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1.
Geriatr Nurs ; 55: 119-129, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37980780

RESUMO

OBJECTIVE: To explore the effectiveness of doll therapy (DT) on behavior, psychology and cognition among older nursing home residents with dementia. METHODS: A systematic review and meta-analysis was conducted. Subgroup analyses were performed to determine whether the intervention characteristics influenced effect sizes. RESULTS: Ten studies met the inclusion criteria and were selected for qualitative and quantitative synthesis. The overall methodological quality was relatively high. DT significantly improved all behaviors [SMD=-0.42, P=0.01], including agitation [SMD=-0.94, P<0.001], apathy, irritability and wandering, and psychological states (i.e., pleasure, anxiety and depression). However, there was no significant difference in the improvement of cognition. Subgroup analyses revealed that the DT process employing empathy dolls and coordinating with caregivers was more beneficial for improving all behaviors (P=0.01; P=0.02). CONCLUSION: DT significantly reduced behavioral and psychological disturbances among older nursing home residents with dementia. Specifically, administering empathy dolls and coordinating with caregivers may be the most appropriate and effective option.


Assuntos
Apatia , Demência , Humanos , Demência/terapia , Demência/psicologia , Cognição , Ansiedade , Casas de Saúde
2.
J Diabetes Res ; 2020: 6062478, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32185236

RESUMO

BACKGROUND: Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy, and nutritional therapy is the basis of GDM treatment. However, the effects of different forms of nutritional supplementation on improving gestational diabetes are uncertain. OBJECTIVE: We conducted a network meta-analysis to evaluate the effects of supplementation with different nutrients on glucose metabolism in women with GDM. METHODS: We conducted a literature search using PubMed, EMBASE, and the Cochrane Library to identify randomized controlled trials (RCTs) comparing the differences between different nutritional strategies in women with GDM. The Cochrane tool was used to assess the risk of bias. Pairwise meta-analysis and network meta-analysis were used to compare and rank the effects of nutritional strategies for the improvement of fasting plasma glucose (FPG), serum insulin, and homeostasis model assessment-insulin resistance (HOMA-IR). RESULTS: We included thirteen RCTs with a total of 754 participants. Compared with placebo, omega-3, magnesium, vitamin D, zinc, and probiotics were more beneficial for improving FPG, serum insulin, and HOMA-IR. Network analysis showed that vitamin D supplementation was superior to omega-3 (-3.64 mg/dL, 95% CI: -5.77 to -1.51), zinc (-5.71 mg/dL, 95% CI: -10.19 to -1.23), probiotics (-6.76 mg/dL, 95% CI: -10.02 to -3.50), and placebo (-12.13 mg/dL, 95% CI: -14.55 to -9.70) for improving FPG. Magnesium supplementation was more beneficial for decreasing serum insulin compared with probiotics (-5.10 µIU/mL, 95% CI: -9.32 to -0.88) and placebo (-7.80 µIU/mL, 95% CI: -9.32 to -0.88) and placebo (-7.80 . CONCLUSION: Vitamin D supplementation significantly reduced FPG and regulated HOMA-IR. Magnesium supplementation was superior in decreasing serum insulin than supplementation with other nutrients. Nutrient supplementation seemed to have an effect on glucose homeostasis maintenance in patients with GDM and may be considered an adjunctive therapy.


Assuntos
Glicemia/metabolismo , Diabetes Gestacional/dietoterapia , Suplementos Nutricionais , Resistência à Insulina/fisiologia , Diabetes Gestacional/sangue , Feminino , Humanos , Insulina/sangue , Metanálise em Rede , Gravidez , Ensaios Clínicos Controlados Aleatórios como Assunto
3.
Anal Bioanal Chem ; 408(23): 6269-81, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27565791

