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1.
Cureus ; 16(4): e57480, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38707098

RESUMO

OBJECTIVE: To determine the factors that might limit Hispanic patients from participating in dermatological clinical trials. METHODS: From January 2022 to July 2022, we administered a 31-item, in-person questionnaire to patients recruited in the waiting area of the Caridad Center, one of the largest free clinics in the United States with a predominately Hispanic population, and a nearby private primary care clinic. RESULTS: Overall, Hispanic patients agreed significantly more with statements in the domain of attitude and behavioral beliefs compared to non-Hispanic survey respondents. The Hispanic ethnicity was associated with increased odds of agreeing with the following statements: "My community would really benefit from skin cancer clinical trials" (OR=0.52; 95% CI 0.30, 0.92), "My participation in a skin cancer study would be very good" (OR=0.59; 95% CI 0.35, 0.99), and "I like to do good for others" (OR=0.41; 95% CI 0.22, 0.77). CONCLUSION: While the United States population is composed of 18.5% Hispanics, they only account for 1% of patients enrolled in clinical trials. This study helps identify potential motivational factors for Hispanic patients to participate in skin cancer clinical trials.

4.
Salud UNINORTE ; 38(2)mayo-ago. 2022.
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1536799

RESUMO

Objetivo: Describir las intervenciones de enfermería en pacientes con trombolisis en ictus isquémico para reducir el riesgo de hemorragia. Metodología: Investigación secundaria, revisión; integrativa. Se realizó una pregunta con la estrategia PICO: ¿Cuáles son las intervenciones de enfermería en pacientes con trombolisis en ictus isquémico para reducir el riesgo de hemorragia antes, durante y después de trombolizar al paciente? Se construyó una ecuación de búsqueda utilizando booleanos, DeCS/MeSH para facilitar la búsqueda en bases de datos. Los artículos encontrados fueron leídos críticamente y clasificados por nivel de evidencia y grados de recomendación. Estudio sin riesgo ético por ser de tipo documental. Se respetaron los derechos de autor de acuerdo con la Ley 44 de 1993. Resultados: Con las 14 unidades de análisis finales fueron construidos 3 dominios que realzan la importancia de los conocimientos y el actuar del personal de enfermería en la reducción del riesgo de hemorragia en pacientes con ictus isquémico. Dichos dominios son: 1) control y monitorización de la tensión arterial; principal cuidado de enfermería antes, durante y después de la trombolisis, 2) terapia combinada; disminución de riesgos hemorrágicos - aumento de la ventana terapéutica, 3) dosificación segura de alteplasa en situaciones contraindicadas. Conclusiones: La intervención de enfermería más significativa durante esta terapia es la monitorización y control de las cifras tensionales, debido a que su aumento mayor a 185/110 mmHg es el factor de riesgo más significativo en la aparición de hemorragias.


Objective: Describe nursing interventions in patients with thrombolysis in ischemic stroke to reduce the risk of bleeding. Methodology: Secondary research, type of review; integrative. A question was asked with the PICO strategy: What are the nursing interventions in patients with thrombolysis in ischemic stroke to reduce the risk of bleeding before, during, and after thrombolyzing the patient? A search equation was constructed using Boolean, DeCS / MeSH to facilitate database searching. The articles were critically read and classified by level of evidence and degrees of recommendation. Study without ethical risk because it is documentary type, copyright was respected according to Law 44 of 1993. Results: With the 14 final analysis units, 3 domains were constructed that highlight the importance of knowledge and the actions of the nursing staff in reducing the risk of bleeding in patients with ischemic stroke. These domains are: 1) control and monitoring of blood pressure; main nursing care before, during, and after thrombolysis, 2) combined therapy; decreased bleeding risks - increased therapeutic window, 3) safe dosage of alteplase in contraindicated situations. Conclusions: The most significant nursing intervention during this therapy is the monitoring and control of blood pressure figures, since and increase larger than 185/110 mmHg is the most significant risk factor in the appearance of bleeding.

