Fluorimetric determination of fluoride in a flow assembly integrated on-line to an open/closed FIA system to remove interference by solid phase extraction

Garrido, Mariano; Lista, Adriana G.; Palomeque, Miriam E.; Band, Beatriz Susana Fernández

doi:10.1016/s0039-9140(02)00397-1

Cited by 38 publications

(13 citation statements)

References 9 publications

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“…The application of recirculating FIA systems has been demonstrated in the estimation of kinetics, (14) autocalibration, (15) and interference removal. (16) In this work, we developed a recirculating flow injection calorimetric biosensor with an improved structure consisting of a thermopile, a reaction cell, and a reference cell as well as an enhanced stability of immobilized chicken liver esterase. On the basis of a fast and easy test method, the calorimetric biosensor has been applied to the determination of dichlorvos using progress curve data.…”

Section: Introductionmentioning

confidence: 99%

A Recirculating Flow Injection Calorimetric Biosensor and Its Improved Performance Evaluation for Dichlorvos Detection

2018

Sensors and Materials

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A novel calorimetric biosensor is developed by recirculating flow injection analysis. The biosensor consists of a peristaltic pump, two switching valves, a thermostat, an injection valve, two twin cells (a reaction cell and a reference cell), a thermopile, a data acquisition module, and a personal computer (PC). This biosensor with an improved structure can respond to reaction heat timely by placing the thermopile between the reaction and reference cells. Enzymatic reaction will be continuous when an excessive substrate is introduced into the two cells and flows circularly through them. The calorimetric biosensor has been applied successfully in dichlorvos detection by a new test method. In this method, two parameters of constant response in the zero-order reaction phase and the transition moment from zero-order reaction to firstorder reaction are obtained from the progress curve of the enzymatic reaction. Under a certain initial enzyme activity derived from the transition moment, dichlorvos can be determined by comparing the difference in constant response caused by the enzymatic reaction with inhibition in the reaction cell and without inhibition in the reference cell. The performance shows a linear range of 0.01-0.5 mg/L with a relative standard deviation (RSD) of 3-10% and a limit of detection (LOD) of 0.01 mg/L, as well as a detection duration of 20 min. The system is fast, can repeatedly and easily be used, and can improve automation and prevent possible input errors. It is suitable for the rapid detection of pesticides in the field.

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Section: Introductionmentioning

confidence: 99%

A Recirculating Flow Injection Calorimetric Biosensor and Its Improved Performance Evaluation for Dichlorvos Detection

2018

Sensors and Materials

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“…6 Several other techniques have been reported for the determination of fluoride in drinking water, such as capillary electrophoresis, 7 solvent-extraction coupled to fluorometry. [8][9][10] There are a few spectrophotometric reports in the literature based on a decolorizing effect of fluoride on a colored metal-dye complex. 1,[11][12][13][14][15] Some of these mentioned techniques have special problems in determination of fluoride.…”

Section: Introductionmentioning

confidence: 99%

Spectrophotometric Determination of Trace Amounts of Fluoride Using an Al-Xylenol Orange Complex as a Colored Reagent

et al. 2009

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A new spectrophotometric reagent for the determination of trace amounts of fluoride has been introduced. This method is based on the decolorization of a complex of Al(III) with xylenol orange (XO) as an ultra-sensitive colored reagent. Since the Al-XO complex plays an important role in this method, the protonation and complexation of XO with Al(III) at an ionic strength of 0.1 mol L -1 at 25 C has been studied by a spectrophotometric global analysis method. The EQUISPEC program was used to evaluate the protonation constants of XO and the stability constants of the formed complexes with Al(III). The protonation and the stability constants of the major complex species such as ML, MLH and MLH2, were determined. Finally, a spectrophotometric method for the assay of fluoride based on a decrease of the color intensity of the Al-XO complex, in an aqueous solution has been designed. The effects of some important variables on the determination of fluoride based on the proposed method were investigated. The method was applied to the determination of fluoride under the optimum conditions (pH 5.2, ionic strength 0.1 mol L -1 , 25 C). The determination of fluoride in the range of 0.08 -1.4 μg mL -1 (SD = 1.2%) was successfully performed. Interferences of Fe(III) were easily eliminated by using ascorbic acid. The proposed method was applied to the determination of trace amounts of fluoride content of some real water samples.

