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1.
Front Psychol ; 15: 1346751, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38655220

RESUMEN

Regardless of where they are, humans are inherently human. In this study, we explore the relationship between compassion, mindfulness, and servant leadership contributing to an overall feeling of safety. Adopting a humanistic approach to human resource management, we examine how compassion and mindfulness intersect under the lens of the Conservation of Resources (COR) theory. Our investigation focuses on understanding how servant leadership facilitates the cultivation of mindfulness through compassion. Using structural equation modeling (SEM), we analyze data gathered from 360 workers across diverse occupational sectors. Our findings provide empirical support for the hypothesis that compassion, manifested as a response to suffering, enhances mindfulness levels in the workplace. Specifically, we observe that organizations promoting servant leadership principles are conducive to higher levels of mindfulness among employees. Practically, our study underscores the importance of designing work contexts that prioritize compassion and servant leadership. By doing so, organizations can foster a positive work environment that promotes mindfulness and enhances workplace safety. Our research contributes to the management literature by offering empirical evidence on the role of servant leadership in cultivating compassion and mindfulness, thereby advancing the discourse on workplace safety and organizational well-being.

2.
J Environ Manage ; 278(Pt 1): 111538, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33113392

RESUMEN

Nature-based wastewater treatments are an economic and sustainable alternative to intensive technologies in rural areas, although their efficiency needs to be improved. This study explores technological co-operation between zooplankton (e.g., Daphnia magna) and bacterial and algal biofilms in a 1.5 m3 zooplankton-based reactor for the on-site treatment of secondary urban wastewater. The efficiency of the reactor was evaluated over a 14-month period without any maintenance. The results suggest a low seasonality effect on nutrient polishing (organic matter and nitrogen) and the removal of solids (TSS and turbidity). The best performance, involving a decrease in organic carbon, nitrogen, E. coli loads, and solid content was achieved in winter when operating the reactor at 750 L d-1. Under these conditions, the quality of the effluent water was suitable for its reuse for six different purposes in conformance with Spanish legislation. These results demonstrate that the zooplankton-based reactor presented here can be used as an eco-sustainable tertiary treatment to provide water suitable for reuse. On-site research revealed that the robustness of the reactor against temperature and oxygen fluctuations needs to be improved to ensure good performance throughout the year.


Asunto(s)
Aguas Residuales , Zooplancton , Animales , Biopelículas , Reactores Biológicos , Escherichia coli , Nitrógeno , Eliminación de Residuos Líquidos , Pesos y Medidas
3.
Talanta ; 217: 121005, 2020 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-32498873

RESUMEN

In the present study, we investigated the possibilities and drawbacks of hollow fiber liquid phase microextraction (HF-LPME) combined with total reflection X-ray fluorescence (TXRF) spectrometry for the determination of low amounts of inorganic arsenic (As) species in water samples. The obtained results showed that a three-phase HF-LPME system was more suitable to be used in combination with TXRF than the two phase configuration, since lower detection limit and better precision for As determination can be attained. Relevant experimental parameters affecting As extraction (i.e. types of extractant, organic solvent, agitation speed, pH and extraction time) and TXRF analysis (deposition volume and drying mode) were systematically evaluated. It was found that As(III) was more efficiently extracted at pH 13, whereas, optimum pH for As(V) extraction was at pH 8.5. Limits of detection (LOD) achieved using the best analytical conditions meet the requirements of current legislation and allow the determination of inorganic As(V) and As(III) in water. The proposed method was also applied to different spiked environmental water samples for the preconcentration and subsequent determination of trace inorganic As species.

4.
Chemosphere ; 238: 124683, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31524620

RESUMEN

The combination of the filtration capacity of zooplankton (e.g. Daphnia) with the nutrient removal capacity of bacterial/algal biofilm in a zooplankton-containing reactor could provide a natural-based alternative for wastewater treatment. A laboratory-scale zooplankton-based reactor was tested at different HRTs resulting in a significant reduction in nutrient concentrations in wastewater when the system was operated at HRTs longer than 1.1 days (preferably of between 2 and 4 days). However, the presence of high concentrations of organic matter (>250 mg COD L-1) in the wastewater inhibited zooplankton activity, limiting its use to tertiary treatment. Therefore, in combination with other natural treatments that can perform primary and secondary treatments, zooplankton may provide a solution for wastewater clarification and nutrient polishing. The effect of a common metal such as copper on the filtration capacity of Daphnia was also evaluated. Daphnia, as well as the whole zooplankton-based reactor, adapted to copper concentrations of up to 70 µg Cu L-1 but an overload of 380 µg Cu L-1 for two-weeks severely affected the biological system.