5.
Talanta ; 232: 122440, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34074425

RESUMO

A headspace solid-phase microextraction (HS-SPME) method was developed using the metal-organic framework (MOF) CIM-80(Al) as extraction phase and in combination with gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of 6 methylsiloxanes and 7 musk fragrances in different environmental waters. The chromatographic separation was optimized in different GC instruments equipped with different detectors, allowing the correct separation and identification of the compounds. The HS-SPME method was optimized using a Box-Behnken experimental design, while the validation was carried out together with the most suitable commercial fiber (divinylbenzene/polydimethylsiloxane) for comparison purposes. The MOF-based coating was particularly efficient for the determination of volatile methylsiloxanes, showing moderately lower limits of detection (of 0.2 and 0.5 µg L-1versus 0.6 µg L-1 for cyclic methylsiloxanes) and slightly better precision (relative standard deviation values lower than 17% versus 22%) than the commercial coating, while avoiding the cross-contamination issues associated to the polymeric composition of commercial fibers. The method was applied for the analysis of seawater and wastewater samples, allowing the quantification of several analytes and the assessment of matrix effects. The proposed HS-SPME method using the CIM-80(Al) fiber constitutes a more environmentally friendly, simpler, and efficient strategy in comparison with other sample preparation methods using different extraction techniques, while the use of a MOF as fiber sorbent constitutes a potential alternative to exploit the features of SPME for the challenging environmental monitoring of these compounds.

6.
BMJ Open ; 11(3): e041625, 2021 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-33737421

RESUMO

OBJECTIVE: The current study aims to demonstrate independent associations between social, educational and health practice interventions as determinants of exclusive breastfeeding in an urban Ecuadorian population. DESIGN: Prospective survival analyses. SETTING: Ecuadorian mother-child dyads in urban settings. PARTICIPANTS: We followed-up 363 mother-baby dyads who attended healthcare centres in Portoviejo, province of Manabi, for a median time (P25-P75) of 125 days (121-130 days). MAIN OUTCOME MEASURES: We performed a survival analysis, by setting the time-to-abandonment of exclusive breastfeeding measured in days of life, that is, duration of exclusive breastfeeding, periodically assessed by phone, as the primary outcome. Crude and adjusted mixed-effects Cox proportional hazards model were performed to estimate HRs for each explanatory variable. RESULTS: The incidence rate of abandonment of breastfeeding was 8.9 per 1000 person-days in the whole sample. Multivariate analysis indicated the three most significant protective determinants of exclusive breastfeeding were (a) sessions of prenatal breastfeeding education with an HR of 0.7 (95% CI: 0.5 to 0.9) per each extra session, (b) self-perception of milk production, with an HR of 0.4 (95% CI: 0.3 to 0.6) per each increase in the perceived quantity of milk production and (c) receiving early skin-to-skin contact with an HR of 0.1 (95% CI: <0.1 to 0.3) compared with those not receiving such contact, immediately after birth. CONCLUSIONS: Prenatal education on breastfeeding, self-perception of sufficient breast-milk production and early skin-to-skin contact appear to be strong protectors of exclusive breastfeeding among urban Ecuadorian mother-baby dyads.


Assuntos
Aleitamento Materno , Mães , Feminino , Humanos , Lactente , Gravidez , Modelos de Riscos Proporcionais , Estudos Prospectivos , População Urbana
7.
Anal Chim Acta ; 1133: 137-149, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-32993866

