Potentiometric determination of fluoride in geological and biological samples following pyrohydrolytic decomposition

Dressler, Valderi L.; Pozebon, Dirce; Flores, Éder Lisandro Moraes; Paniz, José Neri Gottfried; Flores, Érico M.M.

doi:10.1016/s0003-2670(02)00550-0

Cited by 53 publications

(55 citation statements)

References 16 publications

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“…7 Total ionic strength adjustment buffer (TISAB) was prepared by mixing 58 g of sodium chloride (Merck), 4 g of 1,2-cyclohexilenediaminetetraacetic acid (Merck) and 57 mL of acetic acid (Merck) in 500 mL of water. The pH of this solution was adjusted to 5.5 with a 10% (m/v) sodium hydroxide (Merck) solution.…”

Section: Reagentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Techniques such as spectrophotometry, 6 potentiometry using ion-selective electrode (ISE), 7 ion chromatography, 8,9 inductively coupled plasma optical emission spectrometry (ICP OES), 10,11 and inductively coupled plasma mass spectrometry (ICP-MS) [12][13][14][15] can be employed for Br, I and F determination. Fluorine can also be determined by graphite furnace molecular absorption spectrometry, 16 ion chromatography 10,17 and capillary electrophoresis.…”

Section: Introductionmentioning

confidence: 99%

“…20,21 Sample preparation is usually the bottleneck in halogen determination by ICP-MS, due to memory effects caused by high volatility of halogens in acidic solutions. [22][23][24] Therefore, alkaline fusion, 20 dilution or dispersion in alkaline solution, distillation (for fluorine), combustion in bombs, 25 microwave-induced combustion (MIC) 9,26-29 and pyrohydrolysis 7,17,[30][31][32] are used for sample preparation.Pyrohydrolysis is a simple alternative for decomposition of organic 7,19,31,33 and inorganic 34-36 materials when halogens determination is intended. The main advantages are the possibility of matrix separation and the use of a diluted alkaline solution for analytes absorbing.…”

mentioning

confidence: 99%

“…7,33 According to the literature, usually the use of an accelerator is necessary for halogens release from inorganic sample matrixes. 7,24,33,36 However, for other samples, like coal and petroleum coke, halogens are released without any auxiliary reagent. 19,33,38 Figure 2.…”

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confidence: 99%

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Determination of bromine, fluorine and iodine in mineral supplements using pyrohydrolysis for sample preparation

Taflik

Duarte

Flores

et al. 2012

J. Braz. Chem. Soc.

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Neste trabalho foi utilizada a piroidrólise para a decomposição de suplemento mineral utilizado na nutrição animal, para a posterior determinação de F, Br e I. Flúor foi determinado por potenciometria utilizando eletrodo íon-seletivo para fluoreto, enquanto que Br e I foram determinados por espectrometria de massa com plasma indutivamente acoplado. Os principais parâmetros que influenciam a piroidrólise foram investigados e, após a devida avaliação dos mesmos, foram fixadas as seguintes condições: a temperatura do reator em 1000 °C durante 10 min; a proporção entre a massa de amostra e a massa de acelerador em 1 + 5 e a vazão do gás carreador em 200 mL min -1 . A exatidão do método foi avaliada usando teste de recuperação do analito e análise de materiais de referência certificados de rocha fosfática e de solo. O método foi aplicado para análise de suplemento mineral. Os limites de quantificação foram de 16, 0,3 e 0,07 µg g -1 para F, Br e I, respectivamente. Assim, usando-se um método relativamente simples e de baixo custo é possível a decomposição de até 5 amostras por hora. Portanto, a piroidrólise pode ser usada como um método de rotina para o preparo de amostra de suplemento mineral para a determinação de F, Br e I.Pyrohydrolysis was employed for mineral supplements decomposition prior to F, Br and I determination. Fluoride determination was carried out by potentiometry using a fluoride-ion selective electrode, whereas Br and I were determined by inductively coupled plasma mass spectrometry. The main parameters that influence on pyrohydrolysis were investigated. After evaluation, the following conditions were established: reactor temperature of 1000 °C during 10 min; sample plus accelerator mass ratio of 1 + 5 and carrier gas (air) flow rate of 200 mL min -1 . The accuracy of the proposed method was evaluated by analyte recovery tests and analysis of certified reference materials of phosphate rock and soil. Commercial mineral supplement samples were analyzed. The limits of quantification were 16, 0.3 and 0.07 µg g -1 for F, Br and I, respectively. By using a relatively simple and low cost pyrohydrolysis system up to 5 samples can be processed per hour. The developed sample preparation procedure can be routinely employed for F, Br and I determination in mineral supplements. Keywords: pyrohydrolysis, halogens determination, mineral supplement IntroductionSeveral elements are essential for animals growing and breeding. Those elements required in high amounts are called macronutrients (Ca, Cl, K, P, Mg, Na, and S) and those elements required in low concentrations are called micronutrients (Co, Cu, Fe, I, Mn, Mo, Se, Zn, and eventually Cr and F are included in this group). 1 The main functions of essential elements in the organism are associated to the structural composition of body and enzymatic and hormonal processes.Although F usually increases the strength of bones and teeth, this element is generally not considered as essential. 1 Fluorine is usually present as a contaminant since it is Taflik et al. 489 ...