Asunto(s)
Bacterias/metabolismo , Reactores Biológicos , Daphnia/metabolismo , Aguas Residuales/química , Zooplancton/metabolismo , Animales , Biopelículas/crecimiento & desarrollo , Cobre/análisis , Filtración/métodos , Sustancias Húmicas/análisis
5.
J Hazard Mater ; 384: 121201, 2020 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-31586917

RESUMEN

The broad use of silver nanoparticles (AgNPs) in daily life products enhances their possibilities to reach the environment. Therefore, it is important to understand the uptake, translocation and biotransformation in plants and the toxicological impacts derived from these biological processes. In this work, Lactuca sativa (lettuce) was exposed during 9 days to different coated (citrate, polyvinylpyrrolidone, polyethylene glycol) and sized (60, 75, 100 nm) AgNPs at different concentrations (1, 3, 5, 7, 10, 15 mg L-1). Total silver measurements in lettuce roots indicated that accumulation of AgNPs is influenced by size and concentration, but not by nanoparticle coating. On the other hand, nanosilver translocation to shoots was more pronounced for neutral charged and large sized NPs at higher NP concentrations. Single particle inductively coupled plasma mass spectrometry analysis, after an enzymatic digestion of lettuce tissues indicated the dissolution of some NPs. Ag K-edge X-ray absorption spectroscopy analysis corroborated the AgNPs dissolution due to the presence of less Ag-Ag bonds and appearance of Ag-O and/or Ag-S bonds in lettuce roots. Toxicological effects on lettuces were observed after exposure to nanosilver, especially for transpiration and stomatal conductance. These findings indicated that AgNPs can enter to edible plants, exerting toxicological effects on them.


Asunto(s)
Lactuca/efectos de los fármacos , Lactuca/metabolismo , Nanopartículas del Metal/toxicidad , Plata/toxicidad , Transporte Biológico , Carotenoides/metabolismo , Clorofila/metabolismo , Ligandos , Nanopartículas del Metal/química , Tamaño de la Partícula , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Brotes de la Planta/efectos de los fármacos , Brotes de la Planta/metabolismo , Plata/química , Propiedades de Superficie
6.
Anal Bioanal Chem ; 411(20): 5317-5329, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31165186

RESUMEN

The expansion of silver nanoparticle (AgNP) applications in industry as antibacterial agents has generated an increment of their presence in the environment. Once there, their behavior is not clear because they can undergo different transformation processes that affect their transport, mobility, bioavailability, and toxicity. Therefore, the characterization and quantification of these emerging contaminants are important to understand their behavior and the toxicity effects that can be exerted on living beings. Single particle inductively coupled plasma mass spectrometry (SP-ICPMS) has demonstrated its ability to characterize and give quantitative information on AgNPs in aqueous samples. However, sometimes, the discrimination of the signal corresponding to AgNPs from the signal of dissolved species (Ag(I)) is a challenge. In the present contribution, it is shown that the presence of high amounts of Ag(I) hamper silver nanoparticle size and nanoparticle concentration determination in aqueous samples by SP-ICPMS. To facilitate signal discrimination of both chemical forms, the combination of cloud point extraction (CPE) with SP-ICPMS was studied. CPE experimental conditions to separate AgNPs from Ag(I) were assessed and adapted taking into account the characteristics of the SP-ICPMS technique. CPE and soil matrix effects on particle size were evaluated, showing that particle size was not modified after being in contact with soil matrix and after being separated by CPE. Additionally, frequently used calculation methods for SP-ICPMS data treatment were assessed. Finally, the potential of the developed methodology CPE-SP-ICPMS was evaluated in aqueous soil leachates contaminated with mixtures of AgNPs/Ag(I).

