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1.
J Econ Entomol ; 111(3): 1461-1468, 2018 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-29608742

RESUMO

Sitophilus oryzae (Coleoptera: Curculionidae) and Sitophilus zeamais (Coleoptera: Curculionidae) are major insect pests of farm-stored grains in China. Moreover, their respective distribution and prevalence are not yet assessed for grain storage facilities in China. The two species are often difficult to identify by morphology because they are immature or their presence is only evident from fragments. Species-specific primers were, therefore, designed based on the cytochrome c oxidase subunit I (COI) of 34 populations found throughout China and three foreign populations. Following the validation of this molecular-based approach for species identification, the distribution of the two species in China was determined from 68 different grain storage facilities. The results indicate that S. zeamais is prevalent throughout the country whereas S. oryzae is mainly present in the south and the center of China. It is believed that this distribution pattern is in function of ecological adaptation, mostly determined by temperature and the grain species. This is the first report of its kind, demonstrating the distribution of S. zeamais and S. oryzae in grain storage facilities throughout China and analyzed by species-specific primers of COI.


Assuntos
Distribuição Animal , Grão Comestível , Armazenamento de Alimentos , Gorgulhos/fisiologia , Animais , Sequência de Bases , China , Complexo IV da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Fazendas , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Alinhamento de Sequência , Gorgulhos/genética
2.
Cell Mol Biol (Noisy-le-grand) ; 63(8): 38-41, 2017 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-28886312

RESUMO

To explore the mechanism of psoriasis vulgaris (PV), serum protein expression profiles between PV patients with blood-heat syndrome and healthy volunteers were detected by isobaric tags for relative and absolute quantitation (iTRAQ). First, sera from 15 PV patients with blood-heat syndrome and 10 healthy volunteers were collected; then, serum proteins were separated and hydrolyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and a specific iTRAQ marker enzyme respectively after further purification and protein abundance treatment. Compared with the control group, differentially expressed proteins in PV patients with blood-heat syndrome were identified and analyzed by tandem mass spectrometry. A total of 787 proteins were identified and 718 proteins had a functional annotation with gene ontology (GO) by iTRAQ in the current study. Significant differences (P <0.05) and great differences (P <0.01) were found in 681 proteins and 536 proteins respectively between the patient group and healthy group. ). Different protein expression profiles in serum existed between PV patients with blood-heat syndrome and healthy volunteers; the differences largely involved immune-related proteins and lipoproteins. The proteins specific for PV with blood-heat syndrome deserves further investigation.


Assuntos
Proteínas Sanguíneas/isolamento & purificação , Proteínas do Sistema Complemento/isolamento & purificação , Lipoproteínas/isolamento & purificação , Proteoma/isolamento & purificação , Psoríase/sangue , Adulto , Proteínas Sanguíneas/classificação , Estudos de Casos e Controles , Proteínas do Sistema Complemento/classificação , Biologia Computacional/métodos , Feminino , Ontologia Genética , Humanos , Lipoproteínas/classificação , Masculino , Anotação de Sequência Molecular , Proteoma/classificação , Psoríase/diagnóstico , Espectrometria de Massas em Tandem
3.
Zhonghua Shao Shang Za Zhi ; 33(5): 295-300, 2017 May 20.
Artigo em Chinês | MEDLINE | ID: mdl-28651421

