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BACKGROUND: Pain management of vaso-occlusive crises is a fundamental priority in the lifelong care of children and adolescents with sickle cell disease. AIM: This study examined nurses' attitudes towards caring for children with sickle cell disease (SCD) and SCD pain management in those with vaso-occlusive pain. METHOD: A structured, self-reporting survey was provided to a convenience sample of 298 nurses across 10 hospitals serving Jordan's northern and middle regions. Descriptive and inferential statistics were applied for data analysis. RESULTS: Most nurses (77%) perceived their experience caring for children with SCD as positive. Many nurses (65%) felt frustrated about caring for these children during painful episodes. Participants identified workload and inadequate time as limiting their ability to address the analgesic needs of children with SCD. Receiving structured education specialized in pain management and more years of experience in nursing significantly predicted less hesitancy in administering opioid-based analgesia. CONCLUSIONS: The results of this study provided further insight into factors that potentially contribute to vaso-occlusive pain crises frequently being poorly managed and inadequately addressed among pediatric patients. Nurses' attitudes and understanding of SCD pain management must be addressed to advance the clinical practice of managing pain in children with SCD.
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Analgesia , Anemia Falciforme , Enfermeiras e Enfermeiros , Adolescente , Humanos , Criança , Estudos Transversais , Jordânia , Analgésicos/uso terapêutico , Dor/tratamento farmacológico , Dor/etiologia , Anemia Falciforme/complicações , Anemia Falciforme/tratamento farmacológicoRESUMO
BACKGROUND: The increasing pressure of their professional duties has led to a notable concern regarding the mounting anxiety levels among nurses. The ongoing discussion revolves around the efficacy of mindfulness as a means to alleviate anxiety in nurses. AIM: This systematic review evaluated the effectiveness of mindfulness in reducing anxiety among nurses. METHODS: The evaluation followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. An extensive and comprehensive search was conducted across eight databases to identify studies that utilized randomized controlled trials (RCTs) and were published in English between 2011 and 2022. Independently, two reviewers assessed the validity of the randomized controlled trials using the Consolidated Standards of Reporting Trials criteria. Additionally, two authors independently employed the Risk of Bias in Non-Randomized Studies of Interventions (ROBINS-2) method to evaluate the potential bias in the RCTs. RESULTS: Eight randomized controlled trial studies that were deemed eligible were included in the current analysis. Based on the literature review, it was determined that mindfulness-based training can assist nurses in reducing their anxiety levels. Furthermore, the effectiveness of mindfulness-based programs in enhancing nurses' mindfulness and self-compassion has been firmly established. LINKING EVIDENCE TO ACTION: Based on existing literature, mindfulness-based interventions have proven to be effective in reducing anxiety levels among nurses. However, in order to enhance the overall quality of research, it is necessary to implement more rigorous controlled designs that include randomization. Additionally, larger sample sizes with a diverse range of participants are needed to establish and validate the effectiveness of mindfulness-based programs in alleviating anxiety among nurses. Implementing mindfulness-based training in healthcare organizations can offer numerous benefits. One such advantage is that it can help nurses in reducing anxiety and enhancing their ability to handle the pressures associated with their profession. STUDY REGISTRATION: PROSPERO Protocol registration ID: CRD42023475157.