7.
J Environ Sci (China) ; 83: 205-216, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31221383

RESUMEN

The production of silver nanoparticles (AgNPs) has increased tremendously during recent years due to their antibacterial and physicochemical properties. As a consequence, these particles are released inevitably into the environment, with soil being the main sink of disposal. Soil interactions have an effect on AgNP mobility, transport and bioavailability. To understand AgNP adsorption processes, lab-controlled kinetic studies were performed. Batch tests performed with five different Mediterranean agricultural soils showed that cation exchange capacity and electrical conductivity are the main parameters controlling the adsorption processes. The adsorption kinetics of different sized (40, 75, 100 and 200 nm) and coated (citrate, polyvinylpyrrolidone and polyethyleneglycol (PEG)) AgNPs indicated that these nanoparticle properties have also an effect on the adsorption processes. To assess the mobility and bioavailability of AgNPs and to determine if their form is maintained during adsorption/desorption processes, loaded soils were submitted to leaching tests three weeks after batch adsorption studies. The DIN 38414-S4 extraction method indicated that AgNPs were strongly retained on soils, and single-particle inductively coupled plasma mass spectrometry confirmed that silver particles maintained their nanoform, except for 100 nm PEG-AgNPs and 40 nm citrate-coated AgNPs. The DTPA (diethylenetriaminepentaacetic acid) leaching test was more effective in extracting silver, but there was no presence of AgNPs in almost all of these leachates.


Asunto(s)
Nanopartículas del Metal/química , Modelos Químicos , Plata/química , Suelo/química , Adsorción , Agricultura , Ácido Cítrico/química , Cinética , Tamaño de la Partícula , Povidona/química
8.
Waste Manag ; 75: 312-318, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29395735

RESUMEN

Sewage sludge is used as a fertilizer replacement in agricultural soils for its chemical properties, such as organic matter content, and for its capability to improve physical soil characteristics like porosity. This is also an appealing disposal option for residue whose production is increasing worldwide. However, there is some concern about the presence of potentially toxic elements (PTEs) that can accumulate in soils and become available for crops. In this work, a study was conducted to evaluate the extractability and crops transfer of thirteen PTEs from soils that had been amended with biosolids each year for 15 years as a regular agricultural practice. The study was conducted with barley (winter cereal) and maize (spring cereal) crops. After this long period, an increase in the amount of Pb, Hg, Zn and Ag in soils amended by biosolids was confirmed. However, it is important to emphasize that the PTE total content in croplands was still far below the thresholds established by US and European regulations. Statistically significant differences were also found between the soils fertilized with biosolids and other treatments compared with the potential phytoavailable amount of Cu, Se, Sb and especially for As and Zn, by a DTPA leaching test. Despite these results, the concentration of PTEs in the barley and maize grains grown in fields repeatedly amended with biosolids was not statistically different from those grown with chemical fertilization, except for As in barley grains. In this case, a significant correlation was found between the DTPA-extractable As content in soils and the total content in grains (r = 0.83).


Asunto(s)
Productos Agrícolas , Fertilizantes , Aguas del Alcantarillado/química , Contaminantes del Suelo , Hordeum , Suelo , Zea mays
9.
Bioelectrochemistry ; 117: 57-64, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28633067

RESUMEN

To date acetate is the main product of microbial electrosynthesis (MES) from carbon dioxide (CO2). In this work a tubular bioelectrochemical system was used to carry out MES and enhance butyrate production over the other organic products. Batch tests were performed at a fixed cathode potential of -0.8V vs SHE. The reproducibility of the results according to previous experiments was validated in a preliminary test. According to the literature butyrate production could take place by chain elongation reactions at low pH and high hydrogen partial pressure (pH2). During the experiment, CO2 supply was limited to build up pH2 and trigger the production of compounds with a higher degree of reduction. In test 1 butyrate became the predominant end-product, with a concentration of 59.7mMC versus 20.3mMC of acetate, but limitation on CO2 supply resulted in low product titers. CO2 limitation was relaxed in test 2 to increase the bioelectrochemical activity but increase pH2 and promote the production of butyrate, what resulted in the production of 87.5mMC of butyrate and 34.7mMC of acetate. The consumption of ethanol, and the presence of other products in the biocathode (i.e. caproate) suggested that butyrate production took place through chain elongation reactions, likely driven by Megasphaera sueciensis (>39% relative abundance). Extraction and concentration of butyrate was performed by liquid membrane extraction. A concentration phase with 252.4mMC of butyrate was obtained, increasing also butyrate/acetate ratio to 16.4. The results are promising for further research on expanding the product portfolio of MES.


