Influence of microwave heating on fluoride, chloride, nitrate and sulfate concentrations in water

TALANTA

卷:85

Article

Figueiredo, Eduardo Costa²  Dias, Jailson Cardoso^1,3  Kubota, Lauro Tatsuo^1,3  Korn, Mauro⁴  Oliveira, Pedro Vitoriano⁵  Zezzi Arruda, Marco Aurelio^1,3,6 

[1] Univ Campinas UNICAMP, Dept Analyt Chem, Inst Chem, BR-13083970 Campinas, SP, Brazil

[2] Fed Univ Alfenas UNIFAL MG, Fac Pharmaceut Sci, BR-37130000 Alfenas, MG, Brazil

[3] Univ Campinas Unicamp, Natl Inst Sci & Technol Bioanalyt, Inst Chem, BR-13083970 Campinas, SP, Brazil

[4] Bahia State Univ UNEB, NQA Dept Earth & Exact Sci, BR-41150000 Salvador, BA, Brazil

[5] Univ Sdo Paulo USP, Inst Chem, BR-05508000 Sao Paulo, Brazil

[6] Univ Campinas UNICAMP, Grp Spectrometry Sample Preparat & Mechanizat GEP, Inst Chem, BR-13083970 Campinas, SP, Brazil

关键词: Microwave heating;    Anions generation;    PFA vessel;    Fluoride;    Chloride;    Nitrate;    Sulfate;   

DOI  :  10.1016/j.talanta.2011.08.003

来源: Elsevier

【 摘 要 】

This paper describes a study about the influence of microwave radiation using closed vessels on fluoride, chloride, nitrate and sulfate concentrations in aqueous media. The experiments were processed by heating water using PFA vessels and a microwave cavity oven, determining the anions by ion chromatography. The influence of the exposure time, the atmospheric composition, the kind of heating (water bath or microwave radiation) and the possible formation of hydrogen peroxide were investigated. The limits of quantification for fluoride, chloride, nitrate and sulfate were respectively of 0.17, 0.15, 0.55 and 0.57 mu g L-1, and precision, expressed as RSD, was <4% for all considered anions. The hydrogen peroxide was quantified by spectrophotometry, and the limit of quantification and precision were 24 mu g L-1 and <5% (n = 10), respectively. The results demonstrate a significant increase in the anion concentration levels (between 63 and 89%) when microwave heating was used in comparison with heating by water bath. In addition, these changes observed can be mainly attributed to the species transfers, either between gaseous (atmospheric gases) and liquid (water) phases for nitrate, or between vessels walls and water for fluoride, chloride and sulfate. Additionally, hydrogen peroxide concentration higher than 45 mu g L-1 was determined when water was exposed to microwave radiation. (C) 2011 Elsevier B.V. All rights reserved.

【 授权许可】

Free