Improved recovery of fluoride in plant material using a low temperature sealed chamber digestion technique in conjunction with a fluoride ion‐specific electrode

Keerthisinghe, G.; McLaughlin, M. J.; Randall, P. J.

doi:10.1080/00103629109368539

Cited by 10 publications

(4 citation statements)

References 18 publications

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“…Plant samples for determination of F and other elements were digested with concentrated HNO 3 in a microwave digestion unit 17. F concentration was measured by a combination fluoride‐selective electrode after the digestion solution was mixed with total ionic strength adjusting buffer (TISAB).…”

Section: Methodsmentioning

confidence: 99%

Uptake of fluoride by tea plant (Camellia sinensis L) and the impact of aluminium

Ruan

Shi

et al. 2003

J Sci Food Agric

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Tea plant (Camellia sinensis L) accumulates large amounts of fluoride in mature leaves from soils of normal fluoride availabilities, but the properties of fluoride absorption by this plant species are not well understood. The present study examined the characteristic of fluoride uptake by tea plants and the impact of Al with solution and soil experiments. The results showed that the fluoride taken up by tea plants was largely and readily transported, in particular to the leaves. The fluoride in leaves increased linearly with fluoride concentrations in the uptake solution (R 2 = 0.75, P < 0.001) or in the soil (R 2 = 0.88, P < 0.001), whereas those in root and stem were only marginally influenced. Including Al in solution or adding Al to the soil apparently increased the uptake and translocation of fluoride to the leaves. The concentrations of fluoride in the leaves were significantly (P < 0.05) increased by 19.1% or 37.7% when 18.5 µmol l −1 Al or 74.1 µmol l −1 Al respectively was included in the uptake solution, compared with the control without Al during an uptake period of 22 h. Similarly, Al application (100 mg kg −1 ) to soil led to significantly higher fluoride concentrations in mature leaves and new shoots (one bud with three leaves). By contrast, the concentrations of Al in leaves in solution and soil experiments were not affected by fluoride and Al treatments. Nevertheless, higher Al concentrations after Al and fluoride additions were observed in the new shoots in soil experiments.

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Section: Methodsmentioning

confidence: 99%

Uptake of fluoride by tea plant (Camellia sinensis L) and the impact of aluminium

Ruan

Shi

et al. 2003

J Sci Food Agric

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“…For F determinations, plant samples (0´2±0´5 g) were digested with 5 mL concentrated HNO 3 in a microwave digestion unit equipped with a temperature control system (Model Mars 5, CEM Corporation, Matthews, USA) and measured with a¯uoride ion selective electrode (F-ISE) as previously used by Stevens et al (1995), but with modi®cations. After cold digestion in the sealed vessels for one night, the samples were digested at 120°C as described by Keerthisinghe et al (1991), for 20 min. The digest solutions were diluted with deionized water and a 5-mL aliquot was added to 20 mL 1´5 mol L ±1 trisodium citrate (pH 5´25) for millivolt potential measurements.…”

Section: Analysesmentioning

confidence: 99%

The Impact of pH and Calcium on the Uptake of Fluoride by Tea Plants (Camellia sinensis L.)

Jiang-yun¹

2004

Annals of Botany

103

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F uptake by tea plants, which are inherently able to accumulate large quantities of F, was affected both by pH and by Ca levels in the medium. The reduced F uptake following Ca application appeared not to be due simply to the precipitation of CaF2 in solution and soil or to the complexing of Ca and F in roots, although these factors cannot be dismissed. It was more likely due to the effect of Ca on the properties of cell wall or membrane permeability in the solution experiments, and to alteration of F speciations and their quantities in soil solutions following Ca application.

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“…The first assays of acid digestion with nitric acid in closed vessels (Teflon, 120 °C, 6 h) provided higher fluoride recoveries in plant samples than those found with acid or alkali digestion in open systems. 25 Those authors attributed the improvement to the complete solubilization of the fluoride in the sample and the elimination of losses through volatilization. The use of closed systems in microwaves for the analysis of fluoride was not described until 1998, by Grobler and Louw, who used Parr bombs to obtain excellent recoveries in various samples, including food.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Quantification of Fluoride in Food by Microwave Acid Digestion and Fluoride Ion-Selective Electrode

Rocha

Rojas

Clemente

et al. 2013

J. Agric. Food Chem.

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To quantify fluoride in food it is necessary to extract the fluoride from the matrix. Dry ashing (alkali fusion) and facilitated diffusion are the methods most commonly used, but their application requires lengthy treatments. The present study proposes the use of a microwave oven and 7 mol/L nitric acid for simple, rapid digestion of foods for fluoride analysis. The analyte is subsequently quantified by fluoride ion-selective electrode. The various steps of the method were optimized and an in-house validation was performed. The limit of quantification (0.130 mg/kg), trueness (92%), recovery (84-101%), and precision (1-8%) were determined. These analytical characteristics are satisfactory and show the suitability of the method for analysis of fluoride in foods of various kinds. The method's ease of application and the use of equipment normally found in food analysis laboratories may help to further increase research on fluoride concentrations in foods consumed by the population.

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Improved recovery of fluoride in plant material using a low temperature sealed chamber digestion technique in conjunction with a fluoride ion‐specific electrode

Cited by 10 publications

References 18 publications

Uptake of fluoride by tea plant (Camellia sinensis L) and the impact of aluminium

Uptake of fluoride by tea plant (Camellia sinensis L) and the impact of aluminium

The Impact of pH and Calcium on the Uptake of Fluoride by Tea Plants (Camellia sinensis L.)

Quantification of Fluoride in Food by Microwave Acid Digestion and Fluoride Ion-Selective Electrode

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