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Section: Introductionmentioning

confidence: 99%

“…1,2 However, the World Health Organization (WHO) upper limit of fluoride in drinking water is 7.9 × 10 -5 mol dm -3 , and the high levels of fluoride have caused toxicity in animals and mottled teeth in humans. Several methods, such as ion-selective electrodes (ISE), 3 colorimetry, [4][5][6][7] fluorescence [8][9][10] and capillary electrophoresis, 11 have been reported for the determination of fluoride.Among these, the chemical systems that respond to the presence of ions by color change detectable by vision are rare. 12 These chemosensors do not have any need to use a potentiostat or a spectrometer to detect redox or optical perturbations, and as a result, have substantial advantages over other molecular chemosensors.…”

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Naked-Eye Detection of Fluoride Using Zr(IV)-EDTA Complex and Pyrocatechol Violet

Balaji

Matsunaga

2005

ANAL. SCI.

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The use of fluoride has been increasing because of its great potential for industrial and biological applications. 1,2 However, the World Health Organization (WHO) upper limit of fluoride in drinking water is 7.9 × 10 -5 mol dm -3 , and the high levels of fluoride have caused toxicity in animals and mottled teeth in humans. Several methods, such as ion-selective electrodes (ISE), 3 colorimetry, [4][5][6][7] fluorescence [8][9][10] and capillary electrophoresis, 11 have been reported for the determination of fluoride.Among these, the chemical systems that respond to the presence of ions by color change detectable by vision are rare. 12 These chemosensors do not have any need to use a potentiostat or a spectrometer to detect redox or optical perturbations, and as a result, have substantial advantages over other molecular chemosensors. 13 Lanthanum(III), Zr(IV) and Ce(III) complexes with dye compounds have been used for the colorimetric detection of fluoride.14 These systems have a lack of chemical stability, and take a long time for color development. Supramolecular compounds, such as trianthryl borane derivatives and calix(4)pyrrole derivatives have been examined as fluoride chemosensors via strong hydrogen-bond formation. 5,15 The observed color changes in these systems take place only in organic media, but are reversed upon the addition of water. As a result, procedures for the naked-eye detection of anions in aqueous media are needed to overcome the above shortcomings.A fluoride, because of its high electro negativity, forms stable binary or ternary complexes with many trivalent and tetravalent metal ions, and even with their complexes. It has been reported that Zr-EDTA can bind fluoride as well as oxo anions of arsenic and selenium by a ligand-exchange mechanism with coordinated water. [16][17][18] Hence, the combined use of Zr(H2O)2EDTA as an anion receptor and an appropriate chromophore was expected to give a good chemosensor for the nacked-eye detection of fluoride.In the present study, we observed that PV forms a ternary complex with Zr-EDTA by replacing water molecules, and produces an intense blue color. The blue color of this system readily shifts to orange red by the addition of fluoride, along with the release of free PV.These observations have successfully allowed us to construct a chemosensor for the visual detection of fluoride in aqueous solution. Experimental ReagentsAll reagents and solvents used were of analytical reagent grade. A stock solution of fluoride (0.0526 mol dm -3 ) was prepared by dissolving 99.9% NaF (Wako, Japan) in distilled water and standardized using the Alfusone method. 19 Zr(H2O)2EDTA·2H2O was prepared as a white crystal according to the procedure 20 and a 1 × 10 -2 M (M = mol dm -3 ) stock solution was prepared using distilled water. Pyrocatechol Violet was purchased from Dojindo Laboratories, Japan and a 1 × 10 -3 M stock solution was prepared by dissolving an appropriate amount in distilled water. Working solutions, as required, of the above reagents were prepared by app...

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Fluorimetric determination of fluoride in a flow assembly integrated on-line to an open/closed FIA system to remove interference by solid phase extraction

Cited by 38 publications

References 9 publications

A Recirculating Flow Injection Calorimetric Biosensor and Its Improved Performance Evaluation for Dichlorvos Detection

A Recirculating Flow Injection Calorimetric Biosensor and Its Improved Performance Evaluation for Dichlorvos Detection

Spectrophotometric Determination of Trace Amounts of Fluoride Using an Al-Xylenol Orange Complex as a Colored Reagent

Naked-Eye Detection of Fluoride Using Zr(IV)-EDTA Complex and Pyrocatechol Violet

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