RESUMO

Objective: To explore the effects of change of activity of vacuolar adenosine triphosphatase (V-ATPase) of myocardial lysosome on myocardial damage in rats after severe burn and its mechanism. Methods: The myocardial lysosomes were extracted from the hearts of 12 SD rats with ultra-high speed gradient density centrifugation, then Western blotting and transmission electron microscope observation were conducted for identification. One hundred and twenty rats were divided into pure burn group, ATP group, normal control group, and bafilomycin group according to the random number table, with 30 rats in each group. Rats in pure burn group and ATP group were inflicted with 40% TBSA full-thickness scald on the back. Immediately after injury, rats in pure burn group were intraperitoneally injected with lactated Ringer's solution in 4 mL·%TBSA(-1)·kg(-1,) and rats in ATP group were intraperitoneally injected with ATP in 0.4 mg/kg at 12 h before burn, immediately after burn, and 12 h after burn. Rats in normal control group did not receive any treatment, and rats in bafilomycin group were intraperitoneally injected with bafilomycin A1 in 0.3 mg/kg at the same time points as those of ATP group. At 24 h after burn, 30 rats from each group were collected for determining activity of V-ATPase of myocardial lysosome with coupled-enzyme assay and the expression of myocardium autophagy-related proteins microtubule-associated protein 1 light chain 3 (LC3) and P62 by Western blotting. Left ventricular arterial blood was collected to detect the content of 5 items of myocardial enzyme spectrum and cardiac troponin T (cTnT). Data were processed with one-way analysis of variance and t test. Results: (1) After identification, both the expression level of lysosome-related membrane protein 1 and purity of lysosome in the sample were high, and the structure of lysosome was intact. (2) At 24 h after burn, the activity values of V-ATPase of myocardial lysosome in rats of pure burn group, ATP group, normal control group, and bafilomycin group were (2.03±0.67), (3.01±0.58), (4.29±0.26), and (1.83±0.52) µmol·mg(-1)·h(-1,) respectively. The activity value of V-ATPase of myocardial lysosome in rats of pure burn group was significantly lower than the values in ATP group and normal control group (with t values respectively 3.14 and 8.87, P values below 0.01). The activity values of V-ATPase of rats in normal control group were significantly higher than those in bafilomycin group (t=11.87, P<0.01). At 24 h after burn, the expressions of myocardial LC3 and P62 in pure burn group were significantly higher than those in ATP group and normal control group (with t values from 3.73 to 5.88, P values below 0.01). The expressions of myocardial LC3 and P62 in normal control group were significantly lower than those in bafilomycin group (with t values respectively 2.64 and 3.07, P<0.05 or P<0.01). At 24 h after burn, the content of 5 items of myocardial enzyme spectrum and cTnT in pure burn group was significantly higher than that in ATP group and normal control group (with t values from 3.24 to 16.72, P values below 0.01). The content of 5 items of myocardial enzyme spectrum and cTnT in normal control group was significantly lower than that in bafilomycin group (with t values from 2.39 to 10. 70, P values below 0.01). Conclusions: The activity of V-ATPase of myocardial lysosome decreased in rats after severe burn, which can result in myocardial damage by inhibiting myocardial autophagy flux.


Assuntos
Adenosina Trifosfatases , Queimaduras/metabolismo , Lisossomos , Miocárdio/metabolismo , Animais , Western Blotting , Queimaduras/patologia , Coração , Miocárdio/patologia , Ratos , Ratos Sprague-Dawley , Lesões dos Tecidos Moles , Índices de Gravidade do Trauma
4.
Genet Mol Res ; 14(3): 11495-504, 2015 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-26436390

RESUMO

This study aimed to investigate whether the differential expression of muscle development-related genes is one of the reasons why muscle development differs between Pekin, Jianchang, and Heiwu ducks, which are all domesticated duck breeds (Anas platyrhynchos domestica) breeds. At 2 weeks of age, the RNA expression of paired box 7 (Pax7), paired box 3 (Pax3), myogenic differentiation antigen (MYOD), and myogenin (MYOG) genes were measured by quantitative polymerase chain reaction, and Pax3 and Pax7 protein levels were detected by western blot assay. Myofiber morphology was investigated using paraffin-embedded muscle sections. At 8 weeks of age, 30 ducks of each breed were slaughtered for meat quality determination. The results revealed that Pax3 and Pax7 expression levels at both the RNA and protein levels were high in the Pekin duck. In addition, MYOG expression levels in the Jianchang duck were significantly higher than in the other two duck breeds (P < 0.05). There were no significant differences in MYOD expression levels between the breeds (P > 0.05). Myofiber diameter and cross-sectional area were the largest in the Pekin duck and the smallest in the Heiwu duck. There were significant differences in slaughter data between these breeds, and muscle content was greatest in the Pekin duck. The results indicate that the muscle content of three different duck breeds is associated with the expression of satellite-cell marker genes.