RESUMO

Bacteria or their protein and peptide entity enrichment using biomolecules-functionalized magnetic nanoparticles, and analysis by matrix assisted laser desorption/ionization mass spectrometry (MALDI MS) is a promising technique to analyze microorganisms. High and low molecular weight proteins like penicillin-binding proteins are responsible for final step synthesis of peptidoglycan biosynthesis; those are the target of lactam antibiotics. In this paper, we synthesized magnetic nanoparticles (mag-NPs) and further modified them with 3-aminopropyltriethoxysilane, and then the ß-lactam antibiotic amoxicillin was covalently linked to their surface. ß-Lactam group attributes as penicillin binding proteins (PBPs) in bacteria. Staphylococcus aureus and Escherichia coli were used as model bacteria for enrichment based on the ß-lactam affinity of magnetic nanoparticles, and then the bacteria were easily separated by an external magnet. Several high molecular weight penicillin binding proteins (PBPs) were detected by MALDI MS containing 10(4) and 10(3) colony-forming unit (cfu) per milileter (mL) of S. aureus and E. coli, respectively. In the case of E. coli, higher molecular weight PBPs were observed at 20 to 55 kDa in MALDI mass spectra. However, S. aureus bacteria resulted with femAB operon-based proteins, with molecular weight of 49570.4 Da, by MALDI MS after using amoxicillin functionalized-mag-NPs. The current approach provides an effective bacteria detection and preconcentration method that has high potential in the near future for fast and sensitive diagnosis of pathogenic bacteria infection. Graphical Abstract Schematic for large proteins analysis by MALDI TOF MS (a) mag-NPs and bacterial interaction (b) Penicillin binding proteins trapping by Amox-mag-NPs.


Assuntos
Amoxicilina/química , Proteínas de Bactérias/análise , Escherichia coli/química , Nanopartículas de Magnetita/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Staphylococcus aureus/química , Proteínas de Bactérias/isolamento & purificação , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Humanos , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/isolamento & purificação
4.
Toxicol Appl Pharmacol ; 272(2): 391-8, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-23811332

RESUMO

The water disinfection byproduct bromate (BrO3(-)) produces cytotoxic and carcinogenic effects in rat kidneys. Our previous studies demonstrated that BrO3(-) caused sex-dependent differences in renal gene and protein expression in rats and the elimination of brominated organic carbon in their urine. The present study examined changes in renal cell apoptosis and protein expression in male and female F344 rats treated with BrO3(-) and associated these changes with accumulation of 3-bromotyrosine (3-BT)-modified proteins. Rats were treated with 0, 11.5, 46 and 308 mg/L BrO3(-) in drinking water for 28 days and renal sections were prepared and examined for apoptosis (TUNEL-staining), 8-oxo-deoxyguanosine (8-oxoG), 3-BT, osteopontin, Kim-1, clusterin, and p-21 expression. TUNEL-staining in renal proximal tubules increased in a dose-related manner beginning at 11.5mg BrO3(-)/L in female rats and 46 mg/L in males. Increased 8-oxoG staining was observed at doses as low as 46 mg/L. Osteopontin expression also increased in a dose-related manner after treatment with 46 mg/L, in males only. In contrast, Kim-1 expression increased in a dose-related manner in both sexes, although to a greater extent in females at the highest dose. Clusterin and p21 expression also increased in a dose-related manner in both sexes. The expression of 3-BT-modified proteins only increased in male rats, following a pattern previously reported for accumulation of α-2u-globulin. Increases in apoptosis in renal proximal tubules of male and female rats at the lowest doses suggest a common mode of action for renal carcinogenesis for the two sexes that is independent of α-2u-globulin nephropathy.


Assuntos
Apoptose/efeitos dos fármacos , Bromatos/toxicidade , Carcinógenos Ambientais/toxicidade , Túbulos Renais Proximais/efeitos dos fármacos , Biossíntese de Proteínas/efeitos dos fármacos , Tirosina/análogos & derivados , Poluentes Químicos da Água/toxicidade , Administração Oral , Animais , Relação Dose-Resposta a Droga , Feminino , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , Masculino , Ratos , Ratos Endogâmicos F344 , Caracteres Sexuais , Tirosina/biossíntese
5.
Toxicology ; 300(1-2): 83-91, 2012 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-22699156