RESUMO

A new solid-phase microextraction (SPME) fiber coating was prepared by the immobilization of the metal-organic framework (MOF) CIM-80(Al) on nitinol wires by a green in situ growth approach, using an aqueous synthetic approach, and without the need of any additional material to ensure the attachment of the MOF to the nitinol support. The coating was used for the development of headspace (HS) and direct immersion (DI) SPME methods in combination with gas chromatography and mass spectrometry (GC-MS) for the determination of polycyclic aromatic hydrocarbons (PAHs) as model compounds. Both methods were optimized and validated using the MOF-based fiber together with the commercial polydimethylsiloxane (PDMS) fiber. The MOF extraction phase exhibited superior analytical performance for most of the PAHs in HS-SPME mode (and particularly for less volatiles), while the PDMS fiber presented better results in the DI-SPME method. The analytical performance of the MOF sorbent coating in HS- and DI-SPME methods was also evaluated in urine and brewed coffee samples, without requiring any pretreatment step apart from dilution for DI-SPME experiments, thus showing suitability of the novel coatings for the analysis of complex samples. The proposed CIM-80(Al) fiber was efficient and biocompatible (for using a low cytotoxic sorbent and a biocompatible core support), and it also demonstrated stability and robustness, with inter-fiber (and inter-day) relative standard deviation values lower than 19%, and reusability for more than 80 extraction cycles using 280 °C as desorption temperature.


Assuntos
Estruturas Metalorgânicas , Hidrocarbonetos Policíclicos Aromáticos , Microextração em Fase Sólida , Poluentes Químicos da Água , Café , Cromatografia Gasosa-Espectrometria de Massas , Imersão , Hidrocarbonetos Policíclicos Aromáticos/análise , Urina , Água , Poluentes Químicos da Água/análise
8.
Talanta ; 215: 120910, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32312454

RESUMO

Chemical vapor deposition of MOFs (MOF-CVD) has been used to coat solid-phase microextraction (SPME) fibers with ZIF-8, by exposing ZnO layers to the linker vapor (2-methylimidazole). This ZIF-8 coating has been used as a seed layer in a following solvothermal MOF growth step in order to increase the ZIF-8 thickness. The combined MOF-CVD and solvothermal growth of ZIF-8 on the fibers result in a thickness of ~3 µm, with adequate thermal stability, and mechanical integrity when tested with methanol and acetonitrile ultrasonic treatments. The fibers have been evaluated in direct immersion mode using gas chromatography and flame ionization detection (GC-FID), for a group of target analytes including three polycyclic aromatic hydrocarbons (PAHs) and five personal care products (PCPs). The optimized conditions of the SPME-GC-FID methods include low amount of aqueous sample (5 mL), stirring for 45 min at 35 °C, and desorption at 280 °C for 5 min. The method presents limits of detection down to 0.6 µg L-1; intra-day, inter-day and inter-batch relative standard deviation values lower than 16%, 19%, and 23%, respectively; and a lifetime higher than 70 cycles.

9.
J Chromatogr A ; 1619: 460910, 2020 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-32008827

RESUMO

A pH-sensitive polymer based on the poly(styrene-alt-maleic anhydride) co-polymer serves as basis to develop a microextraction method (pH-HGME) in direct combination with high-performance liquid chromatography (HPLC) and fluorescence detection (FD) for the determination of seven organic compounds, including three polycyclic aromatic hydrocarbons (PAHs), three monohydroxylated PAHs and one alkylphenol, in urine. The method bases on the structural modification of the pH-sensitive polymer in the aqueous sample at a high pH value, followed by the formation and insolubilization of a hydrogel containing the preconcentrated analytes by decreasing the pH, and the direct injection of the hydrogel-rich phase in the HPLC-FD system. The optimization of the main variables permitted the selection of low amounts of aqueous sample (10 mL), which was mixed with 10 mg of co-polymer also present in a low volume (150 µL) of concentrated NaOH. The method further requires the addition of 200 µL of concentrated HCl, 3 min of stirring, and 15 min of centrifugation. This pH-HGME-HPLC-FD method presented low limits of detection, ranging from 0.001 µg L-1 to 0.09 µg L-1 in ultrapure water, average relative recoveries of 96.9% for the concentration level of 0.60 µg L-1, and enrichment factors between 1.50 and 17.7. The proposed method also exhibited high precision, with intermediate relative standard deviations lower than 16% for a concentration level of 0.60 µg L-1. The developed pH-HGME-HPLC-FD method performed adequately when analyzing two human urine samples provided by a non-smoker male and a smoker female, respectively. One of the target analytes (2-hydroxynaphthalene) was quantified in both samples using the standard addition method, with a predicted concentration of 7.3 ± 0.4 µg L-1 in the non-smoker male urine and 19.3 ± 0.6 µg L-1 in the smoker female urine.