Assuntos
Patos/genética , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/metabolismo , Fatores de Transcrição Box Pareados/genética , Matadouros , Animais , Western Blotting , Cruzamento , Extremidades , Regulação da Expressão Gênica , Proteína MyoD/genética , Proteína MyoD/metabolismo , Miogenina/genética , Miogenina/metabolismo , Tamanho do Órgão/genética , Fatores de Transcrição Box Pareados/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
5.
Transplant Proc ; 43(10): 3604-12, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22172813

RESUMO

OBJECTIVE: n-3 polyunsaturated fatty acid (n-3 PUFA) are considered to be associated with liver regeneration. We investigated the effects of n-3 PUFA on hepatic tight junction (TJs) and liver regeneration after 70% partial hepatectomy (PH) in rats. METHODS: Male Sprague-Dawley rats were divided into four groups: sham group; control group, fish oil (FO; 1 mL/kg), and the FO (2 mL/kg) group. We examined changes in expression of hepatic TJs by at confocal microscopy in liver regeneration by routine clinical chemistry methods for hepatic function, and in activation of liver kinase B1-adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. Using Western blot analysis. RESULTS: After PH survival was higher in the FO than the control group. We observed treatment with n-3 PUFA to activated the LKB1-AMPK signaling pathway as well as to earlier, stronger and prolonged of the expression of Occludin, Claudin-3, zonula occludens-1, and proliferating cell nuclear antigen proteins. In addition, hepatic TJ structures and the level of liver function were protected after n-3 PUFA treatment. CONCLUSIONS: After PH in rats, n-3 PUFA enhanced expression and protected the structure of hepatic TJs via the LKB1-AMPK signaling pathway. Moreover, it may promote liver regeneration partly via the LKB1-AMPK signaling pathway. It protected postoperative hepatic function and may be a liver protective agent against liver failure.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Ácidos Graxos Ômega-3/farmacologia , Hepatectomia , Regeneração Hepática/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/cirurgia , Proteínas Serina-Treonina Quinases/metabolismo , Quinases Proteína-Quinases Ativadas por AMP , Animais , Western Blotting , Proliferação de Células/efeitos dos fármacos , Claudina-3 , Claudinas/metabolismo , Ativação Enzimática , Fígado/enzimologia , Fígado/patologia , Masculino , Proteínas de Membrana/metabolismo , Microscopia Confocal , Ocludina , Fosfoproteínas/metabolismo , Fosforilação , Antígeno Nuclear de Célula em Proliferação/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/enzimologia , Fatores de Tempo , Proteína da Zônula de Oclusão-1
6.
Phytomedicine ; 17(2): 100-7, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20060276

RESUMO

Gegen Qinlian dispensing granule, a favorite composite formula, is a combination of Radix Puerariae Lobatae, Radix Scutellariae, Rhizoma Coptidis and Radix et Rhizoma Glycyrrhizae Praeparata cum Melle. To develop a method to overall evaluate correlation between the formula and its four raw herbs, LC fingerprints of the formula and its raw herbs were developed and LC-DAD-MS was employed to identify the components in the formula fingerprint. According to the characteristic fragmentation behavior of known flavonoids, alkaloids and saponins isolated from the four raw herbs as well as retention time, UV and MS data of detected compounds, a total of 23 constituents in the formula fingerprint were structurally characterized. Chemical correlation between the formula and the four crude herbs was evaluated qualitatively and quantitatively by the developed LC fingerprints. The results showed that 8 components in the formula fingerprint were addressed to Radix Puerariae Lobatae, 11 to Radix Scutellariae, 7 to Rhizoma Coptidis, 3 to Radix et Rhizoma Glycyrrhizae Praeparata cum Melle, and that the relative area ratios of the common peaks in the formula vary slightly in comparison with corresponding ratios in its crude herbs, demonstrating the chemical constituents in the formula have patterns similar to those in its crude herbs.


Assuntos
Medicamentos de Ervas Chinesas/química , Medicina Herbária , Plantas Medicinais/química , Cromatografia Líquida , Coptis/química , Glycyrrhiza/química , Fitoterapia , Raízes de Plantas , Pueraria/química , Controle de Qualidade , Rizoma , Scutellaria/química , Espectrometria de Massas por Ionização por Electrospray
7.
Fresenius J Anal Chem ; 370(8): 1052-60, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11583086

RESUMO

Over the past decade a few methods for determining kinetic data for atom formation from the absorption signal in electrothermal atomic absorption spectrometry (ETAAS) have been developed in the author's laboratory. These approaches include improvement to the Smets method, and development of new methods for simultaneous determination of kinetic order and activation energy for atom formation at increasing or constant temperatures. The steady-state approximation and first-order kinetic assumption for atom formation have been avoided during their derivation. One of the most distinct features of these new methods is their suitability for quantitative determination of the kinetic order for atom formation from absorption signals under normal analytical conditions, even for atomization processes with fractional reaction orders and/or with multiple mechanisms. The application of the developed methods to the study of the mechanism of atomization in the graphite-furnace atomizer, with and without chemical modifiers, is reviewed with emphasis on research work in the authors' laboratory.

