Luis Gras- Chemistry
- University of Alicante
Luis Gras
- Chemistry
- University of Alicante
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75
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Publications (75)
Single particle inductively coupled plasma mass spectrometry (spICP-MS) is extensively employed for the characterization of biogenic selenium nanoparticles (SeNPs) produced by mesophilic microorganisms. Nevertheless, because halophilic microorganisms are also well-known to produce SeNPs, further research efforts are required to investigate spICP-MS...
Current sample preparation strategies for nanomaterials (NMs) analysis in soils by means single particle inductively coupled plasma mass spectrometry have significant constrains in terms of accuracy, sample throughput and applicability (i.e., type of NMs and soils). In this work, strengths and weakness of microwave assisted extraction (MAE) for NMs...
Microwave-assisted extraction (MAE) treatments seem to be a promising sample preparation strategy to isolate nanomaterials (NMs) from environmental samples prior to single particle inductively coupled plasma mass (spICP-MS) determination.
It has been reported that volcanoes release several tonnes of mercury per year among other heavy metals through eruptions, fumaroles, or diffuse soil degassing. Since a high percentage of the world's population lives in the vicinity of an active volcano, the aim of this study is to evaluate the accumulation of these metals in the central nervous sy...
Nanomaterials (NMs) characterization by means single particle inductively coupled plasma mass spectrometry (spICP-MS) relies on assessing transport efficiency. To this end, different strategies have been proposed but contradictory reports could...
The number of works devoted to nanomaterials characterization in organic matrices by means spICP-MS grows every year, but limited information is available about the non-spectral interferences generated by this type of matrices. A better understanding of this interference is a prerequisite for developing more robust methodologies and improving spICP...
Single particle inductively coupled plasma mass spectrometry (spICP-MS) has been explored for the determination of metallic nanoparticles (NPs) in air. Different extraction strategies (i.e., direct immersion, hard cap espresso, ultrasound-assisted and microwave-assisted extraction) and extracting solvents (i.e., citric acid, trisodium citrate, pota...
Whey protein (WP) as a dietary supplement for athletes and gym-users is characterized by a content of high-quality amino acids. The benefits of their consumption are well-known and mainly related to the improvements of strength and body composition. Nevertheless, there is a scarce information about the risk associated to their elemental composition...
In the past few years, microwave induced plasma optical emission spectrometry (MIP-OES) has generated great interest as an alternative technique to inductively coupled plasma-based techniques due to its lower operational cost. Since MIP-OES suffers from severe matrix effects due to easily ionizable elements (EIEs) (Na, Ca, etc.), it is unclear whet...
Inductively coupled plasma mass spectrometry (ICP-MS) has been traditionally employed in life sciences for total element content and speciation studies. Nonetheless, using element-tagged antibodies, ICP-MS also serves as a detector for immunoassays thus allowing the determination of organic molecules (i.e. proteins, biomarkers, toxins, etc.) and ce...
In inductively coupled plasma optical emission spectrometry (ICP-OES), the presence of carbon in the matrix strongly affects (positively and negatively) the emission signal of atomic lines. However, the emission signal of ionic lines is mostly unaffected by this concomitant. The goal of this work is to gain insight into the origin of carbon matrix...
High-power microwave induced plasma optical emission spectrometry (MIP-OES) constitutes a serious alternative to inductively coupled plasma optical emission spectrometry (ICP-OES) for elemental analysis. To improve the analytical capabilities of MIP-OES, dispersive liquid-liquid microextraction (DLLME) procedures seems to be, a priori, a very promi...
Fundamental studies about non-spectral interferences in high-power microwave induced plasma optical emission spectrometry (MIP-OES) are very limited so far. The goal of this work is to investigate non-spectral interferences originated by calcium (0.5% w w-1 calcium nitrate), carbon (5.0% w w-1 glycerol) and sulfur (5.0% w w-1 sulfuric acid) matrice...
During mining activities historically developed at Sierra Minera (Cartagena-La Unión, Spain), high amounts of trace elements were discharged to the Mar Menor coastal lagoon mainly through El Beal Wadi. The objective of this study is to establish the role played by the Cymodocea nodosa in the coastal marine dynamics of trace elements at the mouth of...
Wine contains significant amounts of Cd and Pb coming from different contamination sources. The analysis of these elements still means an enormous challenge due to its low concentration levels and the complexity of the wine matrix. Therefore, new highly sensitive analytical methods are currently required. The present work reports a new method based...
Coupling dispersive liquid-liquid micro-extraction (DLLME) to inductively coupled plasma atomic emission spectrometry (ICP-AES) is usually troublesome due to the limited plasma tolerance to the organic solvents usually employed for metal extraction. This work explores different coupling strategies allowing the multi-element determination by ICP-AES...
An inductively coupled plasma mass spectrometry (ICP-MS)-based immunoassay has been developed to quantify aflatoxin M1 (AFM1) at ultra-trace levels in milk samples. AFM1 detection is carried out by means of a competitive immunoassay using secondary biotinylated antibodies and streptavidin-conjugated Au nanoparticles. After acid addition, nanopartic...