Assuntos
Cromatografia Líquida de Alta Pressão , Microextração em Fase Líquida/métodos , Maleatos/química , Hidrocarbonetos Policíclicos Aromáticos/urina , Poliestirenos/química , Feminino , Fluorescência , Humanos , Concentração de Íons de Hidrogênio , Masculino , Fenóis/urina , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação
12.
Rev. colomb. radiol. ; 31(4): 5469-5472, dic. 2020.
Artigo em Inglês, Espanhol | LILACS, COLNAL | ID: biblio-1343724

RESUMO

El tumor desmoplásico de células pequeñas y redondas (TDCPR) es una neoplasia maligna rara, con curso clínico agresivo y mortalidad elevada. Se presenta el caso de un hombre de 21 años de edad, quien consultó por dolor abdominal de intensidad moderada, irradiado al flanco derecho, fiebre y pérdida de peso. En tomografía abdominal con medio de contraste se documentó una gran masa intraperitoneal con áreas de necrosis central y extensión a la pelvis, además de lesiones hepáticas de aspecto neoplásico secundario. El diagnóstico se confirmó mediante biopsia percutánea guiada por ultrasonido, que mostró extensa infiltración por tumor maligno, constituido por células con núcleos vesiculosos de cromatina clara, citoplasma eosinófilo e inmunohistoquímica compatible con dicho tumor. En este artículo se hace una confrontación del caso con los hallazgos descritos en otras series publicadas en la literatura y una revisión clínica del tema.


Desmoplastic small round cell tumor (DSRCT) is a rare malignant neoplasm with an aggressive clinical course and high mortality. The case of a 21-year-old man is presented, who consulted for abdominal pain of moderate intensity radiating to the right flank, fever and weight loss. Contrast abdominal tomography was performed, documenting a large intraperitoneal mass with areas of central necrosis and extension to the pelvis, in addition to secondary neoplastic liver lesions. The diagnosis was confirmed by ultrasound-guided percutaneous biopsy, which reported extensive infiltration by malignant tumor, consisting of cells with vesicular nuclei of clear chromatin, eosinophilic cytoplasm and immunohistochemistry compatible with said tumor. This case report is compared with the findings described in other series published in the literature and a clinical review of the subject is made.


Assuntos
Tumor Desmoplásico de Pequenas Células Redondas , Diagnóstico por Imagem , Neoplasias Abdominais
13.
Sci Total Environ ; 668: 1055-1063, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31018447

RESUMO

New adjuvant formulations, based on proteoliposomes <40 nm and cochleates <100 nm, without Al(OH)3 adjuvant, were evaluated regarding their ability to generate Th1 immune response through a Delayed -Type Hypersensitivity Test, at the mouse model, by using a Neisseria meningitidis B protein complex as antigen. The formulations were administered by intramuscular (IM) (2 inoculations - at baseline and after 14 days) and intranasal (IN) (3 inoculations at 7 days) immunization pathways. All IM immunized groups were able to induce similar response to these formulations as well as to VA-MENGOC-BC® vaccine - containing Al(OH)3 adjuvant (used as positive control of the trial). In all groups, the induced inflammation (IP) rate was statistically higher than in the negative control group (CN) (p < 0.05). Immunogenicity, measured by HSR and CD4+ lymphocyte increase was equivalent to the control vaccine and most important, granuloma reactogenicity at the site of injection was eliminated, fact demonstrated by histological study. All groups of animals immunized by IN route showed HSR reactions and statistically significant differences with respect to the CN group. However, IP values were lower, with statistical differences (p < 0.05) for the same adjuvant formulation IM administered, except the AIF2-nCh formulation that generated statistically similar induction (p > 0.05) by both immunization pathways, suggesting it to be the best candidate for the next IN trial. Proteoliposome and cochleate formulations tested were able to mount potent Th-1 immune response, equivalent to the original vaccine formulation, with the advantage of less reactogenicity in the site of the injection, caused by the toxicity of Al(OH)3 adjuvant gel.