8.
Guang Pu Xue Yu Guang Pu Fen Xi ; 21(5): 649-54, 2001 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-12945321

RESUMO

Recent advances of the atomization kinetics in electrothermal atomic absorption spectrometry are critically reviewed with 31 references during 1994-2000. These include new methods for the determination of kinetic parameters, a two-parameters, a two-precursor model for the kinetics of analyte atomization, a kinetic model of atomization with redeposition, and the influences of matrices, chemical modifiers and atomizer surfaces on analyte atomization in an electrothermal atomizer.


Assuntos
Modelos Teóricos , Espectrofotometria Atômica/métodos , Termodinâmica , Fenômenos Químicos , Físico-Química , Cinética , Nebulizadores e Vaporizadores
10.
Zhongguo Zhong Xi Yi Jie He Za Zhi ; 21(8): 573-5, 2001 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-12575567

RESUMO

OBJECTIVE: To observe the effect of Tongmai Yizhi capsule (TMYZC) on learning in patients of vascular dementia (VD). METHODS: Thirty patients of VD were treated by oral administration of TMYZC, the changes in them before and after treatment were observed and compared with those in the 20 patients treated with hydergine as control. RESULTS: The total effective rate in the TMYZC treated group was 70.67% while that in the control group was 70.00%, the difference between the two groups was insignificant. CONCLUSION: Both TMYZC and hydergine have the effects of dilating blood vessels, increasing the cerebral blood flow, lowering the hyper-coagulative status and improving the free radical scavenging capability of patients.


Assuntos
Circulação Cerebrovascular/efeitos dos fármacos , Demência Vascular/tratamento farmacológico , Medicamentos de Ervas Chinesas/uso terapêutico , Fitoterapia , Idoso , Cápsulas , Demência Vascular/sangue , Feminino , Sequestradores de Radicais Livres/uso terapêutico , Humanos , Masculino , Pessoa de Meia-Idade
11.
Anal Chem ; 72(8): 1879-84, 2000 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-10784157

RESUMO

A method has been developed for the speciation of trace dissolved Fe(II) and Fe(II) in water by on-line coupling of flow injection separation and preconcentration with inductively coupled plasma mass spectrometry (ICPMS). Selective determination of Fe(III) in the presence of Fe(II) was made possible by on-line formation and sorption of the Fe(III)-pyrrolidinecarbodithioate (PDC) complex in a PTFE knotted reactor over a sample acidity range of 0.07-0.4 mol L(-1) HCl, elution with 1 mol L(-1) HNO3, and detection by ICPMS. Over a sample acidity range of 0.001-0.004 mol L(-1) HCl, the sum of Fe(III) and Fe(II), i.e., Fe(III + II), could be determined without the need for preoxidation of Fe(II) to Fe(III). The concentration of Fe(II) was obtained as the difference between those of Fe(III + II) and Fe(III). With a sample flow rate of 5 mL min(-1) and a 30-s preconcentration time, an enhancement factor of 12, a retention efficiency of 80%, and a detection limit (3s) of 0.08 microg L(-1) were obtained at a sampling frequency of 21 samples h(-1). The relative standard deviation (n = 11) was 2.9% at the 10 microg L(-1) Fe(III) level. Recoveries of spiked Fe(III) and Fe(II) in local tap water, river water, and groundwater samples ranged from 95% to 103%. The concentrations of Fe(III) and Fe(II) in synthetic aqueous mixtures obtained by the proposed method were in good agreement with the spiked values. The result for total iron concentration in the river water reference material SLRS-3 was in good agreement with the certified value. The method was successfully applied to the determination of trace dissolved Fe(III) and Fe(II) in local tap water, river water, and groundwater samples.


