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1.
Animal ; 16(7): 100564, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35738085

RESUMO

The transfer of hatchability results obtained under experimental conditions to the commercial ground with a positive financial effect proves the value and usefulness of these data. On the other hand, finding results on commercial processes of broiler breeders' egg incubation in the literature is challenging. The presented study aimed to determine the effects of egg weight and storage time on the physical, biochemical characteristics of hatching eggs, embryogenesis and hatchability in Ross 308 broiler breeders. On the laying day, the eggs were divided into four weight groups: S - small eggs (57-61 g), M - medium eggs (62-66 g), L - large eggs (67-71 g), and XL - extra-large eggs (72-76 g). The eggs were then stored for 3, 7, 14, and 21 days under controlled conditions. As the egg storage time increased, a decrease in the yolk quality (lower index) was observed. The highest Haugh units were found in eggs from the S and M groups. The cholesterol content of the M, L, and XL groups was lower on days 7, 14, and 21 as compared to that of eggs only stored for 3 days. Egg weight loss during incubation decreased with an increase in the egg weight. An extension of the egg storage time caused an increase in the loss of egg weight. On the 14th and 18th days of hatching, an increase in the eggshell temperature was noted with an increase in the weight of the egg. The eggs stored for 7 days were characterised by the highest shell temperature on each day. The highest hatchability percentage was recorded for the M group. The hatchability rate decreased with the prolongation of the storage time, while the number of crippled chicks after hatching increased. The results confirmed that the increased weight of the eggs and prolonged storage time (14 and 21 days) increased the weight and decreased the length of the newly hatched chicks, respectively. Chicks from the heaviest eggs and those stored for 14 and 21 days showed poor results on the Pasgar score® test. The observations indicate the need to adopt various (of those available) methods to assess the quality of newly hatched chicks in hatcheries in order to produce high-quality broiler chickens. The results also indicate that prolonged egg storing beyond 14 days may affect the thyroid hormone economy during the hatching of chicks, especially in the XL group.


Assuntos
Galinhas , Óvulo , Animais , Casca de Ovo , Desenvolvimento Embrionário , Hormônios Tireóideos
2.
J Chem Phys ; 128(17): 174704, 2008 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-18465933

RESUMO

The adsorption and electron irradiation of methyl methacrylate (MMA) on a Ru(1010) surface have been studied using x-ray photoelectron spectroscopy (XPS), temperature programmed desorption (TPD), and low energy ion scattering. TPD analysis indicates that a monolayer of MMA chemisorbs and dissociates on the Ru(1010) surface. The reaction products observed upon heating include H(2), CO, CO(2), and a small amount of MMA. Physisorbed multilayers of MMA desorb at temperatures around 170 K. Electron irradiation of physisorbed MMA at 140 K leads to a modification of the MMA film: The XPS spectra show an increase in thermal stability of the film with retention of the MMA structure, and indicate that electron irradiation induces polymerization. An increase in the electron bombardment fluence induces a degradation of the formed polymerized species and leads to the accumulation of carbon on the Ru surface. These results are relevant to the accumulation of carbon on surfaces of Ru films that serve as capping layers on MoSi multilayer mirrors used in extreme ultraviolet lithography.

3.
J Mol Recognit ; 20(6): 524-30, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18004715

RESUMO

Changes in the stiffness of hog pericardium tissue, native and treated with dimethyl suberimidate (DMS), are investigated by atomic force microscopy (AFM). Young's modulus is calculated on the basis of the Hertz-Sneddon model. The cross-linking process increases the stiffness of the tissue. The values of Young's modulus are higher for the DMS stabilized pericardium than for the native one. We also observe that the Young's modulus of native tissue increases when the time between getting the biological material and performing the measurements is longer. This process is probably connected with natural degradation of the biological samples.