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Section: Reagentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Determination of bromine, fluorine and iodine in mineral supplements using pyrohydrolysis for sample preparation

Taflik

Duarte

Flores

et al. 2012

J. Braz. Chem. Soc.

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An Extractive‐Spectrophotometric Method for Determination of Fluoride Ions in Natural Waters Based on its Bleaching Effect on the Iron (III)‐Thiocyanate Complex

Farajzadeh

2004

J Chinese Chemical Soc

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An extractive-spectrophotometric method based on the bleaching effect of F -ions on the iron (III)-thiocyanate complex extracted into methyl iso-butyl keton (MIBK) is proposed for the determination of fluoride ions in natural waters. This method is a simple and rapid method and there is no need for special and expensive reagents. The experimental conditions such as SCN -concentration, pH and kind of solvent were optimized, and we found that 0.15 M SCN -, pH = 5 and MIBK are the best selections. Limit of detection is 0.1 mg F -/L with a linear dynamic range 0.5-7 mg/L which covers optimum concentration of F -ions in drinking water (0.7-1.2 mg/L). Interference of Fe 3+ and Al 3+ ions was easily eliminated by the extractive procedure using a solution of oxine in chloroform. Finally, the proposed method was used in determination of fluoride content of some real water samples and the obtained results compared with those obtained from the standard method. No significant differences were observed between them.

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Analytical methods for the determination of halogens in bioanalytical sciences: a review

et al. 2013

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Fluorine, chlorine, bromine, and iodine have been studied in biological samples and other related matrices owing to the need to understand the biochemical effects in living organisms. In this review, the works published in last 20 years are covered, and the main topics related to sample preparation methods and analytical techniques commonly used for fluorine, chlorine, bromine, and iodine determination in biological samples, food, drugs, and plants used as food or with medical applications are discussed. The commonest sample preparation methods, as extraction and decomposition using combustion and pyrohydrolysis, are reviewed, as well as spectrometric and electroanalytical techniques, spectrophotometry, total reflection X-ray fluorescence, neutron activation analysis, and separation systems using chromatography and electrophoresis. On this aspect, the main analytical challenges and drawbacks are highlighted. A discussion related to the availability of certified reference materials for evaluation of accuracy is also included, as well as a discussion of the official methods used as references for the determination of halogens in the samples covered in this review.

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Potentiometric determination of fluoride in geological and biological samples following pyrohydrolytic decomposition

Cited by 53 publications

References 16 publications

Determination of bromine, fluorine and iodine in mineral supplements using pyrohydrolysis for sample preparation

Determination of bromine, fluorine and iodine in mineral supplements using pyrohydrolysis for sample preparation

An Extractive‐Spectrophotometric Method for Determination of Fluoride Ions in Natural Waters Based on its Bleaching Effect on the Iron (III)‐Thiocyanate Complex

Analytical methods for the determination of halogens in bioanalytical sciences: a review

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