Assuntos
Adjuvantes Imunológicos/uso terapêutico , Antígenos de Bactérias/imunologia , Imunidade Celular , Meningite Meningocócica/prevenção & controle , Vacinas Meningocócicas , Adjuvantes Imunológicos/administração & dosagem , Administração Intranasal , Animais , Injeções Intramusculares , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Neisseria meningitidis , Proteolipídeos
14.
Breast Cancer Res Treat ; 173(2): 439-445, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30315436

RESUMO

PURPOSE: Clinical breast examination (CBE) is an important step in the assessment of patients with breast-related complaints. We developed a standardized simulation and multimedia-based (SSMBI) curriculum using current evidenced-based recommendations. This study aimed to determine if SSMBI training resulted in better performance (examination scores and detection of abnormal findings) than the traditional teaching method. METHODS: Novice fourth-year medical students were exposed to the SSMBI curriculum (n = 68) or traditional (n = 52) training. The traditional group was taught by a lecture and attending weekly clinics where they had hands-on experience. The SSMBI group underwent a structured lecture followed by an instructional video and dedicated simulated teaching. Both groups were assessed through a written knowledge exam and an objective structured clinical examination (OSCE). Student's t test and χ2 tests were used to assess differences in CBE technique and knoweldge. RESULTS: Students who underwent SSMBI training had significantly higher numbers of correct answers describing the different steps and justifications of CBE. OSCE performance was significantly higher in the SSMBI group. SSMBI-trained students were more likely to complete all the necessary CBE steps compared to traditionally-trained students (88.2% vs. 28.2%, p < 0.00001). The SSMBI group was also more systematic and more likely to perform adequate inspection, palpation, examination of the nipple-areolar complex, and identify and characterize a palpable lesion (p < 0.05). CONCLUSIONS: Formal SSMBI training is an important asset when teaching medical students how to perform a CBE. Real clinical experience is still necessary to refine this skill and the physician-patient interaction.


Assuntos
Neoplasias da Mama/diagnóstico , Currículo , Multimídia , Palpação/métodos , Treinamento por Simulação/métodos , Desempenho Acadêmico/estatística & dados numéricos , Competência Clínica , Educação Médica , Feminino , Humanos , Estudantes de Medicina/estatística & dados numéricos
15.
J Chromatogr A ; 1559: 102-111, 2018 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-28487122

RESUMO

The IL-based surfactant octylguanidinium chloride (C8Gu-Cl) was designed and synthetized with the purpose of obtaining a less harmful surfactant: containing guanidinium as core cation and a relatively short alkyl chain. Its interfacial and aggregation behavior was evaluated through conductivity and fluorescence measurements, presenting a critical micelle concentration value of 42.5 and 44.6mmolL-1, respectively. Cytotoxicity studies were carried out with C8Gu-Cl and other IL-based and conventional surfactants, specifically the analogue 1-octyl-3-methylimidazolium chloride (C8MIm-Cl), and other imidazolium- (C16MIm-Br) and pyridinium- (C16Py-Cl) based surfactants, together with the conventional cationic CTAB and the conventional anionic SDS. From these studies, C8Gu-Cl was the only one to achieve the classification of low cytotoxicity. An in situ dispersive liquid-liquid microextraction (DLLME) method based on transforming the water-soluble C8Gu-Cl IL-based surfactant into a water-insoluble IL microdroplet via a simple metathesis reaction was then selected as the extraction/preconcentration method for a group of 6 personal care products (PCPs) present in cosmetic samples. The method was carried out in combination with high-performance liquid chromatography (HPLC) and diode array detection (DAD). The method was properly optimized, requiring the use of only 30µL of C8Gu-Cl for 10mL of aqueous sample with a NaCl content of 8% (w/v) to adjust the ionic strength and pH value of 5. The metathesis reaction required the addition of the anion exchange reagent (bis[(trifluoromethyl)sulfonyl]imide - 1:1 molar ratio), followed by vortex and centrifugation, and dilution of the final microdroplet up to 60µL with acetonitrile before the injection in the HPLC-DAD system. The optimum in situ DLLME-HPLC-DAD method takes ∼10min for the extraction step and ∼22min for the chromatographic separation, with analytical features of low detection limits: down to 0.4µgL-1; high reproducibility: with RSD values lower than 10% (intra-day) and 16% (inter-day) for a spiked level of 15µgL-1; and an average enrichment factor of 89. The requirement of low volumes (30µL) of a low cytotoxic IL-based surfactant allows the method to be considered less harmful than other common analytical microextraction approaches.