RESUMO

Bromate (BrO(3)(-)) is a ubiquitous by-product of using ozone to disinfect water containing bromide (Br(-)). The reactivity of BrO(3)(-) with biological reductants suggests that its systemic absorption and distribution to target tissues may display non-linear behavior as doses increase. The intent of this study is to determine the extent to which BrO(3)(-) is systemically bioavailable via oral exposure and broadly identify its pathways of degradation. In vitro experiments of BrO(3)(-) degradation in rat blood indicate a rapid initial degradation immediately upon addition that is >98% complete at concentrations up to 66µM in blood. As initial concentrations are increased, progressively lower fractions are lost prior to the first measurement. Secondary to this initial loss, a slower and predictable first order degradation rate was observed (10%/min). Losses during both phases were accompanied by increases in Br(-) concentrations indicating that the loss of BrO(3)(-) was due to its reduction. In vivo experiments were conducted using doses of BrO(3)(-) ranging from 0.077 to 15.3mg/kg, administered intravenously (IV) or orally (gavage) to female F344 rats. The variable nature and uncertain source of background concentrations of BrO(3)(-) limited derivation of terminal half-lives, but the initial half-life was approximately 10min for all dose groups. The area under the curve (AUC) and peak concentrations (C(t=5')) were linearly related to IV dose up to 0.77mg/kg; however, disproportionate increases in the AUC and C(t=5') and a large decrease in the volume of distribution was observed when IV doses of 1.9 and 3.8mg/kg were administered. The average terminal half-life of BrO(3)(-) from oral administration was 37min, but this was influenced by background levels of BrO(3)(-) at lower doses. With oral doses, the AUC and C(max) increased linearly with dose up to 15.3mgBrO(3)(-)/kg. BrO(3)(-) appeared to be 19-25% bioavailable without an obvious dose-dependency between 0.077 and 1.9mg/kg. The urinary elimination of BrO(3)(-) and Br(-) was measured from female F344 rats for four days following administration of single doses of 8.1mgKBrO(3)/kg and for 15 days after a single dose of 5.0mgKBr/kg. BrO(3)(-) elimination was detected over the first 12h, but Br(-) elimination from BrO(3)(-) over the first 48h was 18% lower than expected based on that eliminated from an equimolar dose of Br(-) (15.5±1.6 vs. 18.8±1.2µmol/kg, respectively). The cumulative excretion of Br(-) from KBr vs. KBrO(3) was equivalent 72h after administration. The recovery of unchanged administered BrO(3)(-) in the urine ranged between 6.0 and 11.3% (creatinine corrected) on the 27th day of treatment with concentrations of KBrO(3) of 15, 60, and 400mg/L of drinking water. The recovery of total urinary bromine as Br(-)+BrO(3)(-) ranged between 61 and 88%. An increase in the fraction of the daily BrO(3)(-) dose recovered in the urine was observed at the high dose to both sexes. The deficit in total bromine recovery raises the possibility that some brominated biochemicals may be produced in vivo and more slowly metabolized and eliminated. This was supported by measurements of dose-dependent increases of total organic bromine (TOBr) that was eliminated in the urine. The role these organic by-products play in BrO(3)(-)-induced cancer remains to be established.


Assuntos
Bromatos/farmacocinética , Absorção , Administração Oral , Animais , Bromatos/sangue , Bromatos/urina , Relação Dose-Resposta a Droga , Feminino , Meia-Vida , Ratos , Ratos Endogâmicos F344/metabolismo
6.
Anal Bioanal Chem ; 397(6): 2465-76, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20512317

RESUMO

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is challenging when it is directly applied to identify bacteria in water. This study demonstrates a rapid, sensitive, and selective technique for detection of Gram-positive bacteria in water. It involves a combination of membrane filtration (MF) and vancomycin-conjugated magnetite nanoparticles (VNPs) to selectively separate and concentrate Gram-positive bacteria in tap water and reservoir water, followed by rapid analysis of the isolates using whole-cell MALDI-MS. VNPs specifically recognize cells of Gram-positive bacteria, which serves as a basis for affinity capture of target Gram-positive bacteria. A two-step procedure of surface modification of bare magnetite nanoparticles was applied to synthesize VNPs. MF prior to VNP-based magnetic separation can effectively increase the enrichment factor and detection sensitivity and reduce time-consuming culture steps and the matrix effect for analysis of bacteria in MALDI-MS. The enrichment factor for the MF-VNP technique is about 6 x 10(4). A variety of bacteria, including Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, and Enterococcus faecium, were successfully analyzed from aqueous solutions and their mixtures with Gram-negative bacteria. The optimal conditions of the VNP/MALDI-MS technique, including selection of the MALDI matrix, the choice of cell-washing solution, and the VNP concentration, were also investigated. The capture efficiencies of Gram-positive bacteria with VNPs were 26.7-33.3%. The mass variations of characteristic peaks of the captured bacteria were within +/-5 Da, which indicated good reproducibility of the proposed technique. The technique was applied to detect Gram-positive bacteria in tap water and reservoir water with an analysis time of around 2 h. The detection limit for Bacillus cereus, Enterococcus faecium, and Staphylococcus aureus was 5 x 10(2) cfu/ml for 2.0-l water samples.


