Multicommutation in flow analysis. Part 6. Binary sampling for wide concentration range turbidimetric determination of sulphate in plant digests

Vieira, Joana; Reis, Boaventura F.; Kronka, Eloisa A.M.; Paim, Ana Paula S.; Giné, María Fernanda

doi:10.1016/s0003-2670(98)00112-3

Cited by 17 publications

(6 citation statements)

References 8 publications

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“…Successive injections of different aliquots taken from a dispersing sample can be also performed [41]. This zone sampling approach has been used mainly to widen the concentration range of an analytical procedure [42].…”

Section: Sample Insertionmentioning

confidence: 99%

Multi-commutation in flow analysis: Recent developments and applications

Feres¹,

Fortes²,

Zagatto³

et al. 2008

Analytica Chimica Acta

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Section: Sample Insertionmentioning

confidence: 99%

Multi-commutation in flow analysis: Recent developments and applications

Feres¹,

Fortes²,

Zagatto³

et al. 2008

Analytica Chimica Acta

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“…This was also the first turbidimetric FIA system reported, only a few years after the FIA concept been introduced, which indicates the easy implementation of this reaction to flow systems. Since then, several researchers have developed not only other FIA systems, [13 -30,35,36,39] but also SIA, [31,32,34,35,37,38] MCFIA, [33] and MSFA [35] methodologies in order to obtain better precision and sensitivity, shorter analytical cycles, and lower detection limits. Alternatively, a FI procedure based on PbSO 4 colloidal formation in ethanol -water was proposed by Santelli el al.…”

Section: Sulfatementioning

confidence: 99%

“…[11,12,40] For this purpose and for both reactions, different surfactants were used, namely poly(vinyl alcohol) (PVA), [12,13,15,19,21,26,28,36 -39] gelatine, [14,16 -18,20,31,32,34] thymol, [16 -18,31,32,34] arabic gum, [22,23,25,27] and Tween 80. [33,35] The nucleation of barium sulfate is strongly pH dependent. [11] The pH not only affects the formation or dissolution of the barium sulfate precipitate but also its structure.…”

Section: Sulfatementioning

confidence: 99%

Turbidimetric and Nephelometric Flow Analysis: Concepts and Applications

Morais

Tóth

Rangel

2006

Spectroscopy Letters

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A review on flow analysis with turbidimetric and nephelometric detection is presented. A brief discussion of the principles of turbidimetry and nephelometry is given. Particular emphasis is devoted to coupling different flow techniques (flow injection, sequential injection, multicommutation) to these detection techniques. Applications in environmental, pharmaceutical, biological, and food samples are summarized and compared in terms of application range, flow configuration, repeatability, and sampling rate.

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“…There are various methods available for the determination of sulfate (Crompton, 1996). Examples include a titrimetric (Masadome and Asano, 1999), gravimetric (Prada et al, 1996;Vieira et al, 1998;Staden and Taljaard, 1996), colorimetric (Nakamura et al, 1997), spectrophotometric (Molinero et al, 1996), Raman and IR methods (Lijour et al, 1994;Murata et al, 1997), as well as ion chromatography (Micheel et al, 1998;Miura et al, 1997), and ion selective electrode-based methods (Li et al, 1999). Some of these methods are cumbersome, time-consuming, and lack selectivity.…”

Section: Introductionmentioning

confidence: 99%

Rationally designed fluorescently labeled sulfate‐binding protein mutants: Evaluation in the development of a sensing system for sulfate

Shrestha

Salins

Ensor

et al. 2002

Biotech & Bioengineering

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Periplasmic binding proteins from E. coli undergo large conformational changes upon binding their respective ligands. By attaching a fluorescent probe at rationally selected unique sites on the protein, these conformational changes in the protein can be monitored by measuring the changes in fluorescence intensity of the probe which allow the development of reagentless sensing systems for their corresponding ligands. In this work, we evaluated several sites on bacterial periplasmic sulfate-binding protein (SBP) for attachment of a fluorescent probe and rationally designed a reagentless sensing system for sulfate. Eight different mutants of SBP were prepared by employing the polymerase chain reaction (PCR) to introduce a unique cysteine residue at a specific location on the protein. The sites Gly55, Ser90, Ser129, Ala140, Leu145, Ser171, Val181, and Gly186 were chosen for mutagenesis by studying the three-dimensional X-ray crystal structure of SBP. An environment-sensitive fluorescent probe (MDCC) was then attached site-specifically to the protein through the sulfhydryl group of the unique cysteine residue introduced. Each fluorescent probe-conjugated SBP mutant was characterized in terms of its fluorescence properties and Ser171 was determined to be the best site for the attachment of the fluorescent probe that would allow for the development of a reagentless sensing system for sulfate. Three different environment-sensitive fluorescent probes (1,5-IAEDANS, MDCC, and acylodan) were studied with the SBP171 mutant protein. A calibration curve for sulfate was constructed using the labeled protein and relating the change in the fluorescence intensity with the amount of sulfate present in the sample. The detection limit for sulfate was found to be in the submicromolar range using this system. The selectivity of the sensing system was demonstrated by evaluating its response to other anions. A fast and selective sensing system with detection limits for sulfate in the submicromolar range was developed.

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Multicommutation in flow analysis. Part 6. Binary sampling for wide concentration range turbidimetric determination of sulphate in plant digests

Cited by 17 publications

References 8 publications

Multi-commutation in flow analysis: Recent developments and applications

Multi-commutation in flow analysis: Recent developments and applications

Turbidimetric and Nephelometric Flow Analysis: Concepts and Applications

Rationally designed fluorescently labeled sulfate‐binding protein mutants: Evaluation in the development of a sensing system for sulfate

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