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Ansiedade , Atenção Plena , Enfermeiras e Enfermeiros , Humanos , Atenção Plena/métodos , Ansiedade/psicologia , Ansiedade/prevenção & controle , Enfermeiras e Enfermeiros/psicologiaRESUMO
BACKGROUND: The use of mobile health applications (apps) is an effective strategy in supporting patients' self-management of heart failure (HF) in home settings, but it remains unclear whether they can be used to reduce sedentary behaviors and increase overall physical activity levels. AIM: The aims of this study were to determine the effect of an 8-week home-based mobile health app intervention on physical activity levels and to assess its effects on symptom burden and health-related quality of life. METHOD: In this study, we collected repeated-measures data from 132 participants with HF (60.8 ± 10.47 years) randomized into a usual care group (n = 67) or an 8-week home-based mobile health app intervention group (n = 65). The intervention was tailored to decrease the time spent in sedentary behavior and to increase the time spent in physical activities performed at light or greater intensity levels. Physical activity levels were monitored for 2 weeks before the intervention and during the 8-week intervention using the Samsung mobile health app. Heart failure symptom burden and health-related quality of life were assessed at baseline, 2 weeks from baseline assessment, and immediately post intervention. RESULTS: At week 8, all participants in the intervention group demonstrated an increase in the average daily step counts above the preintervention counts (range of increase: 2351-7925 steps/d). Only 29 participants (45%) achieved an average daily step count of 10 000 or higher by week 6 and maintained their achievement to week 8 of the intervention. Repeated-measures analysis of variance showed a significant group-by-time interaction, indicating that the intervention group had a greater improvement in physical activity levels, symptom burden, and health-related quality of life than the usual care group. CONCLUSION: Home-based mobile health app-based interventions can increase physical activity levels and can play an important role in promoting better HF outcomes.
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Insuficiência Cardíaca , Aplicativos Móveis , Telemedicina , Humanos , Qualidade de Vida , Exercício Físico , Insuficiência Cardíaca/terapiaRESUMO
BACKGROUND: Heart failure (HF) is associated with chronic inflammation, which is adversely associated with survival. Although sex-related differences in inflammation have been described in patients with HF, whether sex-related differences in inflammation are associated with event-free survival has not been examined. AIM: The aim of this study was to determine whether the association between inflammation as indicated by tumor necrosis factor-α and event-free survival differs between men and women with HF after controlling for demographic and clinical variables. METHOD: This was a secondary analysis of data from 301 male (age, 61.0 ± 11.4 years) and 137 female (age, 60.3 ± 12.1 years) patients with HF. Serum levels of soluble tumor necrosis factor receptor 1 were used to indicate inflammatory status. Patients were grouped according to median split of soluble tumor necrosis factor receptor 1 level and sex into male with low inflammation (≤1820 pg/mL) (n = 158) or high inflammation (>1820 pg/mL) (n = 143), and female with low inflammation (n = 63) or high inflammation (n = 74). Cox regression models were run separately for men and women to determine whether inflammation contributed to differences in event-free survival between sexes with HF. RESULTS: There were 84 male (27.9%) and 27 female (19.7%) patients who had an event. Event-free survival in women did not differ by the severity of inflammation in the Cox regression analysis. In contrast, men with high inflammation had 1.85 times higher risk for an event compared with men with low inflammation. CONCLUSION: These data provide evidence that inflammation contributed to differences in event-free survival in men but not women with HF. Clinicians should be aware that men who have higher inflammation may be at a greater risk of HF or cardiac-related events than others with HF.
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Insuficiência Cardíaca , Caracteres Sexuais , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Intervalo Livre de Progressão , Intervalo Livre de Doença , Estudos Prospectivos , Inflamação/complicações , Insuficiência Cardíaca/complicaçõesRESUMO
The anticancer activity of terretonin N (1) and butyrolactone I (2), obtained from the thermophilic fungus Aspergillus terreus TM8, was intensively studied against prostate adenocarcinoma (PC-3) and ovary adenocarcinoma (SKOV3) human cell lines. According to this study, both compounds showed potent cytotoxicity towards ovarian adenocarcinoma cells (SKOV3) with IC50 1.2 and 0.6 µg/mL, respectively. With respect to metastatic prostate cells (PC-3), the two compounds 1 and 2 showed a significantly promising cytotoxicity effect with IC50 of 7.4 and 4.5 µg/mL, respectively. The tested fungal metabolites showed higher rates of early and late apoptosis with little or no necrotic apoptotic pathway in all treated prostate adenocarcinoma (PC-3) and ovary adenocarcinoma (SKOV3) human cell lines, respectively. The results reported in this study confirmed the promising biological properties of terretonin N (1) and butyrolactone I (2) as anticancer agents via the induction of cellular apoptosis. However, further studies are needed to elucidate the molecular mechanism by which cellular apoptosis is induced in cancer cells.