Assuntos
Dimetil Suberimidato/farmacologia , Microscopia de Força Atômica , Pericárdio/efeitos dos fármacos , Pericárdio/ultraestrutura , Animais , Fenômenos Biomecânicos , Reagentes de Ligações Cruzadas/farmacologia , Processamento de Imagem Assistida por Computador , Pericárdio/química , Propriedades de Superfície , Suínos , Fatores de Tempo , Preservação de Tecido/métodos
4.
Planta ; 224(6): 1363-72, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16773376

RESUMO

Huge advances achieved recently in elucidating the role of NO in plants have been made possible by the application of NO donors. However, the application of NO to plants in various forms and doses should be subjected to detailed verification criteria. Not all metabolic responses induced by NO donors are reliable and reproducible in other experimental designs. The aim of the presented studies was to investigate the half-life of the most frequently applied donors (SNP, SNAP and GSNO), the rate of NO release under the influence of light and reducing agents. At a comparable donor concentration (500 microM) and under light conditions the highest rate of NO generation was found for SNAP, followed by GSNO and SNP. The measured half-life of the donor in the solution was 3 h for SNAP, 7 h for GSNO and 12 h for SNP. A temporary lack of light inhibited NO release from SNP, both in the solution and SNP-treated leaf tissue, which was measured by the electrochemical method. Also a NO, selective fluorescence indicator DAF-2DA in leaves supplied with different donors showed green fluorescence spots in the epidermal cells mainly in the light. SNP as a NO donor was the most photosensitive. The activity of PAL, which plays an important role in plant defence, was also activated by SNP in the light, not in the dark. S-nitrosothiols (SNAP and GSNO) also underwent photodegradation, although to a lesser degree than SNP. Additionally, NO generation capacity from S-nitrosothiols was shown in the presence of reducing agents, i.e. ascorbic acid and GSH, and the absence of light. The authors of this paper would like to polemicize with the commonly cited statement that "donors are compounds that spontaneously break down to release NO" and wish to point out the fact that the process of donor decomposition depends on the numerous external factors. It may be additionally stimulated or inhibited by live plant tissue, thus it is necessary to take into consideration these aspects and monitor the amount of NO released by the donor.


Assuntos
Doadores de Óxido Nítrico/farmacologia , Óxido Nítrico/metabolismo , Fenilalanina Amônia-Liase/metabolismo , Plantas/efeitos dos fármacos , Luz , Microscopia Confocal , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Plantas/enzimologia , Plantas/metabolismo
5.
Ultramicroscopy ; 95(1-4): 165-9, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12535561

RESUMO

Thermally cleaned W(211) surface with 0.7 degrees miscut consists of (211) terraces separated by monoatomic steps. When the surface is exposed to oxygen and subsequently annealed at 1100-1900 K, the width of (211) terraces increases and multilayer steps are formed. Similar step bunching is observed during routine cleaning of the sample by annealing in oxygen and thermal flashing in ultra high vacuum. During such cleaning procedure islands of c(6 x 4) reconstruction are observed.

6.
Anal Chem ; 72(14): 3203-9, 2000 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-10939388

RESUMO

The oxidation of 1,4-bis(3,4-dihydroxyphenyl)-2,3-dimethylbutane, known also as nordihydroguaiaretic acid, on a glassy carbon electrode anodically pretreated in KCl solution gives rise to a stabile redox-active polymer containing the o-quinone moiety. The redox response of the modified electrode is typical for a surface-immobilized species. The modifier thickness can be easy controlled by a number of potential cycles applied during electropolymerization, and a surface coverage up to 1.1 x 10(-9) mol cm(-2) can be achieved. The film exhibits catalytic activity toward NADH oxidation. Characteristic kinetic constants for the mediated oxidation of NADH were derived from rotating disk experiments performed in phosphate or Tris/acetate buffers. The effects of film thickness, solution pH, and the presence of Mg2+ cation on the catalytic efficiency of the modified electrode were discussed and compared with literature data concerning related systems.


Assuntos
Antioxidantes/química , Masoprocol/química , NAD/química , Catálise , Eletroquímica , Membranas Artificiais , Oxirredução , Polímeros
7.
Chir Narzadow Ruchu Ortop Pol ; 64(3): 273-8, 1999.
Artigo em Polonês | MEDLINE | ID: mdl-10495550

RESUMO

Early clinical and radiological results of Charnley hip arthroplasties performed in 1995-1998 in Department of Orthopaedics and Traumatology of Zeromski's City Hospital in Cracow are presented. Control evaluation was made in 86 hips (76 patients) among 155 hips (170 patients) which were done in this Department. 97 per cent good results in clinical and 100 per cent good results in radiological evaluation were found in controlled group. In group of 170 alloplasties were 4.1 per cent local and none system complications. Results in this series confirm Charnley prosthesis as a most effective device in treatment of many hip pathologies.