Assuntos
Guanidina/química , Líquidos Iônicos/química , Microextração em Fase Líquida/métodos , Animais , Linhagem Celular , Cromatografia Líquida de Alta Pressão , Cosméticos/análise , Química Verde , Líquidos Iônicos/toxicidade , L-Lactato Desidrogenase/metabolismo , Limite de Detecção , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Reprodutibilidade dos Testes , Tensoativos/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação
17.
Diversitas perspectiv. psicol ; 13(2): 187-199, jul.-dic. 2017. tab
Artigo em Espanhol | LILACS | ID: biblio-953070

RESUMO

Resumen Este artículo parte de la reflexión acerca de la vulneración de derechos de las personas con discapacidad, al desconocer que la sexualidad y afectividad también son fundamentales en sus vidas y configuran el ejercicio de los derechos sexuales y reproductivos; sin embargo, se han logrado importantes avances para su reconocimiento como sujetos titulares de derechos y generado múltiples normas que reivindican su titularidad y garantía; no obstante, estudios adelantados en Colombia y en el mundo, evidencian la persistencia de barreras fundamentadas en el desconocimiento, discriminación y falsas creencias sobre dichos aspectos de las personas con discapacidad. El interés del estudio fue indagar mediante una encuesta, los conocimientos, actitudes y prácticas de padres, madres y cuidadores de adolescentes con discapacidad cognitiva de una institución educativa especializada de Bogotá, para que los resultados contribuyan a fortalecer capacidades de las familias y de instituciones con acciones pedagógicas que fomenten la garantía de derechos y el mejoramiento de la calidad de vida de esta población.


Abstract This article starts from the reflection that there is violation of the rights of people with disabilities, not knowing that sexuality and affectivity are also fundamental in their lives and make up the exercise of Sexual and Reproductive Rights; however, significant progress has been achieved for its recognition as rights holders and generated multiple norms that claim for ownership and guarantee of them; nevertheless, advanced studies in Colombia and in the world, evidence the persistence of barriers based on lack of awareness, discrimination and false beliefs about these aspects of people with disabilities. The interest of the study was to investigate through a survey by the knowledge, attitudes and practices of parents and caregivers of teenagers with cognitive disabilities of a specialized educational institution of Bogotá so that the results contribute to strengthen the abilities of the families and the institutions with pedagogical actions that promote the guarantee of rights and the improvement of the quality of life of this population.

18.
Environ Technol ; 38(6): 718-729, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27384382

RESUMO

The environmental monitoring of trihalomethanes (THMs) has been performed by setting up a dispersive liquid-liquid microextraction method in combination with gas chromatography (GC)-mass spectrometry (MS). The optimized method only requires ∼26 µL of decanol as extractant solvent, dissolved in ∼1 mL of acetone (dispersive solvent) for 5 mL of the environmental water containing THMs. The mixture is then subjected to vortex for 1 min and then centrifuged for 2 min at 3500 rpm. The microdroplet containing the extracted THMs is then sampled with a micro-syringe, and injected (1 µL) in the GC-MS. The method is characterized for being fast (3 min for the entire sample preparation step) and environmentally friendly (low amounts of solvents required, being all non-chlorinated), and also for getting average relative recoveries of 90.2-106% in tap waters; relative standard deviation values always lower than 11%; average enrichment factors of 48-49; and detection limits down to 0.7 µg·L-1. Several waters: tap waters, pool waters, and wastewaters were successfully analyzed with the method proposed. Furthermore, the method was used to monitor the formation of THMs in wastewaters when different chlorination parameters, namely temperature and pH, were varied.