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4-Butirolactona/análogos & derivados , Apoptose/efeitos dos fármacos , Aspergillus/química , Neoplasias Ovarianas/patologia , Neoplasias da Próstata/patologia , Terpenos/farmacologia , 4-Butirolactona/química , 4-Butirolactona/farmacologia , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Forma Celular/efeitos dos fármacos , Feminino , Humanos , Concentração Inibidora 50 , Masculino , Terpenos/químicaRESUMO
INTRODUCTION: The mandate of the United Nations Relief and Work Agency in the Near East (UNRWA) includes education and health services of registered Palestinian refugees in Jordan and other countries. UNRWA is facing limited funding because of unstable political circumstances. This review aims to spotlight the importance of UNRWA's role in promoting Palestinian refugees' health inside and outside camps in Jordan. METHOD: This systematic review was conducted through iteratively searching electronic research databases for original, recent, full-text literature regarding the health and social outcomes of Palestinian refugees in Jordan. RESULTS: The 12 reviewed studies showed that UNRWA's programs through its clinics and schools have a crucial role in improving Palestinian refugees' health outcomes such as adolescents' cigarette smoking prevalence, infant mortality, non-communicable disease management, health-related quality of life, mental/psychological health services, and reproductive health. Access to UNRWA's health services may account for better or comparable health outcomes among Palestinian refugees. CONCLUSION: Despite the short funding and political pressures, UNRWA has provided aid and services to Palestinian refugees inside and outside refugee camps in Jordan. UNRWA's role is crucial in maintaining decent health outcomes in this vulnerable, underserved population. The further limiting of UNRWA funding may jeopardize the health of millions.
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Refugiados , Adolescente , Árabes , Humanos , Lactente , Jordânia/epidemiologia , Avaliação de Resultados em Cuidados de Saúde , Qualidade de VidaRESUMO
A monolithic capillary column containing a composite of metal-organic framework MIL-53(Al) incorporated into hexyl methacrylate-co-ethylene dimethacrylate was prepared to enhance the separation of mixtures of small aromatic compounds by using capillary liquid chromatography. The addition of 10 mg/mL MIL-53(Al) microparticles increased the micropore content in the monolithic matrix and increased the Brunauer-Emmett-Teller surface area from 26.92 to 85.12 m(2) /g. The presence of 1,4-benzenedicarboxylate moieties within the structure of MIL-53(Al) as an organic linker greatly influenced the separation of aromatic mixtures through π-π interactions. High-resolution separation was obtained for a series of alkylbenzenes (with resolution factors in the range 0.96-1.75) in less than 8 min, with 14 710 plates/m efficiency for propylbenzene, using a binary polar mobile phase of water/acetonitrile in isocratic mode. A reversed-phase separation mechanism was indicated by the increased retention factor and resolution as the water percentage in the mobile phase increased. A stability study on the composite column showed excellent mechanical stability under various conditions. The higher resolution and faster separation observed at increased temperature indicated an exothermic separation, whereas the negative values for the free energy change of transfer indicated a spontaneous process.
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BACKGROUND: There is a gap in the literature regarding learning outcomes linked to the use of high-fidelity simulators compared to that of traditional teaching methods. AIM: To examine the effect of using high-fidelity simulators on knowledge and skills acquisition and retention with university students. METHODS: A randomized two-arm trial using two different educational approaches on 90 nursing students assigned randomly to two groups was used at two points of time. FINDINGS: The results showed significant differences in favor of the participants in the high-fidelity simulator group on both the acquisition and retention of knowledge and skills over time. However, a significant loss of cardiopulmonary resuscitation knowledge and skills occurred at 3 months after training in both groups. CONCLUSIONS: The findings of this study may assist educators in integrating high-fidelity simulators in education and training. In addition, the findings may help nursing educators to arrange additional cardiopulmonary resuscitation training sessions in order to improve cardiac arrested patients' outcomes. LINKING EVIDENCE TO ACTION: High-fidelity simulation (HFS) provides students with interactive learning experiences in a safe controlled environment. HFS enables teachers to implement critical clinical scenarios, such as cardiac arrest, without risk to patients. Integrating the simulation training into nursing curricula will help to overcome the challenges that face many courses, specifically the shortage of clinical areas for training and the increase in numbers of nursing students.