OPEMIL is an administration unit that provides assistance, management and processing about
international and national mobility, in-company internships and employability Programmes of the
Faculty of Science, University of Alicante. Related to the mobility area, our aim is to provide
information and advice to students and teachers of the Faculty of S...
El principal objetivo de este proyecto es organizar una serie de actividades que puedan ser de interés general para todos los estudiantes de la Facultad de Ciencias. Estas actividades, ya sean cursos, seminarios o reuniones, tendrán diferentes objetivos: ayudar al estudiante a mejorar su organización y planificación; fomentar los programas de movil...
Implantación de los nuevos Grados, como sustitución de las Licenciaturas en los estudios universitarios, lleva consigo un proceso de Reacreditación, consistente en la revisión de una serie de parámetros de calidad, a realizar una vez terminada su implantación. Este proceso se ha desarrollado en tres ámbitos principales: la Gestión del Título, los R...
RESUMEN Una vez implantado el Grado de Biología, es el momento de hacer una revisión profunda de los resultados obtenidos, con el fin de comprobar si éstos son adecuados para garantizar la continuidad de la impartición del mismo. Esta comunicación se presenta como resultado del trabajo que se está realizando en el seno de la Comisión del Grado en B...
The elemental analysis of Spanish palm dates by inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry is reported for the first time. To complete the information about the mineral composition of the samples, C, H, and N are determined by elemental analysis. Dates from Israel, Tunisia, Saudi Arabia,...
Results of a systematic study concerning non-spectral interferences from sulfuric acid containing matrices on a large number of elements in inductively coupled plasma–mass spectrometry (ICP-MS) are presented in this work. The signals obtained with sulfuric acid solutions of different concentrations (up to 5% w w− 1) have been compared with the corr...
A microwave-based thermal nebulizer (MWTN) has been employed for the first time as on-line preconcentration device in inductively coupled plasma atomic emission spectrometry (ICP-AES). By the appropriate selection of the experimental conditions, the MWTN could be either operated as a conventional thermal nebulizer or as on-line analyte preconcentra...
The influence of the sample introduction system on the signals obtained with different tin compounds in inductively coupled plasma (ICP) based techniques, i.e., ICP atomic emission spectrometry (ICP–AES) and ICP mass spectrometry (ICP–MS) has been studied. Signals for test solutions prepared from four different tin compounds (i.e., tin tetrachlorid...
Repositorio Institucional RUA: http://rua.ua.es/dspace/handle/10045/25861
El objetivo de este estudio es analizar la participación así como el rendimiento académico de los alumnos de la Facultad de Ciencias que han cursado estudios dentro de los programas docentes de movilidad tanto nacionales (programas SICUE y DRAC) como extranjeros (programa ERASMUS y programa de movilidad no europea) durante los 5 últimos cursos acad...
http://library.iated.org/view/MARTINEZESPINOSA2011STU
ISSN: 2340-1079
RESUMEN Se ha llevado a cabo un estudio que ha permitido poner en marcha herramientas de seguimiento de los títulos de grado en la Facultad de Ciencias, de modo que el trabajo coordinado de diferentes redes y comisiones ha permitido, por un lado, establecer un diagnóstico real de la implementación de los títulos de grado en el curso 2010-2011 y la...
A new fully microwave-assisted liquid sample introduction system (MASIS) is presented and evaluated in Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The device employs a single TM010 microwave cavity for the simultaneous aerosol generation and desolvation. The different experimental requirements of both physical processes deman...
Repositorio Institucional RUA: http://hdl.handle.net/10045/19881
Repositorio Institucional RUA: http://hdl.handle.net/10045/19884
The determination of Pb, Se and As in wine has a great interest due to health risks and legal requirements. To perform the analysis of wine, two considerations must be taken into account: (i) the low concentration level of the analytes; and (ii) the risk of interferences due to wine matrix components. The goal of this work is to evaluate electrothe...
Elemental wine analysis is often required from a nutritional, toxicological, origin and authenticity point of view. Inductively coupled plasma based techniques are usually employed for this analysis because of their multi-elemental capabilities and good limits of detection. However, the accurate analysis of wine samples strongly depends on their ma...
Analytical results in inductively coupled plasma atomic emission spectrometry (ICP-AES) strongly depend on the sample introduction system employed. The standard liquid sample introduction system for in ICP-AES consists of a nebulizer that transforms the bulk liquid into an aerosol and a spray chamber that filters it. Several nebulizer based on diff...
Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) technique is widely employed in elemental and multielemental analysis due to its analytical performance: high sensitivity and analysis throughput and low limits of detection. Nevertheless, matrix effects due to the presence of concomitants in real samples are one of the most importan...
Several additives containing heavy metals are usually added to polymers in order to modify their physical properties. Current European directives regulate the elemental composition and limit the daily bioavailability and migration levels of heavy metals (Ba, Cr, Cd, Hg, Pb, As, Sb and Se) in polymeric samples.1,2,3,4 However, the analytical methodo...
In Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), it has been observed that the emission intensity of some atomic lines is enhanced or depressed by the presence of carbon in the matrix. The goal of this work was to investigate the origin and magnitude of the carbon-related matrix effects in ICP-AES. To this end, the influence of...
A re-designed microwave-based thermal nebulizer (MWTN) that overcomes all the drawbacks shown by previous prototypes (i.e. lack of robustness, poor heating efficiency) is presented. The new device employs an optimized TM010 cavity and nozzle design. MWTN performance was evaluated in inductively coupled plasma atomic emission spectrometry (ICP-AES)...
A microwave assisted sample introduction system based on the use of a TM010 cavity (MWDS2) has been employed for the introduction of 10% w/w organic solvent solutions in inductively coupled plasma atomic emission spectrometry (ICP-AES). Ethanol, propan-2-ol, formic and acetic acids have been used. Firstly, the effect of the incident microwave power...
A new microwave assisted desolvation system based on the use of a TM 010 cavity (MWDS2) has been developed and evaluated in plasma based analytical techniques: inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The new design overcomes the main experimental drawbacks shown by...
In this work, a fast and fully automatic microwave assisted chemical oxygen demand (COD) measurement device is described. In this instrument, the absorbance of Cr(III) generated during sample oxidation is measured at 590 nm. Chemical oxygen demand values can be obtained in just 12 min. This represents a significant reduction in digestion time, comp...
A new method for the chemical oxygen demand (COD) determination assisted by ultrasonic radiation has been evaluated for the first time. The suggested method uses an instrumentation simpler and cheaper than the previous ones used for the same purpose. With this preliminary version of the method the optimized experimental conditions are: high ultraso...
Accurate theoretical or semi-empirical characterization of pneumatically generated aerosols in atomic spectrometry is important in order to know the effect of the operating conditions on drop size distribution and aerosol transport phenomena. There are some empirical models for aerosol size prediction that have never been applied in the field of at...
A vertical cyclonic spray chamber/Nafion membrane-based desolvation system was used to eliminate the nitric acid interference in inductively coupled plasma atomic emission spectroscopy (ICP-AES). Three different matrices were studied: plain water and solutions containing 0.9 and 3.6 mol l−1 of nitric acid. The liquid flow rate ranged between 20 and...
A review of elemental matrix effects in ICP AES is presented. Areas covered include: effect of the presence of concomitants; variables affecting the interferences; proposed mechanisms explaining matrix effects; and correction methods. (321 references).
In the present work, the matrix effects observed in ICP-AES with both nitric- and sodium-based solutions have been discussed. Some approaches previously proposed in the literature to mitigate the matrix effects (i.e., the use of a cyclonic spray chamber and the proper selection of plasma conditions) have been adopted in the present study. Therefore...
The combination of an inductively coupled plasma optical emission spectrometer (ICP-OES) based on echelle optics and a segmented charge coupled device detector and electrothermal vaporization sample introduction has been evaluated for survey analysis. The proposed survey analysis method requires a previous selection of a set of elements and the add...
In the present work, the influence of the spray chamber design on the matrix effects was investigated in Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The study was carried out in terms of aerosol drop size distribution and emission signal. Solutions of two inorganic acids and salts were employed to characterize the extent of t...
The behaviour of an infrared desolvation system with acid solutions in inductively coupled plasma atomic emission spectrometry (ICP-AES) is evaluated, and the influence of the liquid uptake rate and of the nature and concentration of the acid on the solvent and analyte transport rates and on the analytical figures of merit is studied. The results a...
The analytical behaviour of an electrothermal vaporization (ETV) device for the introduction of mineral acid solutions in inductively coupled plasma mass spectrometry (ICP-MS) was evaluated. Water, nitric acid, hydrochloric acid, perchloric acid and sulphuric acid in concentrations within the 0.05–1.0 mol l−1 range were studied. For all the acids t...
This study deals with the behaviour of a microwave desolvation system (MWDS) with acid solutions in inductively coupled plasma atomic emission spectrometry. Hydrochloric, nitric, sulphuric and perchloric acids at different concentrations (up to 0.6 mol l−1) have been tested. Sample uptake rate (Ql) was also varied. The parameters evaluated for each...
The idea of heating aerosols by applying a microwave field has recently been taken up again for liquid sample introduction in atomic spectrometry. Heating of the droplets can take place directly, because of microwave energy absorption by the droplets themselves, or indirectly, as a result of heat transmission from the radiated parts of the system t...
The present paper describes the preliminary results obtained with a desolvation system for inductively coupled plasma atomic emission spectrometry that incorporates a heating unit based on microwave (MW) radiation. This system has been called Microwave Desolvation System (MWDS). The results have proved that MW radiation can be considered as a good...
A microwave-based thermal nebulizer (MWTN) has been employed for the first time as on-line preconcentration device in inductively coupled plasma atomic emission spectrometry (ICP-AES). By the appropriate selection of the experimental conditions, the MWTN could be either operated as a conventional thermal nebulizer or as on-line analyte preconcentra...
