Angel Raigosa Rios - Academia.edu (original) (raw)
Papers by Angel Raigosa Rios
Journal of AOAC INTERNATIONAL
After a brief introduction to the generic aspects of automation in analytical laboratories, the d... more After a brief introduction to the generic aspects of automation in analytical laboratories, the different approaches to quality in analytical chemistry are presented and discussed to establish the following different facets emerging from the combination of quality and automation: automated analytical control of quality of products and systems; quality control of automated chemical analysis; and improvement of capital (accuracy and representativeness), basic (sensitivity, precision, and selectivity), and complementary (rapidity, cost, and personnel factors) analytical features. Several examples are presented to demonstrate the importance of this marriage of convenience in present and future analytical chemistry.
The Modern Language Journal
This study investigated the concept of corrective feedback in second language learning as a learn... more This study investigated the concept of corrective feedback in second language learning as a learning resource, recasting it as feedback-seeking behavior. Dweck's (1999) mindsets, Korn and Elliot's (2016) achievement goals, and Ashford's (1986) model of feedback-seeking behavior were re-operationalized in the context of language learning. Questionnaire data from 287 college students studying foreign languages in the United States confirmed that learners make calculated decisions regarding whether to seek feedback, by what method, and from what source, based on their own perceptions of the costs and values associated with different feedback-seeking strategies, which are, in turn, largely predicted by the learners? language mindsets and achievement goals. Learners with a growth language mindset and development-approach goals sought feedback using both monitoring and inquiry methods and from teachers and others. Learners with a fixed language mindset and demonstration goals sought feedback only by method of inquiry but from different sources depending on the valence (approach vs. avoidance) of their goals.
Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment, Jan 26, 2018
A simple and rapid microextraction procedure is reported on the use of ionic liquid in combinatio... more A simple and rapid microextraction procedure is reported on the use of ionic liquid in combination with magnetic nanocellulose hybrid nanoparticles. The procedure is ultrasound-assisted and applicable to selective preconcentration of neonicotinoid insecticides from milk samples, prior to being analysed by liquid chromatography-mass spectrometry. The extraction procedure uses small volume of organic solvents (<1 mL), and there is no need for centrifugation. In the experimental approach the ionic liquid was quickly disrupted by an ultrasonic probe and dispersed in milk samples in a cloudy form. At this stage, neonicotinoid insecticides were extracted into the fine droplets of ionic liquid. Then small amounts of magnetic nanocellulose hybrid nanoparticles were dispersed into the sample solutions to adsorb the ionic liquid containing the analytes and phase separation was completed. The ionic liquid allowed the microextraction of the analytes and a small volume of acetonitrile was use...
Bioanalysis, 2018
The preparation of magnetic multi-walled carbon nanotube poly(styrene-co-divinylbenzene) for prop... more The preparation of magnetic multi-walled carbon nanotube poly(styrene-co-divinylbenzene) for propranolol magnetic solid-phase extraction is described. A study comparing propranolol adsorption and desorption was performed with only magnetic multi-walled carbon nanotubes, and different poly(styrene-co-divinylbenzene) with and without magnetic multi-walled carbon nanotubes. Enantiomeric separation of propranolol took place by cyclodextrin-modified capillary electrophoresis and the method was validated in spiked human urine samples. Recovery values raised when styrene/divinylbenzene millimoles ratio was 19.57:15.80. Enrichment factors increased up to approximately 100, detection limits were 13.8 and 10.5 ng ml for R- and S-propranolol respectively, quantitation limits were 46.0 and 34.8 ng ml for R- and S-propranolol respectively, recoveries from spiked samples ranged from 90.9 to 109.0%, and relative standard deviations were <6.3%. This methodology was proven to be more effective th...
Talanta, 2018
A simple, rapid, selective and sensitive monitoring method for the simultaneous determination of ... more A simple, rapid, selective and sensitive monitoring method for the simultaneous determination of the widely-prescribed antidepressants agomelatine, bupropion, citalopram, fluoxetine, mirtazapine, paroxetine, trazodone in just a human blood drop is here developed and validated. This methodology is based on the use of lab manufactured poly(styrene-co-divinylbenzene)-coated glass (PS-DVB) blood spot for the extraction of the analytes and their subsequent separation and detection by capillary liquid chromatography-mass spectrometry (CLC-MS). Briefly, 10 mm-side squares were punched out from blood spots collected on glass substrate coated by 10 µg of the PS-DVB polymer and eluted with 1.0 mL of 2.0% acetic acid in methanol. The analytes were then separated and detected in less than 20 min by capillary CLC-MS using a Jupiter 4 µm Proteo 90 Å column and water: acetonitrile (20:80 v/v) and ammonium acetate (5 mM, pH 3.0) as mobile phase. Limit of detection (LOD) ranged from 0.018 to 0.038 µ...