Asunto(s)
Reactores Biológicos/microbiología , Ácido Butírico/aislamiento & purificación , Ácido Butírico/metabolismo , Dióxido de Carbono/metabolismo , Electroquímica , Electrodos , Transporte de Electrón
10.
BMJ Case Rep ; 20162016 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-26994057

RESUMEN

We describe cases of two previously healthy women presenting with progressively worsening breathlessness for 1-2 months. In both cases, physical examination was suggestive of a left-sided pleural effusion, confirmed by chest X-ray. Analysis of aspirated fluid showed a lymphocytic exudate, but cytological analysis was negative for malignancy in both patients. CT scan revealed malignancies as the underlying cause of the effusions. Both patients were managed with intercostal drainage in order to collect a sufficient amount of pleural fluid to perform a new technique in our hospital: cell block. This proved to be extremely useful in assessing the definitive diagnosis and management of both women. We briefly discuss the approach to a malignant pleural effusion and the aid of this not-so-new technique.


Asunto(s)
Técnicas Citológicas/métodos , Exudados y Transudados/citología , Cavidad Pleural/patología , Derrame Pleural Maligno/diagnóstico , Adulto , Anciano , Femenino , Humanos , Cavidad Pleural/citología , Derrame Pleural Maligno/citología , Tomografía Computarizada por Rayos X
11.
Appl Spectrosc ; 68(11): 1241-6, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25286343

RESUMEN

The present contribution presents a preliminary investigation of the chemical composition with respect to major, minor, trace, and ultratrace elements in several clam species that are frequently used for human consumption in Portuguese markets and worldwide. In order to use a simple and rapid analytical methodology for clam analysis, energy dispersive X-ray fluorescence (EDXRF) spectrometry and total reflection X-ray fluorescence (TXRF) spectrometry were selected as analytical techniques. The analytical capabilities of TXRF spectrometry were evaluated for the determination of minor and trace elements in commercial edible clams. We compared the direct analysis of powdered suspensions (using different sample amounts and dispersant agents) with the analysis of the digested samples for trace element determination. Inductively coupled plasma mass spectrometry analysis of clam digests was also performed to evaluate the analytical possibilities of TXRF spectrometry for trace and ultratrace analysis.


Asunto(s)
Bivalvos/química , Metales/análisis , Mariscos/análisis , Espectrometría por Rayos X/métodos , Animales , Europa (Continente) , Espectrometría de Masas , Turquía , Vietnam
12.
Sci Total Environ ; 468-469: 804-12, 2014 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-24070874

RESUMEN

Dissolved organic carbon (DOC) and Fe mineral phases are known to influence the mobility of arsenic (As) in groundwater. Arsenic can be associated with colloidal particles containing organic matter and Fe. Currently, no data is available on the dissolved phase/colloidal association of As in groundwater of alluvial aquifers in West Bengal, India. This study investigated the fractional distribution of As (and other metals/metalloids) among the particulate, colloidal and dissolved phases in groundwater to decipher controlling behavior of organic and inorganic colloids on As mobility. The result shows that 83-94% of As remained in the 'truly dissolved' phases (i.e., <0.05 µm size). Strong positive correlation between Fe and As (r(2) between 0.65 and 0.94) is mainly observed in the larger (i.e., >0.05 µm size) colloidal particles, which indicates the close association of As with larger Fe-rich inorganic colloids. In smaller (i.e., <0.05 µm size) colloidal particles strong positive correlation is observed between As and DOC (r(2)=0.85), which highlights the close association of As with smaller organic colloids. As(III) is mainly associated with larger inorganic colloids, whereas, As(V) is associated with smaller organic/organometallic colloids. Scanning Electron Microscopy and Energy Dispersive X-ray spectroscopy confirm the association of As with DOC and Fe mineral phases suggesting the formation of dissolved organo-Fe complexes and colloidal organo-Fe oxide phases. Attenuated total reflectance-Fourier transform infrared spectroscopy further confirms the formation of As-Fe-NOM organometallic colloids, however, a detailed study of these types of colloids in natural waters is necessary to underpin their controlling behavior.