Assuntos
Artroplastia de Quadril/métodos , Procedimentos Cirúrgicos Operatórios/métodos , Idoso , Idoso de 80 Anos ou mais , Feminino , Hospitais Urbanos , Humanos , Masculino , Pessoa de Meia-Idade , Ortopedia , Polônia , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
8.
Anal Chem ; 71(5): 1055-61, 1999 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-21662775

RESUMO

A platinum electrode was modified with electropolymerized films of 4-allyl-2-methoxyphenol (eugenol) by its oxidative polymerization from an alkaline solution by cyclic voltammetry. The modified electrode was than used to determine dopamine (DA) in an excess of ascorbic acid (AA) by differential pulse voltammetry. The peak positions as well as relative sensitivity DA/AA were affected by the potential window applied for the polymerization. For polymerization between 0 and 2.2 V, the peak potentials recorded in a phosphate buffer solution (pH 7.4) were -61 and +152 mV vs Ag/AgCl for AA and DA, respectively. After a 5-min equilibration, relative sensitivity DA/AA was 164 and the current sensitivity for DA was 7.9 nA µM(-)(1). The detection limit for S/N = 3 is 0.1 µM. The high selectivity and sensitivity for DA was found to be due to charge discrimination/analyte accumulation and an effect of catalytic mediation of redox sites. Chronocoulometric data reveal that DA is accumulated on the electrode as a monolayer. The electrode is stable, reversible, and free of fouling problems.

9.
Pol Arch Med Wewn ; 96(1): 45-53, 1996 Jul.
Artigo em Polonês | MEDLINE | ID: mdl-8966145

RESUMO

The role of percutaneous transluminal coronary angioplasty (PTCA) in the management of chronically occluded coronary arteries is still controversial. Percutaneous transluminal coronary angioplasty of chronic total occlusion is associated with relatively low success rates and a high incidence of restenosis. The purpose of this analysis was to determine, from the records of our institution, the efficacy and long-term outcome of angioplasty performed for chronic total occlusion defined as complete occlusion (Thrombolysis in Myocardial Infraction [TIMI] grade 0). PTCA was performed in 212 consecutive patients with chronically occluded coronary arteries and was successful in 125 (59%) patients. Complications were not observed. Successful initial PTCA was related to the clinical duration of occlusion and the type of guidewire (the primary success rate with the conventional guidewire was 49 (48%) versus 76 (69.1%) with Magnum Meier System p < 0.01). Repeat angiography was performed for 65 (52.0%) consecutive patients with successful initial PTCA and demonstrated restenosis in 34 (52.3%). 17 patients were successfully treated by a second PTCA. Restenosis or reocclusion was not clearly related to the residual stenosis post PTCA. In addition, the grade of collateral supply was not different in the vessels with and without restenosis.


Assuntos
Trombose Coronária/terapia , Adulto , Angioplastia Coronária com Balão , Angiografia Coronária , Trombose Coronária/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva , Resultado do Tratamento , Grau de Desobstrução Vascular
10.
Eur Heart J ; 15(8): 1106-12, 1994 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-7988603

RESUMO

The effect of PTCA on global and regional left ventricular systolic function, isovolumic relaxation, chamber and muscle stiffness were studied in 30 patients with angina pectoris, previous non-Q wave anterior myocardial infarction (AMI) and significant stenosis of the left anterior descending coronary artery (LAD). In 11 of the 30 patients the condition was stable, but it was unstable in 19. Left ventricular angiograms were obtained before and 4.85 +/- 3.67 months after PTCA. The RAO was in the 30 degree projection, with the silhouette of the left ventricle sliced into 90 regions; changes in left ventricular volume, pressure and anterior wall thickness during the full cardiac cycle, together with dp/dt were demonstrated. After PTCA, global ejection fraction increased from 68.77 +/- 5.96% to 76.57 +/- 3.18%, P < 0.001. Impaired contractility was found in 29/90 (32.2%) regions before PTCA and in 5/90 (5.6%) after PTCA, P < 0.001. The time constant of the isovolumic pressure fall decreased after PTCA (52.56 +/- 17.40 ms vs 39.61 +/- 11.26 ms, P < 0.01). Elastic chamber stiffness coefficient decreased (0.022 +/- 0.003 vs 0.008 +/- 0.004, P < 0.001) and peak rate of left ventricular filling increased (319.0 +/- 107.9 ml.min-1 vs 396.8 +/- 201.4 ml.min-1, P < 0.05) after PTCA. The muscle stiffness coefficient was within normal values before and did not change after PTCA. The study findings show that in patients with persistent angina pectoris after non-Q wave AMI, complex systolic and diastolic ischaemic dysfunction occurs. This dysfunction can be reversed after successful PTCA of LAD.