Electrophoresis, Jan 20, 2018
Poly(styrene-co-divinylbenzene)-coated magnetic multiwalled carbon nanotube composite synthesized... more Poly(styrene-co-divinylbenzene)-coated magnetic multiwalled carbon nanotube composite synthesized by in-situ high temperature combination and precipitation polymerization of styrene-co-divinylbenzene has been employed as a magnetic sorbent for the solid phase extraction of antidepressants in human urine samples. Fluoxetine, venlafaxine, citalopram and sertraline were, afterwards, separated and determined by capillary electrophoresis with diode array detection. The presence of magnetic multiwalled carbon nanotubes in native poly(styrene-co-divinylbenzene) not only simplified sample treatment but also enhanced the adsorption efficiencies, obtaining extraction recoveries higher than 89.5% for all analytes. Moreover, this composite can be re-used at least 10 times without loss of efficiency and limits of detection ranging from 0.014 to 0.041 μg mL were calculated. Additionally, precision values ranging from 0.08 to 7.50% and from 0.21 to 3.05% were obtained for the responses and for the...
Talanta, 2018
Hybrid nanocomposites based on FeOmagnetic nanoparticles (MNPs) coated with different types of ca... more Hybrid nanocomposites based on FeOmagnetic nanoparticles (MNPs) coated with different types of carbon nanotubes (CNTs) have been studied for the first time as sorbent materials for magnetic solid phase extraction (MSPE) for mercury speciation analysis. Monomethylmercury (MMHg) was the target mercury species in water samples and the adsorption and desorption processes were optimized based on this species. Single-walled CNT-MNP showed higher adsorption capacity than double-walled or multi-walled CNTs. Then, the magnetic sorbent was retrieved with an external magnet and MMHg was selectively desorbed from it with dichloromethane (DCM) in two steps with vortex agitation. Inorganic mercury was removed during the desorption stage. The rapid adsorption and desorption equilibrium, the magnetic separation of the sorbent, and the simple and fast synthesis of CNT-MNPs without any additional modification of the CNTs simplified and shortened the extraction procedure. The extract was submitted to ...
Analytical and bioanalytical chemistry, Jan 16, 2017
We propose an alternative approach for the development of analytical methods based on terbium-sen... more We propose an alternative approach for the development of analytical methods based on terbium-sensitized luminescence (TSL). TSL is based on the complexation between Tb(III) ions and fluorescent organic compounds that have appropriate functional groups to complex with Tb(III). We report the use of graphene quantum dot (GQDs) nanoparticles to improve the sensitivity and selectivity of TSL detection. GQDs can react with terbium ions through the carboxylic groups present in their structure. These Tb(III)-GQD complexes, formed in situ in aqueous solution, can be used as time-resolved luminescent probes. Ascorbic acid was selected as a target analyte to demonstrate the suitability of the proposed method. The selectivity of the TSL method was highly improved for most of the interferences tested. Under the optimum conditions [Tb(III) concentration 5 × 10-4 mol L-1, GQD concentration 4 mg L-1], a minimum 100% increase in selectivity was observed for several vitamins and common cations that ...
Journal of Pharmaceutical Analysis
Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment, Jan 8, 2017
Fe3O4 magnetic nanoparticles, with a negative charge surface, are known to have efficient adsorbe... more Fe3O4 magnetic nanoparticles, with a negative charge surface, are known to have efficient adsorbent properties, but they tend to be agglomerated into larger aggregates or flocs, which can cause loss of specific area. The addition of cotton fibre, as a stabiliser in preparation of the Fe3O4 nanoparticles, is able to efficiently reduce particle aggregation, and thus, effective particle size, resulting in much greater specific surface area and adsorption sites. Fe3O4 nanoparticles synthesis was accomplished by in situ high-temperature decomposition of the precursor ferric ion in the presence of cotton fibre and ethylene glycol solvent. The morphology of Fe3O4 nanoparticles was characterised by field emission scanning electron microscopy and X-ray diffraction, which confirmed that the magnetic nanoparticles are highly dispersed. These Fe3O4 nanoparticles were used for clean-up and pre-concentration of Sudan dyes in chilli and hot red sauces, prior to their determination by capillary liq...