Asunto(s)
Arsénico/análisis , Coloides/química , Agua Potable/química , Agua Subterránea/química , Contaminantes Químicos del Agua/análisis , Arsénico/química , Filtración , India , Hierro/química , Microscopía Electrónica de Rastreo , Tamaño de la Partícula , Espectrometría por Rayos X , Espectrofotometría Atómica , Espectroscopía Infrarroja por Transformada de Fourier
13.
J Chromatogr A ; 1298: 68-75, 2013 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-23755983

RESUMEN

A robust and sensitive analytical method is developed to quantitatively determine tetracyclines and sulfonamides, two major antibiotic classes, in sewage sludge. The antibiotic agents, oxytetracycline, tetracycline, dioxycycline, chlorotetracycline, sulfathiazole, sulfapyridine, sulfamethazine and sulfamethoxazole, were extracted using pressurized liquid extraction (PLE) with citric acid at pH 3 and methanol (1:1 v/v). Clean-up of the extracts was performed by solid phase extraction (SPE) with hydrophilic-lipophilic balance cartridges. Identification and quantification of the compounds is by liquid chromatography-tandem mass spectrometry in multiple reaction monitoring (MRM) mode. High recoveries ranging from 90.4 to 99.9% for sulfonamides and 96.2 to 100.9% for the tetracyclines are obtained. Method detection limits (MDLs) range from 0.6 to 4.2 ng/g for sulfonamides and 3.2 to 13 ng/g for tetracyclines. After validation, the method is applied to the analysis of sludges collected from different WWTPs in Spain.


Asunto(s)
Antibacterianos/análisis , Cromatografía Liquida/métodos , Espectrometría de Masas en Tándem/métodos , Aguas del Alcantarillado/análisis , España , Sulfonamidas/análisis , Tetraciclinas/análisis
14.
Anal Chim Acta ; 786: 8-15, 2013 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-23790285

RESUMEN

In the present study, and taking into account the microanalytical capability of total reflection X-ray spectrometry (TXRF), we explored the possibilities of hollow fibre liquid-phase microextraction (HF-LPME) and dispersive liquid-liquid microextraction (DLLME) combined with TXRF for the determination of low amounts of inorganic Sb species in waters. For each of the LPME configurations aforementioned, experimental parameters affecting Sb extraction but specially the proper sample preparation process (deposition volume on the reflective carrier and drying mode) and measurement conditions for subsequent TXRF analysis have been carefully evaluated. The best analytical strategy for the determination of Sb(III) and Sb(V) in the low µg L(-1) range was found to be the application of the DLLME mode before TXRF analysis. The developed methodology was successfully applied to the determination of inorganic Sb speciation in different types of spiked water samples.


Asunto(s)
Antimonio/análisis , Microextracción en Fase Líquida/métodos , Espectrometría por Rayos X/métodos , Contaminantes Químicos del Agua/análisis , Agua/análisis , Microextracción en Fase Líquida/normas , Espectrometría por Rayos X/normas
15.
J Hazard Mater ; 262: 1167-75, 2013 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-23122734

RESUMEN

Solar Oxidation and Removal of Arsenic (SORAS) is a low-cost non-hazardous technique for the removal of arsenic (As) from groundwater. In this study, we tested the efficiency of natural citric acid sources extracted from tomato, lemon and lime to promote SORAS for As removal at the household level. The experiment was conducted in the laboratory using both synthetic solutions and natural groundwater samples collected from As-polluted areas in West Bengal. The role of As/Fe molar ratios and citrate doses on As removal efficiency were checked in synthetic samples. The results demonstrate that tomato juice (as citric acid) was more efficient to remove As from both synthetic (percentage of removal: 78-98%) and natural groundwater (90-97%) samples compared to lemon (61-83% and 79-85%, respectively) and lime (39-69% and 63-70%, respectively) juices. The As/Fe molar ratio and the citrate dose showed an 'optimized central tendency' on As removal. Anti-oxidants, e.g. 'hydroxycinnamates', found in tomato, were shown to have a higher capacity to catalyze SORAS photochemical reactions compared to 'flavanones' found in lemon or lime. The application of this method has several advantages, such as eco- and user- friendliness and affordability at the household level compared to other low-cost techniques.


