Focused-microwave-induced combustion: investigation of KClO3 thermal decomposition as O-2 source

Autor(es)

Donati, George L. ^[1] ; Rosini, Fabiana ^[1] ; Nogueira, Ana Rita A. ^{[1, 2]} ; Nobrega, Joaquim A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Chem, Grp Appl Instrumental Anal, BR-13560970 Sao Carlos, SP - Brazil

^[2] Embrapa Pecuaria Sudeste, Brazilian Agr Minist, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ANALYTICAL METHODS; v. 3, n. 7, p. 1688-1691, JUL 2011.
• Citações Web of Science: 4

Resumo

Potassium chlorate is proposed here as a chemical source of O(2) in focused-microwave-induced combustion. The thermal decomposition of this compound generates enough O(2) to maintain the combustion and participate in gas phase reactions responsible for HNO(3) regeneration. An animal feed concentrate is the reference material and test sample used. Important parameters such as HNO(3) concentration in the absorbing solution, volumes of igniting and oxidizing agents added to the sample, and microwave total incidence time were evaluated using a multivariate approach. The method efficiency was evaluated by determining both the residual carbon content (RCC) in the digestates and the recoveries of Ca, Mg, Mn, P and Zn using inductively coupled plasma optical emission spectrometry. Recoveries in the 82.3-102% range were obtained for all elements studied using 5 mL of an absorbing solution with 5.0 mol L(-1) of HNO(3), and adding 110 mu L of NH(4)NO(3) 6.0 mol L(-1) plus 140 mu L of KClO(3) 0.5 mol L(-1) to the solid sample, in a 7 min digestion program. A RCC value of 20% and a final acid concentration of 0.19 mol L(-1) were obtained in the combustion of 100 mg of sample under optimized conditions. These preliminary results show the capabilities of a simple, inexpensive method with potential for different applications in procedures taking no longer than a few minutes. It is compatible with commercially available focused-microwave systems and requires no instrumental modification for its implementation. (AU)

• Processo FAPESP: 10/50238-5 - Determinacao de fosforo, enxofre e silicio em biodiesel usando espectrometro de massa acoplado ao plasma induzido com interface de colisao e reacao
• Beneficiário: George Luis Donati
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 06/59083-9 - Espectrometria de massa acoplada ao plasma induzido: aspectos fundamentais e aplicações
• Beneficiário: Joaquim de Araújo Nóbrega
• Modalidade de apoio: Auxílio à Pesquisa - Temático