Assuntos
Angioplastia Coronária com Balão , Diástole/fisiologia , Infarto do Miocárdio/terapia , Isquemia Miocárdica/terapia , Sístole/fisiologia , Disfunção Ventricular Esquerda/terapia , Adulto , Angina Pectoris/fisiopatologia , Angina Pectoris/terapia , Eletrocardiografia , Feminino , Seguimentos , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Contração Miocárdica/fisiologia , Infarto do Miocárdio/fisiopatologia , Isquemia Miocárdica/fisiopatologia , Estudos Prospectivos , Volume Sistólico/fisiologia , Disfunção Ventricular Esquerda/fisiopatologia , Função Ventricular Esquerda/fisiologia
11.
Pediatr Cardiol ; 15(3): 121-6, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-8047493

RESUMO

The clinical profile of 19 patients with dilated cardiomyopathy ages 2-18 years (mean 13.4 +/- 4 years) was reviewed to detect any factors that might be predictive for their survival. Follow-up range from 5 to 105 months (mean 39 +/- 33 months). Routine treatment consisted of digitalis and diuretics: 14 patients received antiarrhythmics, 6 received vasodilators, and 12 were managed with immunosuppression. There were 12 survivors and 7 nonsurvivors: The 1-year mortality was 21.2% and the 2-year mortality 35.8%. All deaths were within first 2 years. Of the 12 patients who survived 2 years, a significant improvement was noticed in 9. In 3 patients tachycardia-induced cardiomyopathy was diagnosed, and abolition of supraventricular tachycardia was followed by improvement and regression of cardiomegaly. Endomyocardial biopsy was performed in 16 patients. Four with a histologic diagnosis of active myocarditis survived, and in 3 of them a considerable improvement was noticed. Of the 12 patients with nonspecific histologic findings, 6 died (p < 0.05). There were no significant differences between survivors and nonsurvivors for any of the following parameters: incidence of severe heart failure (NYHA class III-IV) and severe ventricular arrhythmias (Lown class III-V), relative heart volume, echocardiographic left ventricular diastolic diameter and shortening fraction, and the hemodynamic parameters of cardiac index, left ventricular ejection fraction, left ventricular end-diastolic pressure, and left ventricular end-diastolic volume index.


Assuntos
Cardiomiopatia Dilatada/tratamento farmacológico , Cardiomiopatia Dilatada/fisiopatologia , Adolescente , Antiarrítmicos/uso terapêutico , Biópsia , Cardiomiopatia Dilatada/mortalidade , Criança , Ecocardiografia , Eletrocardiografia , Feminino , Seguimentos , Humanos , Imunossupressores/uso terapêutico , Masculino , Miocárdio/patologia , Prognóstico
12.
Kardiol Pol ; 35(12): 354-9, 1991.
Artigo em Polonês | MEDLINE | ID: mdl-1800830

RESUMO

UNLABELLED: The clinical profile of 19 patients with dilated cardiomyopathy from 2 to 18 years old (mean age 13.4 +/- 4 years) was reviewed to detect any factors that might be predictive for their survival. Follow-up study ranged from 5 to 105 months (mean 39 +/- 33 months). All patients received digitalis + diuretics, 12 were managed with immunosuppression, 16 with antiarrhythmics. There were 12 survivors and 7 nonsurvivors: the 1-year mortality was 21.2%, the 2-years mortality was 35.8%. All deaths were within first 2 years. In 12 patients who survived 2 years, significant improvement was noticed in 9 cases. Endomyocardial biopsy was performed in 16 patients. Four of them with histological diagnosis of myocarditis survived and in 3 of them a considerable improvement was noticed. Half of 12 patients with nonspecific histological findings died (p less than 0.05). There was no significant difference between survivors and nonsurvivors in all following parameters: the incidence of severe heart failure (NYHA class III-IV) and severe ventricular arrhythmias (Lown III-IV), relative heart volume, echocardiographic LVDD, haemodynamic parameters--CI, LVEF, LVEDP, LVEDVI. CONCLUSIONS: Clinical, electrocardiographic, echocardiographic and haemodynamic data are nonpredictive for survival. The most dangerous period are the first two years of illness. In long term, improvement was noticed in half of patients.