Talanta, 2016
An analytical methodology based on coupling reversed-phase liquid chromatography (HPLC) to an ind... more An analytical methodology based on coupling reversed-phase liquid chromatography (HPLC) to an inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the characterization and identification of gold nanoparticles (AuNPs) and gold dissolved species (Au(3+)) in culture medium (Dulbecco&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s Modified Eagle Medium, DMEM) and HeLa cells (a human cervical adenocarcinoma cell line) used in nanotoxicity tests. The influence of the culture medium was also studied and the method applied for nanotoxicity tests. It was also observed that AuNPs can undergo an oxidation process in the supernatants and only a small amount of AuNPs and dissolved Au(3+) was associated with cells. To evaluate the biological impact of AuNPs, a classical viability assay onto HeLa cells was performed using cellular media DMEM in the presence of increasing dosage of 10nm AuNPs. The results showed that 10nm AuNPs exhibit a slight toxic effect.
Fresenius' Journal of Analytical Chemistry, 2000
European Respiratory Journal, Sep 1, 2012
European Respiratory Journal, Sep 1, 2011
Hypothesis: Advanced stage in lung cancer is associated to increased CRP levels in serum. Objecti... more Hypothesis: Advanced stage in lung cancer is associated to increased CRP levels in serum. Objective: To compare blood levels of different inflammatory markers (TNFα, IL-8, C Reactive Protein [CRP] in patients with different stages of lung cancer. Method: 56 patients diagnosed of lung cancer were included (53 males, 64,59±9,73 years, X±SD). All of them underwent studies for disease staging, including fiberbronchoscopy and computed tomography, and positron emission tomography (PET) if indicated. Serum CRP levels were determined by nephelometry and TNFa and IL-8 by ELISA. Results: A significant correlation between staging and serum CRP (r=0.44,p<0.01) was observed. Patients in which CRP levels were higher than 40 mg/L were more likely to have metastatic disease (stage IV) with a specificity of 100%, sensitivity of 44,44%, positive predictive value of 100% and negative predictive value of 76,74%. TNFα and IL-8 were not associated with lung cancer staging. Conclusions: Serum CRP levels higher than 40 mg/L are associated to metastatic disease in non small cell lung cancer.
European Respiratory Journal, Sep 1, 2011
Revista Rol De Enfermeria, 2012
Accredit Qual Assur, 2001
Sensors and Actuators B: Chemical, 2016
Journal of AOAC INTERNATIONAL
After a brief introduction to the generic aspects of automation in analytical laboratories, the d... more After a brief introduction to the generic aspects of automation in analytical laboratories, the different approaches to quality in analytical chemistry are presented and discussed to establish the following different facets emerging from the combination of quality and automation: automated analytical control of quality of products and systems; quality control of automated chemical analysis; and improvement of capital (accuracy and representativeness), basic (sensitivity, precision, and selectivity), and complementary (rapidity, cost, and personnel factors) analytical features. Several examples are presented to demonstrate the importance of this marriage of convenience in present and future analytical chemistry.
The Modern Language Journal
This study investigated the concept of corrective feedback in second language learning as a learn... more This study investigated the concept of corrective feedback in second language learning as a learning resource, recasting it as feedback-seeking behavior. Dweck's (1999) mindsets, Korn and Elliot's (2016) achievement goals, and Ashford's (1986) model of feedback-seeking behavior were re-operationalized in the context of language learning. Questionnaire data from 287 college students studying foreign languages in the United States confirmed that learners make calculated decisions regarding whether to seek feedback, by what method, and from what source, based on their own perceptions of the costs and values associated with different feedback-seeking strategies, which are, in turn, largely predicted by the learners? language mindsets and achievement goals. Learners with a growth language mindset and development-approach goals sought feedback using both monitoring and inquiry methods and from teachers and others. Learners with a fixed language mindset and demonstration goals sought feedback only by method of inquiry but from different sources depending on the valence (approach vs. avoidance) of their goals.
Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment, Jan 26, 2018
A simple and rapid microextraction procedure is reported on the use of ionic liquid in combinatio... more A simple and rapid microextraction procedure is reported on the use of ionic liquid in combination with magnetic nanocellulose hybrid nanoparticles. The procedure is ultrasound-assisted and applicable to selective preconcentration of neonicotinoid insecticides from milk samples, prior to being analysed by liquid chromatography-mass spectrometry. The extraction procedure uses small volume of organic solvents (<1 mL), and there is no need for centrifugation. In the experimental approach the ionic liquid was quickly disrupted by an ultrasonic probe and dispersed in milk samples in a cloudy form. At this stage, neonicotinoid insecticides were extracted into the fine droplets of ionic liquid. Then small amounts of magnetic nanocellulose hybrid nanoparticles were dispersed into the sample solutions to adsorb the ionic liquid containing the analytes and phase separation was completed. The ionic liquid allowed the microextraction of the analytes and a small volume of acetonitrile was use...