Assuntos
Bactérias Gram-Positivas/isolamento & purificação , Nanopartículas/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Óxido Ferroso-Férrico , Filtração , Vancomicina , Microbiologia da Água , Abastecimento de Água
7.
Rapid Commun Mass Spectrom ; 23(24): 3983-93, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19918936

RESUMO

Identification of microbial contaminants in drinking water is a challenge to matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) due to low levels of microorganisms in fresh water. To avoid the time-consuming culture step of obtaining enough microbial cells for subsequent MALDI-MS analysis, a combination of membrane filtration and nanoparticles- or microparticles-based magnetic separation is a fast and efficient approach. In this work, the interaction of bacteria and fluidMAG-PAA, a cation-exchange superparamagnetic nanomaterial, was investigated by MALDI-MS analysis and transmission electron microscopy. FluidMAG-PAA selectively captured cells of Salmonella, Bacillus, Enterococcus and Staphylococcus aureus. This capture was attributed to the aggregation of negatively charged nanoparticles on bacterial cell regional surfaces that bear positive charges. Three types of non-porous silica-encapsulated anion-exchange magnetic microparticles (SiMAG-Q, SiMAG-PEI, SiMAG-DEAE) were capable of concentrating a variety of bacteria, and were compared with silica-free, smaller fluidMAG particles. Salmonella, Escherichia coli, Enterococcus and other bacteria spiked in aqueous solutions, tap water and reservoir water were separated and concentrated by membrane filtration and magnetic separation based on these ion-exchange magnetic materials, and then characterized by whole cell MALDI-MS. By comparing with the mass spectra of the isolates and pure cells, bacteria in fresh water can be rapidly detected at 1 x 10(3) colony-forming units (cfu)/mL.


Assuntos
Bactérias/química , Água Doce/microbiologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Bactérias/isolamento & purificação , Resinas de Troca de Cátion/química , Água Doce/química , Magnetismo , Nanopartículas/química
8.
Talanta ; 80(1): 313-20, 2009 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-19782231

RESUMO

Matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) is powerful in characterizing and identifying bacterial isolates. However, sufficient quantities of bacterial cells are required for generating MALDI mass spectra and a procedure to isolate and enrich target bacteria from sample matrix prior to MALDI-MS analysis is often necessary. In this paper, anion-exchange superparamagnetic nanoparticles (NPs), i.e., fluidMAG-DEAE and fluidMAG-Q, were employed to capture Aeromonas, Salmonella, Pseudomonas, Enterococcus, Bacillus, Staphylococcus and Escherichia coli from aqueous solutions and fresh water. The magnetically isolated bacteria were then characterized by whole cell MALDI-MS. The capture efficiency was found to be dependent on bacterial species, medium pH, the functional group and concentration of the NPs. The experimental results demonstrated that fluidMAG-DEAE and fluidMAG-Q were broad spectrum probes for bacteria. Furthermore, both dead and live bacteria could be captured by the NPs, and the live bacteria captured remained viable. Membrane filtration prior to the magnetic isolation could increase enrichment factor and eliminate potential matrix interference. A detection limit of 1 x 10(3)cfu/ml was achieved for the bacteria spiked in tap water and reservoir water, and the analytical time was around 2h.


Assuntos
Bactérias/isolamento & purificação , Magnetismo , Nanopartículas/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Aeromonas hydrophila/isolamento & purificação , Aeromonas hydrophila/ultraestrutura , Resinas de Troca Aniônica/química , Bacillus subtilis/isolamento & purificação , Bacillus subtilis/ultraestrutura , Bactérias/ultraestrutura , Enterococcus/isolamento & purificação , Enterococcus/ultraestrutura , Escherichia coli/isolamento & purificação , Escherichia coli/ultraestrutura , Filtração , Água Doce/microbiologia , Humanos , Microscopia Eletrônica de Transmissão , Pseudomonas aeruginosa/isolamento & purificação , Pseudomonas aeruginosa/ultraestrutura , Reprodutibilidade dos Testes , Salmonella enterica/isolamento & purificação , Salmonella enterica/ultraestrutura , Especificidade da Espécie , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/instrumentação , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/ultraestrutura , Urina/microbiologia , Microbiologia da Água
9.
Rapid Commun Mass Spectrom ; 21(10): 1606-12, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17443488