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Reanimação Cardiopulmonar/educação , Reanimação Cardiopulmonar/enfermagem , Instrução por Computador , Educação em Enfermagem/métodos , Aprendizagem Baseada em Problemas/métodos , Estudantes de Enfermagem/estatística & dados numéricos , Ensino/métodos , Adulto , Competência Clínica , Simulação por Computador , Avaliação Educacional , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Retenção Psicológica , Adulto JovemRESUMO
Polymer monolithic stationary phases were prepared based on a cyclic anhydride as a reactive and tunable platform via ring-opening post-polymerization using primary amines, octadecylamine and benzylamine. The characterization techniques indicated the insertion of the functional groups into the original monoliths and confirmed the amidation reactions. The post-polymerization modification also improved the monolith's thermal and mechanical stability and induced significant improvement in their surface area. The stationary phases were synthesized inside small dimension stainless-steel columns (2.1 mm i.d. × 50 mm length). The prepared columns before and after modifications have been tested for the separation of the alkylbenzene series and some polycyclic aromatic hydrocarbons (PAHs) as model compounds. In all cases, the chromatographic performance in terms of the height equivalent to a theoretical plate on the functionalized monoliths was remarkably improved when compared with that on the unmodified monolith, which was between 9.59-39.49 µm and 4.08-31.50 µm using monoliths modified with octadecylamine and benzylamine, respectively. Under the same chromatographic conditions, the functionalization of monoliths with octadecylamine provided more hydrophobic interactions and enhanced the retention of alkylbenzenes, while the modification of monoliths with benzyl groups improved the separation and the retention of the PAHs through the strong π-π interactions. However, post-modification polymerization with octadecylamine and benzylamine enhanced the separation efficiency of the prepared columns toward all studied compounds. The repeatability of the injections on the same column and the reproducibility of the prepared columns have been studied for some selected parameters and estimated in terms of percent relative standard deviation (%RSD) for some of the studied compounds. The repeatability of the prepared columns was ≤9.42% (n = 5) based on run-to-run injections and ≤9.48% based on day-to-day injections for five successive days. The reproducibility levels, on the other hand, were ≤20.95% for all studied parameters in all cases. To assess their performance for the analysis of real samples, the applicability of the prepared columns was examined for the separation of the active ingredients extracted from some commercial pharmaceutical formulations and for the separation of tea water extract constituents. The validation data show the suitability of the columns for practical use in the routine analysis of these samples.
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Females of some mosquito species are anthropophilic, as they feed on human blood to support egg production and, hence, are forensically valuable if found at a crime scene. The present study investigated the blood meal digestion process in Culex pipiens L. both with and without heroin and proposed a method for estimating the post-feeding interval (PFI). Mosquitoes were fed on a control mouse, a heroin-injected mouse, or in vitro heroin-treated mouse blood. The blood meal digestion was then investigated at different hours post-feeding. Data showed that the blood meal size ingested by control mosquitoes was 0.681â ±â 0.04 mg/mosquito and was completely digested within 45 h post-feeding. An estimation of the PFI was proposed in terms of the rate of hemoglobin (Hb) digestion. The blood meal size of the mosquitoes fed on the in vitro heroin-treated blood and the heroin-injected mouse was 0.96â ±â 0.06 and 0.79â ±â 0.01 mg/mosquito and was completely digested within 50 and 55 h post-feeding, respectively. The digestion of Hb started similarly in all experimental mosquitoes until 10 h post-feeding, after which it significantly decreased in heroin-treated blood meals compared with the control ones. This may suggest that heroin impacted the digestion process, as it took an extra 5-10 h to complete. These findings could be valuable in the forensic context since an estimation of PFI is proposed as a potential estimation of the postmortem interval (PMI). However, care should be taken as heroin in the host blood has significantly impacted the overall digestion process and, hence, may bias the PFI/PMI estimation.
