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Spectrophotometric determination of Bromate in water using multisyringe flow in...

Oliveira, Sara M.; Segundo, Marcela A.; Rangel, António O. S. S.; Lima, José L. F. C.; Cerdà, Víctor

A multisyringe flow injection system for the spectrophotometric determination of bromate in water is proposed, based on the oxidation of phenothiazine compounds by bromate in acidic medium. Several phenothiazines were tested, including chlorpromazine, trifluoperazine, and thioridazine. Higher sensitivity and lower LOD were attained for chlorpromazine. Interference from nitrite, hypochlorite, and chlorite was el...


Automatic flow system for sequential determination of ABTS scavenging capacity ...

Magalhães, Luís M.; Segundo, Marcela A.; Reis, Salette; Lima, José L.F.C.; Tóth, Ildikó V.; Rangel, António O.S.S.

In the present work, an automatic flow procedure for the sequential spectrophotometric determination of Folin-Ciocalteu reducing capacity (FC assay) and 2,2 -azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS•+) scavenging capacity expressed as the trolox equivalent (TEAC assay) is proposed for a comparative study of antioxidant properties in food products. Exploiting the flexibility of flow ...


Spectrophotometric determination of bromate in drinking water using a multi-syr...

Oliveira, Sara M.; Segundo, Marcela A.; Lima, José L. F. C.; Cerdà, Victor; Rangel, António O. S. S.


Spectrophotometric determination of bromate in drinking water using a multi-syr...

Oliveira, Sara M.; Segundo, Marcela A.; Lima, José L. F. C.; Cerdà, Victor; Rangel, António O. S. S.


Potentiometric multi-syringe flow injection system for determination of exchang...

Almeida, M. Inês G.S.; Segundo, Marcela A.; Lima, José L.F.C.; Rangel, António O.S.S.

A multi-syringe flow injection system for the potentiometric determination of exchangeable potassium in soil samples is proposed. Firstly, a manifold was devised to allow determination in soil extracts prepared off-line. It was possible to analyze samples prepared in extractants with different composition (Mehlich or Morgan) without physical or chemical modification of the manifold. A linear dynamic concentrati...


Multi-syringe flow injection system for the determination of available phosphor...

Almeida, M. Inês G. S.; Segundo, Marcela A.; Lima, José L. F. C.; Rangel, António O. S. S.

Considering the importance of monitoring the levels of nutrients present in soils and their availability to plants, an automatic methodology is proposed based on multi-syringe flow injection analysis (MSFIA) for the spectrophotometric determination of available phosphorus in soil extracts. This fully computerized flow technique allowed the development of a flow network where sample and reagents were intercalate...


Avaliação comparativa da utilização de compostos da família das fenotiazinas pa...

Oliveira, Sara M.; Segundo, Marcela A.; Lima, José L. F. C.; Cerdà, Victor; Rangel, António O. S. S.


Avaliação comparativa da utilização de compostos da família das fenotiazinas pa...

Oliveira, Sara M.; Segundo, Marcela A.; Lima, José L. F. C.; Cerdà, Victor; Rangel, António O. S. S.


Sample introduction in multi-syringe flow injection systems: comparison between...

Segundo, Marcela A.; Oliveira, Hugo M.; Lima, José L. F. C.; Almeida, M. Inês G. S.; Rangel, António O. S. S.

In multi-syringe flowinjection analysis (MSFIA), devices as selection, injection or commutation valves must be incorporated to the manifold to provide access to sample and standard solutions. Therefore, the definition of sample amount can be either volume or time-based. In the present work, four configurations for sample introduction (two for each approach) were tested in order to establish if the different str...


Automatic flow systems based on sequential injection analysis for routine deter...

Segundo, Marcela A.; Lima, José L.F.C.; Rangel, António O.S.S.

Sequential injection systems for wine analysis have been developed in recent years for determination of more than 20 species. Several aspects of these systems are reviewed in the present paper. Special focus is given to implementation of in-line sample treatment and adaptation of system operation through software control to enable determination in different types of wine. The strategies used to enhance selectiv...


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Fundação para a Ciência e a Tecnologia Universidade do Minho   Governo Português Ministério da Educação e Ciência Programa Operacional da Sociedade do Conhecimento União Europeia