Bioanalysis, 2018
The preparation of magnetic multi-walled carbon nanotube poly(styrene-co-divinylbenzene) for prop... more The preparation of magnetic multi-walled carbon nanotube poly(styrene-co-divinylbenzene) for propranolol magnetic solid-phase extraction is described. A study comparing propranolol adsorption and desorption was performed with only magnetic multi-walled carbon nanotubes, and different poly(styrene-co-divinylbenzene) with and without magnetic multi-walled carbon nanotubes. Enantiomeric separation of propranolol took place by cyclodextrin-modified capillary electrophoresis and the method was validated in spiked human urine samples. Recovery values raised when styrene/divinylbenzene millimoles ratio was 19.57:15.80. Enrichment factors increased up to approximately 100, detection limits were 13.8 and 10.5 ng ml for R- and S-propranolol respectively, quantitation limits were 46.0 and 34.8 ng ml for R- and S-propranolol respectively, recoveries from spiked samples ranged from 90.9 to 109.0%, and relative standard deviations were <6.3%. This methodology was proven to be more effective th...
Talanta, 2018
A simple, rapid, selective and sensitive monitoring method for the simultaneous determination of ... more A simple, rapid, selective and sensitive monitoring method for the simultaneous determination of the widely-prescribed antidepressants agomelatine, bupropion, citalopram, fluoxetine, mirtazapine, paroxetine, trazodone in just a human blood drop is here developed and validated. This methodology is based on the use of lab manufactured poly(styrene-co-divinylbenzene)-coated glass (PS-DVB) blood spot for the extraction of the analytes and their subsequent separation and detection by capillary liquid chromatography-mass spectrometry (CLC-MS). Briefly, 10 mm-side squares were punched out from blood spots collected on glass substrate coated by 10 µg of the PS-DVB polymer and eluted with 1.0 mL of 2.0% acetic acid in methanol. The analytes were then separated and detected in less than 20 min by capillary CLC-MS using a Jupiter 4 µm Proteo 90 Å column and water: acetonitrile (20:80 v/v) and ammonium acetate (5 mM, pH 3.0) as mobile phase. Limit of detection (LOD) ranged from 0.018 to 0.038 µ...
Electrophoresis, Jan 20, 2018
Poly(styrene-co-divinylbenzene)-coated magnetic multiwalled carbon nanotube composite synthesized... more Poly(styrene-co-divinylbenzene)-coated magnetic multiwalled carbon nanotube composite synthesized by in-situ high temperature combination and precipitation polymerization of styrene-co-divinylbenzene has been employed as a magnetic sorbent for the solid phase extraction of antidepressants in human urine samples. Fluoxetine, venlafaxine, citalopram and sertraline were, afterwards, separated and determined by capillary electrophoresis with diode array detection. The presence of magnetic multiwalled carbon nanotubes in native poly(styrene-co-divinylbenzene) not only simplified sample treatment but also enhanced the adsorption efficiencies, obtaining extraction recoveries higher than 89.5% for all analytes. Moreover, this composite can be re-used at least 10 times without loss of efficiency and limits of detection ranging from 0.014 to 0.041 μg mL were calculated. Additionally, precision values ranging from 0.08 to 7.50% and from 0.21 to 3.05% were obtained for the responses and for the...
Talanta, 2018
Hybrid nanocomposites based on FeOmagnetic nanoparticles (MNPs) coated with different types of ca... more Hybrid nanocomposites based on FeOmagnetic nanoparticles (MNPs) coated with different types of carbon nanotubes (CNTs) have been studied for the first time as sorbent materials for magnetic solid phase extraction (MSPE) for mercury speciation analysis. Monomethylmercury (MMHg) was the target mercury species in water samples and the adsorption and desorption processes were optimized based on this species. Single-walled CNT-MNP showed higher adsorption capacity than double-walled or multi-walled CNTs. Then, the magnetic sorbent was retrieved with an external magnet and MMHg was selectively desorbed from it with dichloromethane (DCM) in two steps with vortex agitation. Inorganic mercury was removed during the desorption stage. The rapid adsorption and desorption equilibrium, the magnetic separation of the sorbent, and the simple and fast synthesis of CNT-MNPs without any additional modification of the CNTs simplified and shortened the extraction procedure. The extract was submitted to ...