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Culex , Culicidae , Alcaloides Opiáceos , Animais , Feminino , Camundongos , Digestão , Comportamento Alimentar , Heroína , Refeições , Mosquitos VetoresRESUMO
Organic monolithic columns are mainly used to separate macromolecules; however, many attempts to extend their performance toward small molecules were examined by incorporating micro- and nanoparticles. The incorporation technique enabled utilizing organic monoliths in gas chromatography (GC) for small molecules, which are still scarce. Here, we prepared a composite matrix of capillary monolithic columns of a zeolite-like metal-organic framework with a sodalite topology (sod-ZMOF) and Divinylbenzene polymer (DVB) for GC separations under 0.5 MPa. Relatively short DVB monolithic columns (18 cm long × 0.25 mm i.d.) incorporated with a tiny amount of sod-ZMOF nanoparticles (0.7 and 1.17 wt%) with an average particle size of 225 nm were successfully fabricated and used to separate linear alkanes and polar probes mixtures with increasing resolution up to 3.7 and 5.1 times, respectively, compared to a blank DVB monolithic column. A high-performance separation of linear alkanes series mixture (methane to decane) was exhibited in less than 2 min. McReynolds constants revealed that sod-ZMOF provided the composite monolith with a nonpolar character yielding a negative average polarity value smaller than the standard squalene column. An Excellent retention time of pentane and octane day-to-day reproducibility was achieved during 16 days and over more than 500 runs with RSD% of 2.25% and 3.3% using a composite monolithic column with 5 mg mL-1 sod-ZMOF (5-ZMOF@DVB). In addition, a qualitative determination of the gas mixture content of three commercially available Lighter gas cartridges was performed via the 5-ZMOF@DVB column. Finally, successfully separating an azeotropic freon mixture of difluoromethane (R-32) and pentafluoroethane (R-125) was achieved with a selectivity of up to 4.84. A further thermodynamic study related the preferential adsorption of R-125 to entropic factors rather than enthalpic while trapping inside ZMOF pores. This work sheds light on utilizing the infinite diversity of MOFs and combining their properties with high permeability and easily fabricated organic monoliths for GC separations of light molecules and gasses. Furthermore, the study highlights the role of GC as an easy and fast approach for the preliminary evaluation of the separation efficiency of porous polymers.
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Fluorocarbonos , Estruturas Metalorgânicas , Zeolitas , Polímeros/química , Reprodutibilidade dos Testes , Alcanos/análise , Fluorocarbonos/análiseRESUMO
This work relates to the preparation of novel and promising stationary phases containing inorganic-organic composites for capillary liquid and gas chromatography. A naturally occurring montmorillonite was introduced to polymethacrylate monoliths, then used under different conditions of GC and HPLC at the same time. The performance of the columns was evaluated for the separation of alkane and alkylbenzene series in GC and capillary HPLC, respectively. While the bare monoliths failed to separate the model analytes, montmorillonite-based polymethacrylate allowed a full separation of the mixtures with Rs≥1.42. The columns were applied for the determination of myrcene and limonene isomers in the peel extracts of some fruits using GC, and for the analysis of active ingredients including aspirin, vitamin-C, caffeine, and ibuprofen extracted from common drugs using capillary HPLC. In GC, fast separation was achieved in 1.0 min with Rs of 6.53. The columns exhibited the best efficiency for myrcene with 20,900 plates/m. Using the capillary HPLC columns, the active ingredients were resolved in 10 min with Rs≥5.72. The efficiency values located between 12,800-21,700 plates/m in all cases. The developed methods were found to be linear in the range of 0.10-10.0 and 0.20-180 µg/mL for GC and HPLC, respectively. In comparison with commercial columns, the results in GC methods reveal that, despite their much shorter length, the prepared columns proved a faster separation with higher efficiency and comparable detection limits and chromatographic resolution. The prepared HPLC capillaries exposed lower run times and detection limits with comparable efficiency and resolution, and consume fewer samples and mobile phase solvents. The results demonstrate that the montmorillonite-based polymethacrylate composites are applicable as stationary phases for routine analysis and quality control of important fields such as food and pharmaceutical samples.