Asunto(s)
Arsénico/química , Ácido Cítrico/análisis , Agua Potable/análisis , Tecnología Química Verde/métodos , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos , Antioxidantes/química , Ácido Cítrico/química , Citrus/metabolismo , Agua Subterránea , Concentración de Iones de Hidrógeno , India , Hierro/química , Solanum lycopersicum/metabolismo , Luz Solar , Temperatura , Purificación del Agua/economía
16.
J Sep Sci ; 35(18): 2460-8, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22753317

RESUMEN

This paper presents two procedures for the determination of four selective serotonin reuptake inhibitors (citalopram, paroxetine, fluoxetine, and sertraline) and one metabolite (norfluoxetine) in sewage sludge utilizing three-phase hollow fiber liquid-phase microextraction (HF-LPME). First, direct HF-LPME was used for extraction, clean-up, and preconcentration. The pharmaceuticals were extracted from slurry samples into an organic phase and then back-extracted into an aqueous phase in the lumen of the hollow fiber. Second, a procedure combining pressurized hot water extraction and HF-LPME for clean-up and preconcentration was developed for the same analytes and matrix. The extracts were subsequently analyzed by liquid chromatography-mass spectrometry. For direct HF-LPME, limits of detection were between 1 and 12 ng g(-1) (dry weight) and the relative standard deviation (RSD) values were 3-12%. For the second method, limits of detection were approximately 6 ng g(-1) for all the compounds and RSD values were 8-12%. The methods were validated by comparison of results for the same samples. Sewage sludge from a Swedish wastewater treatment plant was analyzed by both methods; average concentrations were similar for citalopram, paroxetine, and fluoxetine with values of approximately 530, 40, and 200 ng g(-1) , respectively.


Asunto(s)
Microextracción en Fase Líquida , Inhibidores Selectivos de la Recaptación de Serotonina/análisis , Aguas del Alcantarillado/química , Cromatografía Liquida , Citalopram/análisis , Fluoxetina/análogos & derivados , Fluoxetina/análisis , Espectrometría de Masas , Paroxetina/análisis , Porosidad , Sertralina/análisis , Propiedades de Superficie
17.
Talanta ; 85(4): 1941-7, 2011 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-21872042

RESUMEN

The determination of arsenic by inductively coupled plasma mass spectrometry (ICP-MS) in natural waters with high sodium and chloride content has been investigated. The instrument used is equipped with an octopole collision/reaction cell to overcome spectroscopic interferences. Thus, the optimization of collision/reaction gas flow rates is required when using a pressurized cell. A mixture of 2.9 mL min(-1) of H(2) and 0.5 mL min(-1) of He has been found to be suitable for the removal of (40)Ar(35)Cl(+) interference. The effect of the introduction of small amounts of alcohol has also been studied in this work under both vented and pressurized cell conditions. It has been observed that the presence of 4% (v/v) of ethanol or methanol results in an increase in arsenic sensitivity. Moreover, under vented cell conditions the addition of alcohol also decreases the formation of polyatomic interference. However, this decrease is not observed under pressurized cell conditions. Different elements have been studied as possible internal standards for arsenic determination in presence of high amounts of sodium. Good results have been obtained for rhodium and yttrium under both vented and pressurized cell conditions. Although the presence of alcohol in the sample matrix also affects their behaviour, rhodium and yttrium are still the most suitable elements to correct for these matrix effects. Different experimental conditions have been compared for arsenic determination in spiked, certified and natural waters with high sodium and chloride content. The best results have been obtained under pressurized cell conditions, in the presence of ethanol and using rhodium as internal standard.