Assuntos
Cardiomiopatia Dilatada/diagnóstico , Adolescente , Amiodarona/uso terapêutico , Cardiomiopatia Dilatada/tratamento farmacológico , Cardiomiopatia Dilatada/mortalidade , Cardiomiopatia Dilatada/fisiopatologia , Criança , Pré-Escolar , Digoxina/uso terapêutico , Ecocardiografia , Eletrocardiografia , Feminino , Hemodinâmica/efeitos dos fármacos , Hemodinâmica/fisiologia , Humanos , Imunossupressores/uso terapêutico , Masculino , Prognóstico , Fatores de Tempo
13.
Talanta ; 37(10): 995-9, 1990 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18965054

RESUMO

The simultaneous determination of thallic and thallous ions, without preliminary separation, has been achieved by differential pulse anodic stripping voltammetry at a hanging mercury drop electrode. The electrochemical activity of thallic ions in 0.2M EDTA at pH 4.5 +/- 0.2 is inhibited by the addition of 0.01% poly(ethyleneglycol) of M.W. 20,000 (PEG 20,000). When the electrolyte also contains ascorbic acid at 0.01M concentration, the sum of thallic and thallous species can be determined.

14.
Pol Arch Med Wewn ; 81(2): 70-9, 1989 Feb.
Artigo em Polonês | MEDLINE | ID: mdl-2616359

RESUMO

Cardiac abnormalities were studied using the clinical, electrocardiographic and echocardiographic methods in 66 patients with systemic scleroderma. Abnormal ecg was seen in 41 patients (62.1%), most frequently in form ventricular extrasystole (21.2%), incomplete block of the right bundle branch (12.1%), left ventricular and right atrial hypertrophy (10.6%) each, and the pattern suggesting the history of past myocardial infarction (7.6%). Abnormal echocardiographic results were found in 38 patients (57.6%). The most usual changes, differentiating that group from the controls, were: sluggish diastolic movement of the posterior wall of the left ventricle (40.7%), pericardial effusion (37.0%), elongation of the isovolumic relaxation time diastole phase (99.3 s.m.v. 81.1 ms, p less than 0.001) and right ventricular dilatation. There were no significant differences between the scleroderma and the control group as regards the indices of the contractility of the left ventricle: ejection fraction (EF), velocity of circumferential fibres shortening (VCF), diastolic size of the left ventricle and of the left atrium. The prevalence of the electrocardiographic and echocardiographic abnormalities in particular types of scleroderma (diffuse, acroscleroderma, severe acroscleroderma, CREST) was roughly similar: 50-76%. Finding of the impaired diastolic rather than systolic function of the left ventricle and of the similar prevalence of the cardiac abnormalities in the particular types of scleroderma is new and contradictory to the commonplace opinions.


Assuntos
Cardiopatias/diagnóstico , Escleroderma Sistêmico/complicações , Adulto , Idoso , Ecocardiografia , Eletrocardiografia , Feminino , Cardiopatias/etiologia , Cardiopatias/fisiopatologia , Hemodinâmica/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Contração Miocárdica/fisiologia , Escleroderma Sistêmico/fisiopatologia
16.
Talanta ; 35(4): 329-31, 1988 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18964524

RESUMO

Conditions have been found which make possible the determination of copper in the presence of a large excess of bismuth by differential-pulse and anodic-stripping voltammetry without preliminary separation. The electrochemical activity of the bismuth, which usually interferes in the determination of copper, is inhibited by using tetrabutylammonium chloride (TBAC) as surfactant. In 0.2M EDTA and 0.01M ascorbic acid at pH 4.5 as supporting electrolyte without the surfactant present, trace levels of copper (1.5 x 10(-8)M) can be determined accurately if the molar ratio of bismuth to copper is not higher than 3, but if the electrolyte also contains TBAC at 0.01M concentration, bismuth can be tolerated in concentrations up to 10(-4)M, and the height of the copper peak is unaffected.

