Ángel Ríos, Francisco Javier Guzmán Bernardo, and R.C. Rodríguez Martín-Doimeadios
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Saliva ,Analyte ,Time Factors ,Hydrocortisone ,Liquid Phase Microextraction ,Clinical Biochemistry ,Pharmaceutical Science ,Ionic Liquids ,01 natural sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Drug Discovery ,medicine ,Humans ,Spectroscopy ,Detection limit ,Chromatography ,010405 organic chemistry ,Chemistry ,010401 analytical chemistry ,Extraction (chemistry) ,Osmolar Concentration ,Hydrogen-Ion Concentration ,0104 chemical sciences ,Solvent ,Cortisone ,Ionic strength ,Ionic liquid ,Solvents ,medicine.drug ,Chromatography, Liquid - Abstract
Ionic liquid dispersive liquid–liquid microextraction (IL-DLLME) was used for the first time for the extraction and preconcentration of cortisone and cortisol from human saliva samples. This approach allows the determination of both compounds by liquid chromatography (LC) with ultra-violet/visible (UV/Vis) detection at physiological levels. The IL 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6] and methanol (MeOH) were used as extraction and dispersive solvents, respectively. The parameters that affect extraction (ionic strength, pH, amount of IL, volume of dispersive solvent, vortex and centrifugation time) were optimized. Limits of detection were 0.11 (cortisone) and 0.16 μg L−1 (cortisol) and enrichment factors of 5.0 (cortisol) and 6.3 (cortisone) were achieved. Recoveries from 83.3 ± 1.6 to 115.8 ± 3.0% were obtained for the extraction of the target analytes in spiked human saliva samples. Intraday and interday precision, expressed as relative standard deviation, was below 4.2 and 7.8% for cortisone and cortisol, respectively. The method was successfully applied to the determination of cortisone and cortisol in saliva from healthy volunteers (n = 9) in the morning and in the evening. The method is simple, faster, and more environmentally friendly than the current ones.
- Published
- 2018
7. Development and validation of an analytical methodology for the determination of p,p′-DDT, p,p′-DDE and p,p′-DDD in fish oil pills
- Author
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R.C. Rodríguez Martín-Doimeadios, Nuria Rodríguez Fariñas, Juan José Berzas Nevado, and Francisco Javier Guzmán Bernardo
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Vitamin ,Detection limit ,chemistry.chemical_compound ,Electron capture detector ,Analyte ,Chromatography ,chemistry ,Analytical technique ,Cod liver oil ,Gas chromatography ,Fish oil ,Spectroscopy ,Analytical Chemistry - Abstract
An analytical methodology was proposed and validated to be applied to the determination of p , p′ -DDT and its metabolites p , p′ -DDE and p , p′ -DDD in fish oil. The analytical procedure presented in this paper involves a single-step clean up process prior to the analysis. A solution of 1,2,3,4-tetrachloronaphtalene was used as internal standard. The analytical technique used was gas chromatography coupled to an electron capture detector. Details on the validation process are provided. The limits of detection ranged from 2.6 to 4.7 pg μL − 1 . The BCR 598 standard reference material (cod liver oil) was used to evaluate the performance of the methodology with satisfactory recoveries for all the compounds. The analytes were determined in three different fish oil pills sold in Spain as a supplementary vitamin support. The sum of p , p′ -DDT and metabolites was from 13.2 to 51.3 ng g − 1 , the dominant compound being p , p′ -DDE.
- Published
- 2007
8. Development and validation of a capillary zone electrophoresis method for the determination of propranolol and N-desisopropylpropranolol in human urine
- Author
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Juan José Berzas Nevado, Gregorio Castañeda Peñalvo, Juana Rodriguez Flores, and Francisco Javier Guzmán Bernardo
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Detection limit ,Analyte ,Chromatography ,Chemistry ,Elution ,Analytical chemistry ,Fractional factorial design ,Biochemistry ,Analytical Chemistry ,Matrix (chemical analysis) ,Electrophoresis ,Capillary electrophoresis ,Environmental Chemistry ,Solid phase extraction ,Spectroscopy - Abstract
A simple, rapid and sensitive procedure using solid phase extraction and capillary zone electrophoresis for the determination of propranolol (a beta-blocker) and one of its metabolites, N -desisopropylpropranolol, has been developed and validated. The optimum separation of both analytes was obtained in a 37 cm × 75 μm fused silica capillary using 20 mmol/L phosphate buffer (pH 2.2) as electrolyte, at 25 kV and 30 °C, and hydrodynamic injection for 5 s. Prior to the electrophoretic separation, the samples were cleaned up and concentrated using a C 18 cartridge and then, eluted with methanol, allowing a concentration factor of 30. Good results were obtained in terms of precision, accuracy and linearity. The limits of detection were 28 and 30 μg/L for N -desisopropylpropranolol and propranolol, respectively. Additionally, a robustness test of the method was carried out using the Plackett–Burman fractional factorial model with a matrix of 15 experiments. The presented method has been applied to the determination of both compounds in human urine.
- Published
- 2006
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