Assuntos
Desinfecção , Monitoramento Ambiental/métodos , Cromatografia Gasosa-Espectrometria de Massas , Microextração em Fase Líquida , Trialometanos/análise , Poluentes Químicos da Água/análise , Purificação da Água , Halogenação , Solventes/análise
19.
Environ Technol ; 38(7): 911-922, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27892815

RESUMO

A simple and efficient method has been developed for the extraction and determination of 16 common volatile halogenated disinfection by-products (DBPs) (four trihalomethanes, six haloacetonitriles, and six halonitromethanes) in blending desalinated waters, using headspace solid-phase microextraction and gas chromatography with flame ionization detector (HS-SPME/GC-FID). After the optimization using factorial designs of the HS-SPME parameters (optimum: carboxen/polydimethylsiloxane such as fiber, extraction time of 60 min at 30°C, pH 7, addition of 40% (w/v) of sodium chloride, and desorption time of 2 min at 250°C), quantification limits ranged from 3.03 to 40.8 µg L-1, and relative standard deviation (inter-day) were lower than 9.7% for all the target DBPs. Adequate relative recoveries (with the exception of chloronitromethane) were obtained even when spiking waters at low levels (25 µg L-1), with values between 83.1% and 119% for ultrapure water, and between 87.4% and 115% for blending desalinated waters, supporting in this way the applicability of the method. The influence of various dechlorinating agents on the stability of 16 DBPs in water was evaluated, with ammonium chloride being the most suitable inhibitor of residual chlorine and carrying out the analytical determination of DBPs within 48 h after sampling. Different blending desalinated water samples collected in the South of Tenerife Island (Spain) were successfully analyzed.


Assuntos
Cromatografia Gasosa/métodos , Nitrogênio/química , Microextração em Fase Sólida/métodos , Trialometanos/química , Desinfecção/métodos , Espanha
20.
Anal Chim Acta ; 934: 106-13, 2016 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-27506350

RESUMO

This work describes the applicability of magnetic ionic liquids (MILs) in the analytical determination of a group of heavy polycyclic aromatic hydrocarbons. Three different MILs, namely, benzyltrioctylammonium bromotrichloroferrate (III) (MIL A), methoxybenzyltrioctylammonium bromotrichloroferrate (III) (MIL B), and 1,12-di(3-benzylbenzimidazolium) dodecane bis[(trifluoromethyl)sulfonyl)]imide bromotrichloroferrate (III) (MIL C), were designed to exhibit hydrophobic properties, and their performance examined in a microextraction method for hydrophobic analytes. The magnet-assisted approach with these MILs was performed in combination with high performance liquid chromatography and fluorescence detection. The study of the extraction performance showed that MIL A was the most suitable solvent for the extraction of polycyclic aromatic hydrocarbons and under optimum conditions the fast extraction step required ∼20 µL of MIL A for 10 mL of aqueous sample, 24 mmol L(-1) NaOH, high ionic strength content of NaCl (25% (w/v)), 500 µL of acetone as dispersive solvent, and 5 min of vortex. The desorption step required the aid of an external magnetic field with a strong NdFeB magnet (the separation requires few seconds), two back-extraction steps for polycyclic aromatic hydrocarbons retained in the MIL droplet with n-hexane, evaporation and reconstitution with acetonitrile. The overall method presented limits of detection down to 5 ng L(-1), relative recoveries ranging from 91.5 to 119%, and inter-day reproducibility values (expressed as relative standard derivation) lower than 16.4% for a spiked level of 0.4 µg L(-1) (n = 9). The method was also applied for the analysis of real samples, including tap water, wastewater, and tea infusion.


Assuntos
Líquidos Iônicos/química , Microextração em Fase Líquida , Hidrocarbonetos Policíclicos Aromáticos/análise , Fenômenos Magnéticos , Estrutura Molecular , Solventes/química
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