Assuntos
Ferro/análise , Água Doce/química , Espectrometria de Massas , Oxirredução , Reprodutibilidade dos Testes , Solubilidade
12.
Anal Chem ; 71(19): 4216-22, 1999 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-10660437

RESUMO

A simple and highly selective flow injection on-line pre-concentration and separation-flame atomic absorption spectrometric method was developed for routine analysis of trace amounts of lead in biological and environmental samples. The selective preconcentration of lead was achieved in a wide range of sample acidity (0.075 to > or = 3 mol L(-1)HNO3) on a microcolumn (145 microL) packed with a macrocycle immobilized on silica gel. The lead retained on the column was effectively eluted with an EDTA solution (0.03 mol L(-1), pH 10.5). Three kinds of potential interferences, i.e., preconcentration inferences from metal ions with an ionic radius similar to that of Pb(II) due to their competition for the cavity of the macrocyle, elution kinetic interferences from ions which form stable complexes with EDTA due to their competition for EDTA, and interferences in the atomizer from residual matrix, were evaluated and compared in view of the read-out mode of the analyte response (peak area vs peak height), column wash step (with vs without), column capacity (50 vs 145 microL), and column shape (conical vs cylindrical). The results showed that a combination of increase in column capacity, quantitation based on peak area, and use of dilute nitric acid for column wash before elution efficiently avoid the above-mentioned potential interferences. With the use of a 145 microL column the present system tolerated up to 0.1 g L(-1) Ba(II), 1 g L(-1) Sr(II), and at least 10 g L(-1) Fe(III), Cu(II), Ni(II), Zn(II), Cd(II), Al(III), K(I), Na(I), CaII), and Mg(II) in the sample digest. Further improvement of the interference tolerance can be achieved by increasing column capacity if more complicated samples need to be analyzed. At a sample loading rate of 3.9 mL min(-1) with 30-s preconcentration, an enrichment factor of 52, a detection limit (3s) of 5 micrograms L(-1) Pb in the digest and a sampling frequency of 63 h(-1) were obtained. The precision (RSD, n = 11) at the 200 micrograms L(-1) level was 1.9%. The enrichment factor and the detection limit can be further improved by increasing sample loading rate without degradation in the efficiency due to the favorable kinetics and low hydrodynamic impedance of the present system. The analytical results obtained by the proposed method for a number of biological and environmental standard reference materials were in good agreement with the certified and recommended values.


Assuntos
Monitoramento Ambiental/métodos , Chumbo/análise , Espectrofotometria Atômica/métodos , Animais , Cobre/química , Ácido Edético/química , Concentração de Íons de Hidrogênio , Imunoadsorventes , Ferro/química , Chumbo/sangue , Chumbo/química , Nephropidae/química , Níquel/química , Sílica Gel , Dióxido de Silício , Solo/análise
13.
Anal Chem ; 71(19): 4353-60, 1999 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-10660440

RESUMO

A flow injection manifold with an air-segmented and air-transported operational sequence for on-line coupling of microcolumn separation and preconcentration to electro-thermal atomic absorption spectrometry (ETAAS) was developed for the determination of (ultra)trace selenite and selenate in water. The determination of selenite was achieved by selective reaction with pyrrolidine dithiocarbamate (PDC), sorption of the resultant Se-PDC compound onto a conical microcolumn (10.2 microL) packed with RP C18 sorbent, elution with ethanol, and detection by ETAAS. The concentration of selenate was obtained as the difference between the concentrations of selenite after and before prereduction of selenate to selenite. With the developed manifold and operation sequence,the dispersion during elution and eluate transport and the eluent volume required for complete elution of the sorbed analyte were minimized. As a result, the sorbed analyte was quantitatively eluted from the column with only 26 microL of ethanol, and all the eluate was automatically introduced into the graphite tube by an air flow without the need of preheating the graphite tube or precise timing. Pretreatment of the graphite tube with iridium as a long-term "permanent" modifier effectively prevented analyte loss arising from the high volatility of the Se-PDC compound and greatly improved the precision, sensitivity, and detection limit. One thermal pretreatment of the graphite tube with injection of 150 microgram of iridium made possible at least 200 repetitive atomization cycles. With a preconcentration time of 180 s and a sample flow rate of 1.4 mL min(-1), an enhancement factor of 112 was achieved in comparison with direct injection of 30 microL of aqueous solution. The detection limit (3s) was 4.5 ng L(-1)Se. The RSD (n = 7) was 3.8% at 20 ng L(-1)Se. The concentrations of selenite and selenate determined in synthetic aqueous mixtures were in good agreement with the expected values. The recoveries for selenite from spiked seawater samples ranged from 98 to 102%. The concentrations of selenite in several seawater reference materials obtained with simple aqueous standard solutions for calibration agreed well with the certified and information values, respectively. In addition, the developed method was successfully applied to the certification of selenite and selenate in water.