17.
Talanta ; 35(3): 191-7, 1988 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18964494

RESUMO

The possibilities for eliminating the matrix effect caused by large concentrations of titanium in an EDTA-based electrolyte have been examined. In these solutions titanium gives a DPASV peak, the height of which decreases with increase in preconcentration time. This effect depends on the pH and is probably caused by impurities in the EDTA. Complete damping of the titanium peak by means of this effect is not possible. The influence of the following surfactants on the DPASV peak for titanium in 0.2M EDTA at pH 4.5 was investigated: polyoxyethylated alkylphenols having an average of 3 and 9.5 ethylene oxide sub-units; polyoxyethylene alcohols having an average of 5 and 20 ethylene oxide sub-units; polyoxyethylene (glycerol mono-oleate) ether having an average of 20 ethylene oxide sub-units; polyoxyethylene (sorbitol mono-oleate) ether having an average of 20 ethylene oxide sub-units; poly(ethylene oxide) having M.W. 5.0 x 10(6); poly(ethylene oxide)poly(propylene oxide) block copolymer having M.W. 1.625 x 10(4); N,N,N,N',N',N'-hexamethylhexamethylenediammonium bromide (HMB); benzyl(diisobutylphenoxyethoxy) dimethylammonium chloride; hexadecyltrimethylammonium bromide; tetrabutylammonium chloride (TBAC); hexadecyldimethylbenzylammonium chloride, hexadecyltributylphosphonium bromide; tetraphenylphosphonium bromide; sodium dodecylsulphate; sodium stearate; sodium dodecylbenzenesulphonate; sodium octadecyloxyethylene ether sulphate; sodium octadecyloxyethylene ether malonate (Malester). Except for TBAC and HMB all the surfactants investigated decreased the titanium peak, although to different degrees. Generally the effect increased in the sequence cationic surfactants < non-ionic surfactants < anionic surfactants. The more hydrophobic non-ionic surfactants decreased the titanium peak more strongly than did the less hydrophobic ones. Malester was found the best of the investigated surfactants for this purpose. Sodium dodecylbenzenesulphonate also gave good results, although in this case an additional peak appeared. In the presence of these last two surfactants iron(III) does not substantially disturb the base-line current.

19.
Talanta ; 32(12): 1101-4, 1985 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18963962

RESUMO

The influence of the following surfactants on the peak of copper in 0.2M EDTA at pH 4.5 was investigated: polyoxyethylated alkylphenols having an average of 3 and 9.5 ethylene oxide units; polyoxyethylene alcohols having 4 and 7 ethylene oxide units; poly(ethylene glycols) having M.W. 4000, 9000 and 20000; hexadecyltributylphosphonium bromide (HDTBPB), tetraphenylphosphonium bromide (TPPB),N,N,N,N,N',N',N-examethylhexamethylenediammonium bromide (HMB), benzyl(di-isobutylphenoxyethoxy) dimethylammonium chloride (Hyamine 1622), hexadecyltrimethylammonium bromide (HDTMAB), hexadecyldimethylbenzylammonium chloride (HDDMBAC) and tetrabutylammonium chloride (TBAC). HDDMBAC, as well as all the substances examined which contained an ethylene oxide chain, completely suppressed the copper peak. HDTBPB and TPPB partially suppressed the peak, whereas HDTMAB, HMB and Hyamine 1622 enhanced it. TBAC was without effect. In 0.2M EDTA at pH 4.5 containing TBAC at 0.01M concentration and 10 ppm of Rokafenol N-3, Cu(II), Pb(II) and Bi(III) can be tolerated at concentrations of up to 0.05M, the height of the thallium peak being unaffected. The precision of the determination (3-10%) and the recovery are satisfactory. A 10(3)-fold ratio of Fe(III) to Tl(I) does not interfere with the determination.

20.
Talanta ; 32(11): 1051-4, 1985 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18963946

RESUMO

The determination of trace levels of thallium in bismuth and bismuth salts by differential pulse anodic-stripping voltammetry has been made possible by using a surfactant as an electrochemical masking agent, in addition to a complexing agent. In 0.2M EDTA at pH 4.5 as supporting electrolyte in the absence of surfactant, bismuth at concentrations below 10(-4)M does not interfere. When the electrolyte also contains tetrabutylammonium ions at 0.01 M concentration, bismuth can be tolerated at concentrations up 0.05M, and the height of the thallium peak is unaffected. It is thus possible to determine 1 nM Tl(I) in the presence of 0.05M Bi(III), i.e., Tl at the 1 x 10(-6)% level in bismuth. The precision of the determination and the recovery are satisfactory. Neither an 800-fold ratio of Cu(II) nor a 10(7)-fold ratio of Pb(II) to Tl(I) interferes in the determination. Other cations such as Zn(2+), Cd(2+), In(3+), Hg(2+), Fe(3+), Sb(3+) and Sn(4+) in 10(4)-fold molar ratio to Tl(I) have no effect on the determination. Thallium has been determined in bismuth metal and in bismuth nitrate of various degrees of purity.

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