RESUMO

This paper describes the first approach that simultaneously quantifies four polar, water-soluble organophosphorus herbicides, i.e., glyphosate, glufosinate, fosamine and ethephon, at nanogram levels in environmental waters. The target herbicides were separated completely by ion chromatography (IC) on a polymer anion-exchange column, Dionex IonPac AS16 (4.0 mm x 250 mm), with 30 mM citric acid flowing at 0.70 mL min(-1) as the eluent. On-line inductively coupled plasma mass spectrometry (ICP-MS) using a quadrupole mass spectrometer was employed as a sensitive and selective detector of the effluents. Various parameters affecting the separation and detection were systematically examined and optimized. Detection limits of the herbicides achieved with the proposed IC/ICP-MS method were 1.1-1.4 microg L(-1) (as compound) based on a 500-microL sample injection. Matrix anions, metal ions, phosphate, polyphosphates, non-polar and other polar organophosphorus pesticides showed no interference. The developed method was validated using reservoir water, treated water and NEWater samples spiked at the level of 10-25 microg L(-1) with satisfactory recoveries (95-109%). It is applicable to the simultaneous determination of microg L(-1) concentrations of the herbicides in polluted water.


Assuntos
Herbicidas/análise , Resíduos de Praguicidas/análise , Poluentes Químicos da Água/análise , Água/análise , Aminobutiratos/análise , Calibragem , Carbamatos/análise , Cromatografia por Troca Iônica , Glicina/análogos & derivados , Glicina/análise , Indicadores e Reagentes , Compostos Organofosforados/análise , Padrões de Referência , Espectrometria de Massas por Ionização por Electrospray , Glifosato
10.
J Chromatogr A ; 1100(2): 160-7, 2005 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-16185703

RESUMO

Quantitative determination of trace glyphosate and phosphate in waters was achieved by coupling ion chromatography (IC) separation with inductively coupled plasma mass spectrometry (ICP-MS) detection. The separation of glyphosate and phosphate on a polymer anion-exchange column (Dionex IonPac AS16, 4.0 mm x 250 mm) was obtained by eluting them with 20 mM citric acid at 0.50 mL min(-1), and the analytes were detected directly and selectively by ICP-MS at m/z = 31. Parameters affecting their chromatographic behaviors and ICP-MS characteristics were systematically examined. Based on a 500-microL sample injection volume, the detection limits were 0.7 microgL(-1) for both glyphosate and phosphate, and the calibrations were linear up to 400 microgL(-1). Polyphosphates, aminomethylphosphonic acid (the major metabolite of glyphosate), non-polar and other polar phosphorus-containing pesticides showed different chromatographic behaviors from the analytes of interest and therefore did not interference. The determination was also interference free from the matrix anions (nitrate, nitrite, sulphate, chloride, etc.) and metallic ions. The analysis of certified reference material, drinking water, reservoir water and Newater yielded satisfactory results with spiked recoveries of 97.1-107.0% and relative standard deviations of < or = 7.4% (n = 3). Compared to other reported methods for glyphosate and phosphate, the developed IC-ICP-MS method is sensitive and simple, and does not require any chemical derivatization, sample preconcentration and mobile phase conductivity suppression.


Assuntos
Cromatografia por Troca Iônica/métodos , Glicina/análogos & derivados , Espectrometria de Massas/métodos , Fosfatos/análise , Poluentes Químicos da Água/análise , Glicina/análise , Isoxazóis , Organofosfonatos/análise , Sensibilidade e Especificidade , Tetrazóis , Abastecimento de Água/análise , Glifosato
11.
Anal Bioanal Chem ; 377(4): 740-8, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12920502

RESUMO

Based on selective sorption of bromide, bromoacetic acids (BAA) and bromomethanes on solid-phase extraction (SPE) cartridges, a sensitive and convenient method was developed for the determination of bromate in waters by inductively coupled plasma mass spectrometry (ICP-MS). Dionex OnGuard Ag and reversed-phase (RP) cartridges were tested for retention characteristics for bromide, BAA and bromomethanes. When a sample acidified with nitric acid was passed through an RP cartridge, BAA and bromomethanes were retained, afterwards bromide was absorbed as a precipitate of silver bromide and bromate was unretained when the nearly neutral sample passed a combination of Ag and H cartridges. After SPE pretreatment the recovery of bromate was 96-106%, and bromide remaining in the aqueous phase was found to be less than 0.06 microg L(-1) when the original bromide concentrations were less than 5 mg L(-1). Effectiveness of stacked Ag and H cartridges in removing bromide from chloride-containing samples was also examined. Common cations and other anions did not interfere with bromate determination. The detection limit for bromate is 57 ng L(-1). This method has been applied to analyse waters from various sources, and the recovery of the spiked bromate was in the range of 92-107%.