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Bentonita , Capilares , Cromatografia Gasosa/métodos , Preparações FarmacêuticasRESUMO
This work describes the preparation of polymer based monolithic materials and their use as stationary phases in capillary liquid chromatography. Multi-walled carbon nanotubes (MWCNT) were incorporated into a mixture containing benzyl methacrylate (BMA) and ethylene dimethacrylate (EDMA) as co-monomers. The optimized porogenic mixture was a ternary solution composed of cyclohexanol, 1,4-butandiol and butanol which resulted in a stable and homogeneous suspension. Six capillary columns with increasing amounts of MWCNT, from 0 to 0.4 mg mL(-1), were prepared by thermal polymerization in 0.32 mm (i.d.) and 150 mm length fused silica tubing. The chromatographic evaluation showed that the synthesized monolithic beds were mechanically stable while their porosity and permeability increased with the MWCNT content. The prepared capillary columns were tested for the separation of mixtures of ketones and phenols at an optimum flow rate of 2 µL min(-1). The results showed that incorporation of MWCNT slightly affected the retention while it enhanced the column efficiency by increasing the column efficiency by a factor of up to 9. This effect corresponded also to an improved resolution and full separation of the solutes.
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Metastasis is the major reason for most brain tumors with up to a 50% chance of occurrence in patients with other types of malignancies. Brain metastasis occurs if cancer cells succeed to cross the 'blood-brain barrier' (BBB). Moreover, changes in the structure and function of BBB can lead to the onset and progression of diseases including neurological disorders and brain-metastases. Generating BBB models with structural and functional features of intact BBB is highly important to better understand the molecular mechanism of such ailments and finding novel therapeutic agents targeting them. Hence, researchers are developing novel in vitro BBB platforms that can recapitulate the structural and functional characteristics of BBB. Brain endothelial cells-based in vitro BBB models have thus been developed to investigate the mechanism of brain metastasis through BBB and facilitate the testing of brain targeted anticancer drugs. Bioengineered constructs integrated with microfluidic platforms are vital tools for recapitulating the features of BBB in vitro closely as possible. In this review, we outline the fundamentals of BBB biology, recent developments in the microfluidic BBB platforms, and provide a concise discussion of diverse types of bioengineered BBB models with an emphasis on the application of them in brain metastasis and cancer research in general. We also provide insights into the challenges and prospects of the current bioengineered microfluidic platforms in cancer research.
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This work applies the concepts of green chemistry, where polyethylene terephthalate (PET) bottles were used as the acid-dicarboxylic linker source for the synthesis of MIL-53(Al) metal organic frameworks (MOFs) and then used as a stationary phase for the separation of various solutes and compared with MIL-53(Al) synthesized from traditional terephthalic acid. Both synthesized MIL-53(Al) MOFs were characterized by scanning electron microscopy (SEM), FT-IR, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and specific surface area analysis. Eight groups of standard analytes in addition to real samples were tested to evaluate the separation performance of the MIL-53(Al) packed columns in HPLC under various chromatographic conditions. Based on elution order of the studied compounds and the effects of mobile phase composition, the working mechanism was reversed phase mode in the presence of size-exclusion effects for large molecules, which exceeded the dynamic diameter of MIL-53(Al) (~7.6 Å). The effects of stationary phase sieving, mobile phase flow rate and composition, injected sample mass, and temperature were investigated relative to the chromatographic behavior of MIL-53(Al). MIL-53(Al) particle sieving before packing reduced peak broadening and significantly enhanced the chromatographic performance of the prepared columns up to 2.26 times relative to the number of theoretical plates. The MIL-53(Al) packed columns offered high-resolution separation for all studied mixtures with Rs >2 and good stability and long-term durability. At optimal conditions, the prepared columns exhibited efficiencies between 5600-63200 plates m-1. Higher efficiencies were observed for alkylbenzenes and polyaromatic hydrocarbons as the organic linker in the MIL-53(Al) structure, which improved retention and separation of aromatics through π-π interactions. Thermodynamic parameters including ΔH, ΔS, and ΔG for the transfer of analyte from the mobile phase to the MIL-53(Al) stationary phase were studied. Compared with previously cited MOFs packed columns, the present MIL-53(Al) columns gave comparable selectivity and much better efficiency for most of the studied chemicals at optimum conditions, indicating the feasibility of MIL-53(Al) as a stationary phase for HPLC applications.