Analytical and bioanalytical chemistry, Jan 16, 2017
We propose an alternative approach for the development of analytical methods based on terbium-sen... more We propose an alternative approach for the development of analytical methods based on terbium-sensitized luminescence (TSL). TSL is based on the complexation between Tb(III) ions and fluorescent organic compounds that have appropriate functional groups to complex with Tb(III). We report the use of graphene quantum dot (GQDs) nanoparticles to improve the sensitivity and selectivity of TSL detection. GQDs can react with terbium ions through the carboxylic groups present in their structure. These Tb(III)-GQD complexes, formed in situ in aqueous solution, can be used as time-resolved luminescent probes. Ascorbic acid was selected as a target analyte to demonstrate the suitability of the proposed method. The selectivity of the TSL method was highly improved for most of the interferences tested. Under the optimum conditions [Tb(III) concentration 5 × 10-4 mol L-1, GQD concentration 4 mg L-1], a minimum 100% increase in selectivity was observed for several vitamins and common cations that ...
Journal of Pharmaceutical Analysis
Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment, Jan 8, 2017
Fe3O4 magnetic nanoparticles, with a negative charge surface, are known to have efficient adsorbe... more Fe3O4 magnetic nanoparticles, with a negative charge surface, are known to have efficient adsorbent properties, but they tend to be agglomerated into larger aggregates or flocs, which can cause loss of specific area. The addition of cotton fibre, as a stabiliser in preparation of the Fe3O4 nanoparticles, is able to efficiently reduce particle aggregation, and thus, effective particle size, resulting in much greater specific surface area and adsorption sites. Fe3O4 nanoparticles synthesis was accomplished by in situ high-temperature decomposition of the precursor ferric ion in the presence of cotton fibre and ethylene glycol solvent. The morphology of Fe3O4 nanoparticles was characterised by field emission scanning electron microscopy and X-ray diffraction, which confirmed that the magnetic nanoparticles are highly dispersed. These Fe3O4 nanoparticles were used for clean-up and pre-concentration of Sudan dyes in chilli and hot red sauces, prior to their determination by capillary liq...
Talanta, 2016
An analytical methodology based on coupling reversed-phase liquid chromatography (HPLC) to an ind... more An analytical methodology based on coupling reversed-phase liquid chromatography (HPLC) to an inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the characterization and identification of gold nanoparticles (AuNPs) and gold dissolved species (Au(3+)) in culture medium (Dulbecco&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s Modified Eagle Medium, DMEM) and HeLa cells (a human cervical adenocarcinoma cell line) used in nanotoxicity tests. The influence of the culture medium was also studied and the method applied for nanotoxicity tests. It was also observed that AuNPs can undergo an oxidation process in the supernatants and only a small amount of AuNPs and dissolved Au(3+) was associated with cells. To evaluate the biological impact of AuNPs, a classical viability assay onto HeLa cells was performed using cellular media DMEM in the presence of increasing dosage of 10nm AuNPs. The results showed that 10nm AuNPs exhibit a slight toxic effect.
Fresenius' Journal of Analytical Chemistry, 2000
European Respiratory Journal, Sep 1, 2012
European Respiratory Journal, Sep 1, 2011
Hypothesis: Advanced stage in lung cancer is associated to increased CRP levels in serum. Objecti... more Hypothesis: Advanced stage in lung cancer is associated to increased CRP levels in serum. Objective: To compare blood levels of different inflammatory markers (TNFα, IL-8, C Reactive Protein [CRP] in patients with different stages of lung cancer. Method: 56 patients diagnosed of lung cancer were included (53 males, 64,59±9,73 years, X±SD). All of them underwent studies for disease staging, including fiberbronchoscopy and computed tomography, and positron emission tomography (PET) if indicated. Serum CRP levels were determined by nephelometry and TNFa and IL-8 by ELISA. Results: A significant correlation between staging and serum CRP (r=0.44,p<0.01) was observed. Patients in which CRP levels were higher than 40 mg/L were more likely to have metastatic disease (stage IV) with a specificity of 100%, sensitivity of 44,44%, positive predictive value of 100% and negative predictive value of 76,74%. TNFα and IL-8 were not associated with lung cancer staging. Conclusions: Serum CRP levels higher than 40 mg/L are associated to metastatic disease in non small cell lung cancer.
European Respiratory Journal, Sep 1, 2011
Revista Rol De Enfermeria, 2012
Accredit Qual Assur, 2001
Sensors and Actuators B: Chemical, 2016