18.
J Chromatogr A ; 1217(40): 6153-8, 2010 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-20810117

RESUMEN

In this study, a three-phase hollow fiber liquid-phase microextraction (HF-LPME) method combined with liquid chromatography-mass spectrometry was developed for direct determination of four non-steroidal anti-inflammatory drugs (ketoprofen, naproxen, diclofenac and ibuprofen) in sewage sludge. The drugs were extracted from non-spiked and spiked slurry samples with different amounts of sludge into an organic phase and then back-extracted into an aqueous phase held in the lumen of the hollow fiber. High enrichment factors ranging from 2761 to 3254 in pure water were achieved. In sludge samples, repeatability and inter-day precision were tested with relative standard deviation values between 10-18% and 7-15%, respectively. Average concentrations of 29±9, 138±2, 39±5 and 122±7 ng/g were determined in dried sludge from Källby sewage treatment plant (Sweden) for ketoprofen, naproxen, diclofenac and ibuprofen, respectively.


Asunto(s)
Antiinflamatorios no Esteroideos/análisis , Fraccionamiento Químico/métodos , Cromatografía Liquida/métodos , Espectrometría de Masas/métodos , Aguas del Alcantarillado/química , Diclofenaco/análisis , Ibuprofeno/análisis , Cetoprofeno/análisis , Naproxeno/análisis , Reproducibilidad de los Resultados
19.
Appl Spectrosc ; 64(5): 547-51, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20482975

RESUMEN

The determination of hexavalent chromium (Cr(VI)) in cement-related material extracts is frequently monitored in cement industries to comply with the European Directive (2003/53/EC) that limits the use of cements containing more than 2 mg kg(-1) of water-soluble Cr(VI). In the present work, a rapid and simple method for the determination of water-soluble Cr(VI) in clinker samples has been developed. The analytical methodology is based on the combined use of a low cost Cr(VI) isolation procedure using activated layers followed by their analysis using wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry. WDXRF instrumentation is a common tool used for determining the chemical composition of all materials involved in cement production and also for the quality control of the products produced in cement and concrete factories. Therefore, the presented methodology does not imply the use of additional instrumentation in cement-industries laboratories and can be used as a comparative method to the spectrophotometric reference (EN 196-10:2006). The analytical parameters evaluated (selectivity, limit of detection, linearity, and precision) prove to be suitable for the intended purpose, and the methodology has successfully been applied to determine water-soluble Cr(VI) in several clinker samples.


Asunto(s)
Cromo/análisis , Espectrometría por Rayos X/métodos , Cromo/química , Materiales de Construcción/análisis , Residuos Industriales/análisis , Solubilidad
20.
Artículo en Inglés | MEDLINE | ID: mdl-19174589

RESUMEN

The accuracy and precision of lead isotope ratio measurements by quadrupole-based inductively-coupled plalsma-mass spectrometry (ICP-MS) can be limited by any of a number of instrumental factors being mass bias one of the most relevant. Mass bias can be defined as the deviation of measured isotope ratios from the "true value" due to the different transmission of ions according to their masses before the final detection. In the present research, a systematic study aimed at obtaining a more profound insight into to what extent the potential of the ion optic system and gas-filled octapole collision cell influence the mass discrimination in lead isotopic measurements ((206)Pb/(207)Pb, (208)Pb/(207)Pb and (206)Pb/(208)Pb) using ICP-QMS instrumentation was carried out. From the results obtained, it could be concluded that, in most cases, the effect of ion lens potential variation in mass discrimination is not really significant when working in maximum ion intensity regions. On the other hand, the application of pressurized conditions in the octapole collision/reaction cell using He and H(2) as target gases does not lead to an improvement in ion sensitivity but, instead, introduces a significant mass bias effect, particularly when using high He flow rates (6-8 mL min(-1)). In this latter case, the use of Tl as the internal standard ((203)Tl/(205)Tl) proved to be suitable to correct the mass bias drift and the calculated mass discrimination percentage values decreased from 3.61% to 0.33%. The use of the gas-filled octapole collision cell does not lead to an improvement in lead isotope ratio precision compared to vented conditions.

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