Assuntos
Água Doce/análise , Compostos de Selênio/análise , Selenito de Sódio/análise , Espectrofotometria Atômica/métodos , Oligoelementos/análise , Ácido Selênico
14.
Anal Chem ; 70(22): 4736-42, 1998 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-9844570

RESUMO

A method has been developed for determination of (ultra)trace amounts of As(III) and As(V) in water by flow injection on-line sorption preconcentration and separation coupled with inductively coupled plasma mass spectrometry (ICPMS) using a knotted reactor (KR). The determination of As(III) was achieved by selective formation of the As(III)-pyrrolidine dithiocarbamate complex over a sample acidity range of 0.01-0.7 mol L-1 HNO3, its adsorption onto the inner walls of the KR made from 150-cm-long, 0.5-mm-i.d. PTFE tubing, elution with 1 mol L-1 HNO3, and detection by ICPMS. Total inorganic arsenic was determined after prereduction of As(V) to As(III) in a 1% (m/v) L-cysteine-0.03 mol L-1 HNO3 media. The concentration of As(V) was calculated by difference (the total inorganic arsenic and As(III)). Owing to the group-specific character of the chelating agent, and the use of an efficient rinsing step before elution, the interferences encountered in conventional ICPMS from common major matrix, alkali and alkaline earth metals, and chlorides were eliminated. The presence of organoarsenic species such as monomethylarsonate and dimethylarsinate in water samples had no effect on the results of As(III) and As(V). Thus, the method can be applied to the speciation analysis of inorganic arsenic at submicrogram per liter levels in aqueous solutions with high total content of dissolved solid and/or high content of chlorides. Using a preconcentration time of 60 s and a sample flow rate of 5 mL min-1, an enhancement factor of 22 was achieved in comparison with conventional ICPMS. The time required for a single determination was 200 s. The detection limits (3s) was evaluated to be 0.021 microgram L-1 for As(III) and 0.029 microgram L-1 for total inorganic arsenic. The precision for 14 replicate determinations of 1 microgram L-1 As(III) was 2.8% (RSD) with drift correction and 3.9% (RSD) without drift correction. The concentrations of As(III) and As(V) in synthetic mixtures obtained by the present method were in good agreement with expected values. Results obtained by the proposed method for total arsenic in a river water reference material agreed well with certified and recently reevaluated values. The method was also applied to the speciation analysis of inorganic arsenic in porewaters.


Assuntos
Arsênio/análise , Abastecimento de Água/análise , Concentração de Íons de Hidrogênio , Indicadores e Reagentes , Espectrometria de Massas
15.
Talanta ; 40(12): 1839-46, 1993 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18965860

RESUMO

The kinetic parameters of indium atomization in electrothermal atomic absorption spectrometry (ETAAS) have been determined by a newly proposed method. Effect of the atomizer surface and the palladium modifier on the kinetics of indium atomization has been investigated. The mechanisms of indium atomization seem to be identical for the pyrolytically coated graphite and the uncoated graphite tubes, i.e. the rate-limiting step for the atomization changes from a first order kinetics at lower temperatures into a nearly 1/3 order kinetics at higher temperatures, which may suggest that the analyte moves from a dispersed state to agglomates with increasing temperature. However, for the zirconium coated graphite tube, the atomization of indium is controlled by a single mechanism with the kinetic order of near 2/3 and the activation energy of 186 +/- 13 kJ/mol. Relatively weak indium-zirconium carbide interactions and the release of indium from the sphere of molten indium metal on the zirconium coated surface are suggested. In the presence of palladium, a simple mechanism, i.e. the release of indium from the solid solution of the In and the Pd on the pyrolytically coated graphite surface, is proposed to account for the observed first order kinetics and the activation energy of 421 +/- 27 kJ/mol.

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