12.
Anal Bioanal Chem ; 376(2): 236-42, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12690421

RESUMO

Under acidic conditions tellurium(IV) formed a complex with ammonium pyrrolidine dithiocarbamate (APDC). The tellurium(IV) complex was completely retained on a non-polar Isolute silica-based octadecyl (C(18)) sorbent-containing solid-phase extraction (SPE) cartridge, while the uncomplexed Te(VI) passed through the cartridge and remained as a free species in the solution. Only partial Te(IV) was retained on the SPE cartridge for samples without addition of APDC. On the basis of different retention behaviours of the complexed Te(IV) and uncomplexed Te(VI), a simple and highly sensitive method is proposed for the determination of total tellurium and Te(VI) by SPE separation and inductively coupled plasma mass spectrometry (ICP-MS) detection. The Te(IV) concentration was calculated as the difference between total tellurium and Te(VI) concentrations. The detection limit (3 sigma) is 3 ng L(-1) tellurium. Factors affecting the separation and detection of tellurium species were investigated. Coexisting ions did not show significant interferences with the Te(IV)-APDC complex retention and the subsequent ICP-MS detection of Te. The method has been successfully applied to the tellurium speciation analysis in waters with spiked recoveries for Te(IV) and Te(VI) of 86.0-108% and 87.1-97.4%, respectively.


Assuntos
Espectrometria de Massas/métodos , Pirrolidinas/química , Compostos de Amônio Quaternário/química , Telúrio/análise , Telúrio/isolamento & purificação , Tiocarbamatos/química , Sensibilidade e Especificidade , Água/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação
13.
Anal Bioanal Chem ; 374(6): 1141-6, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12458433

RESUMO

A simple and novel flow injection method for the determination of gaseous SO(2) is described based on gas permeation denuder (GPD) online sampling and preconcentration. The GPD is easily prepared with poly(vinylidene) difluoride microporous membrane as gas permeable material and two Perspex blocks with smooth and flat interface and rectangular engraved channels of mirror image. The sample gas is on one side of the membrane and phosphate buffer of pH 7.0 as the absorbing solution is on the other side. Gaseous SO(2) permeates partially through the gas permeable membrane and dissolves in the absorbing solution. After preconcentration for 5.0 or 8.0 min, the solution is injected into the flow of 5.0 x 10(-4) mol L(-1) 5,5'-dithiobis(2,2'-dinitrobenzoic acid) (DTNB) in 0.025 mol L(-1) phosphate buffer. The resulting product formed between DTNB and absorbed SO(2) is spectrophotometrically monitored at 410 nm with a charge coupled device (CCD) fiber optic spectrometer. The calibration graphs for preconcentration of 5.0 and 8.0 min are linear up to 4.0 and 3.2 mg m(-3) with detection limits of 50 and 35 micro g m(-3), respectively. The corresponding analysis speeds are 8.5 and 6 samples h(-1). The method is selective and just suffer from interference of hydrogen sulfide at higher than 1% of SO(2) level (in m/V) with an error >+10%. The assay just uses cheap and common membrane and reagents and shows potential application in the monitoring of atmospheric SO(2).

14.
Analyst ; 127(10): 1380-5, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12430614

RESUMO

A novel and simple method for inorganic antimony speciation is described based on selective solid phase extraction (SPE) separation of antimony(III) and highly sensitive inductively coupled plasma mass spectrometric (ICP-MS) detection of total antimony and antimony(V) in the aqueous phase of the sample. Non-polar SPE cartridges, such as the Isolute silica-based octyl (C8) sorbent-containing cartridge, selectively retained the Sb(III) complex with ammonium pyrrolidine dithiocarbamate (APDC), while the uncomplexed Sb(V) remained as a free species in the solution and passed through the cartridge. The Sb(III) concentration was calculated as the difference between total antimony and Sb(V) concentrations. The detection limit was 1 ng L(-1) antimony. Factors affecting the separation and detection of antimony species were investigated. Acidification of samples led to partial or complete retention of Sb(V) on C8 cartridge. Foreign ions tending to complex with Sb(III) or APDC did not interfere with the retention behavior of the Sb(III)-APDC complex. This method has been successfully applied to antimony speciation of various types of water samples.


Assuntos
Antimônio/análise , Poluentes Químicos da Água/análise , Análise de Injeção de Fluxo , Espectrometria de Massas/métodos
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