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Cromatografia Líquida de Alta Pressão/instrumentação , Química Verde , Estruturas Metalorgânicas/química , Química Verde/tendências , Hidrocarbonetos Aromáticos , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , TermodinâmicaRESUMO
Recently, chromatographic techniques have the potential to be greener in order to reduce the environmental impact. In this work, a new simple, sensitive, efficient, and green analytical method based on UHPLC-MS has been developed for a quick determination of methylxanthines including caffeine, theobromine, and theophylline in tea. Under the optimum conditions, a baseline separation has been achieved within 30 seconds, using isocratic elution consisting of 90% water and only 10% acetonitrile at 0.5 mL/min flow rate (3 mL acetonitrile per hour). The mass spectrometer was operated with the SIR mode in ESI+. The developed method was found to be linear in the range of 0.03-5 µg/mL, with correlation coefficients greater than 0.9995 for the three compounds. The respective values of LOD were found to be 0.025, 0.015, and 0.01 µg/mL for caffeine, theobromine, and theophylline, respectively. The proposed assay was applied to 30 commercial tea samples of different brands. Both caffeine and theobromine were found in all tea samples with maximum concentration in sample no. 15, corresponding to 32.6 and 2.72 mg/g of caffeine and theobromine, respectively. On the contrary, theophylline was not detected at all in most samples. When compared with all previous studies that dealt with the same compounds in different matrices, the developed method was found to be the fastest, allowing high-throughput analyses with more than 100 samples/h. The results prove that the method is suitable for routine analysis of methylxanthines and to distinguish the quality of tea samples of various brands.
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Application of monolithic columns in gas chromatography is still considered very limited. In this work, several polymethacrylate-based monolithic capillary columns were fabricated, characterized and used in gas chromatography. The five monomers used were: methyl methacrylate, (MMA), hexyl methacrylate (HMA), glycidyl methacrylate (GMA), 2-butoxyethyl methacrylate (BEMA) and isobornyl methacrylate (IBMA), while ethylene dimethacrylate was the crosslinker. The monoliths were synthesized in 30â¯cm length capillaries possessing inner diameters (i.d.) of 0.25â¯mm. The prepared monolithic columns were applied for separation of 3 series of homologous alkanes, alcohols and alkylbenzenes, as well as some isomeric mixtures. Van Deemter plots were used to optimize and compare the columns performance. The smaller methacrylates (MMA and GMA) exhibited higher porosity and permeability with low column backpressure values and poorer efficiency than the larger methacrylate monomers (HMA and BEMA). The columns prepared from IBMA monomer showed the highest pressure and the least separation efficiency. The fastest full separation of alkanes was achieved on HMA-co-EDMA column in about 3.0â¯min with resolution better than 2.73, while the fastest full separation of alcohols and alkylbenzenes was carried out using BEMA-co-EDMA column in less than 0.8 and 1.75â¯min with chromatographic resolution better than 1.27 and 1.85, respectively. Again, BEMA-co-EDMA column gave the best performance with the fastest and complete separation of all studied isomeric mixtures. For all tested series of solutes, the better separation efficiency was reached with tridecane, which gave 25,200 plates/m on the HMA-co-EDMA column. Another application was carried out using HMA-co-EDMA column for determination of myrcene and limonene, two monoterpenic isomers, in some fruit peels. Under the optimum GC conditions, a rapid separation of myrcene and limonene was achieved in less than 1.0â¯min with chromatographic resolution of 2.56. The highest contents of myrcene (0.131â¯mg/g) and limonene (1.225â¯mg/g) were measured in the hexane extracts of grapefruit and Egyptian orange, respectively. Finally, a comparison between the prepared columns and a commercial capillary column was performed. Based on the measured run time and HETP values, HMA-co-EDMA and BEMA-co-EDMA monolithic columns exhibited faster separation and higher efficiency for n-alkanes and alkylbenzenes than the TR-5 open tubular column, although they are 100 times shorter.
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Álcoois/análise , Álcoois/isolamento & purificação , Alcanos/análise , Cromatografia Gasosa/métodos , Ácidos Polimetacrílicos/química , Alcanos/isolamento & purificação , Compostos de Epóxi/química , Isomerismo , Metacrilatos/química , PorosidadeRESUMO
Recently, analytical separation techniques have the potential toward green approaches to reduce the environmental impact. This study focuses on the development of an analytical method for the determination of paracetamol and chlorzoxazone in their pharmaceutical combination. The separation was achieved using a home-made capillary column (0.10 mm i.d. × 200 mm length) filled with porous cross-linked hexyl polymethacrylate as monolithic stationary phase. The method proved to be simple, fast, sensitive, efficient, cost-effective and green approach due to the combination of the amazing properties of a monolithic material and a miniaturized liquid chromatography, which would be considered as a step toward reducing the analytical costs and the environmental impact of chromatographic applications. Both components were detected using a 3-nL nano-UV cell fixed at 270 nm wavelength. The optimized mobile phase was composed of 1% aqueous formic acid solution and acetonitrile at 40:60 ratio, 1.0 µL/min flow rate, 4.0 nL injection volume and 50°C column temperature. Under the optimized conditions, paracetamol and chlorzoxazone have been separated in about 6.5 min with chromatographic resolution of 2.37. The prepared column and the analysis method was fully validated and compared with other reported works. All findings allow to conclude that the prepared column and proposed method are applicable for quality control and routine analysis of the two drugs.
Assuntos
Acetaminofen/análise , Clorzoxazona/análise , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia de Fase Reversa/métodos , Ácidos Polimetacrílicos/química , Cromatografia Líquida de Alta Pressão/instrumentação , Cromatografia de Fase Reversa/instrumentação , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , ComprimidosRESUMO
A composite of multi-walled carbon nanotubes incorporated into a benzyl methacrylate-co-ethylene dimethacrylate porous monolith was prepared, characterized and used as solid phase adsorbent and as stationary phase for simultaneous extraction and separation of ten polycyclic aromatic hydrocarbons, followed by nano-liquid chromatography analysis. The extraction and chromatographic parameters were optimized with regard to the extraction efficiency and the quality of chromatographic analytes separation. Under the optimized conditions, all PAHs were separated in 13â¯min with suitable resolution values (Rsâ¯=â¯1.74-3.98). Addition of a small amount of carbon nanotubes (0.1% with respect to monomers) to the polymerization mixture increased the efficiency for the separation column to over 41,700â¯platesâ¯m-1 for chrysene at flow rate of 0.5⯵Lâ¯min-1. The method showed a wide linear range (1-500⯵gâ¯L-1 with R2 more than 0.9938), acceptable extraction repeatability (RSDsâ¯<â¯6.4%, nâ¯=â¯3) and reproducibility (RSDsâ¯<â¯12.6%, five parallel-made solid phase extraction cartridges) and satisfactory detection limits (0.02-0.22⯵gâ¯L-1). Finally, the proposed method was successfully applied to the detection of polycyclic aromatic hydrocarbons in environmental water samples. After a simple extraction procedure with preconcentration factor equal to 100, the average recovery values in ultra-pure, tap and sea water samples were found to be in the range 81.3-95.4% with %RSD less than 6.4. Again, the presence of carbon nanotubes (0.3% relatively to monomers) in native polymer enhanced the extraction performance for the solid phase adsorbent up to 78.4%. The application of the monoliths modified with CNTs in extraction and nano-scale liquid chromatography for analysis of environmental samples offered several advantages; it demonstrated an acceptable precision, low detection limits, good reproducibility, satisfying recoveries and wide dynamic linear ranges.