Entity

Time filter

Source Type


Ferreira A.B.,Instituto Tecnologico E Of Pesquisas Do Estado Of Sergipe Itps | Santos J.O.,Instituto Federal Of Ciencia E Tecnologia Of Sergipe | Souza S.O.,Instituto Tecnologico E Of Pesquisas Do Estado Of Sergipe Itps | Junior W.N.S.,Instituto Tecnologico E Of Pesquisas Do Estado Of Sergipe Itps | And 2 more authors.
Microchemical Journal | Year: 2012

Measurements of trace elements in tree bark were used to investigate pollution caused by emissions from two cement production plants in the vicinity of the cities of Laranjeiras and Nossa Senhora do Socorro (Sergipe State, northeast Brazil). Samples of tree bark were collected across a wide area within the municipalities of Machado, Estivas, and Estivas II, as well as close to the two cement plants. Analyses were carried out by EDXRF to determine the concentrations of Al, Ca, Cu, Fe, K, Mg, S, Sr, and Zn in the tree barks. The resulting data were used to generate distribution maps of element concentrations, which enabled identification of pollution hotspots. The results indicated that emissions from the cement industry affect the region as a whole, as demonstrated by accumulation of trace elements in the tree barks. © 2011 Elsevier B.V.. Source


De Oliveira Souza S.,Federal University of Sergipe | Da Costa S.S.L.,Federal University of Sergipe | Da Costa S.S.L.,Federal University of Alagoas | Santos D.M.,Federal University of Sergipe | And 6 more authors.
Spectrochimica Acta - Part B Atomic Spectroscopy | Year: 2014

An analytical method for simultaneous determination of macronutrients (Ca, Mg, Na and P), micronutrients (Cu, Fe, Mn and Zn) and trace elements (Al, As, Cd, Pb and V) in mineral fertilizers was optimized. Two-level full factorial design was applied to evaluate the optimal proportions of reagents used in the sample digestion on hot plate. A Doehlert design for two variables was used to evaluate the operating conditions of the inductively coupled plasma optical emission spectrometer in order to accomplish the simultaneous determination of the analyte concentrations. The limits of quantification (LOQs) ranged from 2.0 mg kg- 1 for Mn to 77.3 mg kg- 1 for P. The accuracy and precision of the proposed method were evaluated by analysis of standard reference materials (SRMs) of Western phosphate rock (NIST 694), Florida phosphate rock (NIST 120C) and Trace elements in multi-nutrient fertilizer (NIST 695), considered to be adequate for simultaneous determination. Twenty-one samples of mineral fertilizers collected in Sergipe State, Brazil, were analyzed. For all samples, the As, Ca, Cd and Pb concentrations were below the LOQ values of the analytical method. For As, Cd and Pb the obtained LOQ values were below the maximum limit allowed by the Brazilian Ministry of Agriculture, Livestock and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento - MAPA). The optimized method presented good accuracy and was effectively applied to quantitative simultaneous determination of the analytes in mineral fertilizers by inductively coupled plasma optical emission spectrometry (ICP OES). © 2014 Elsevier B.V. Source


Da Costa S.S.L.,Federal University of Sergipe | Da Costa S.S.L.,Federal University of Alagoas | Lima Pereira A.C.,Federal University of Sergipe | Andrade Passos E.,Federal University of Sergipe | And 4 more authors.
Talanta | Year: 2013

Experimental design methodology was used to optimize an analytical method for determination of the mineral element composition (Al, Ca, Cd, Cr, Cu, Ba, Fe, K, Mg, Mn, P, S, Sr and Zn) of dog and cat foods. Two-level full factorial design was applied to define the optimal proportions of the reagents used for microwave-assisted sample digestion (2.0 mol L-1 HNO3 and 6% m/v H2O2). A three-level factorial design for two variables was used to optimize the operational conditions of the inductively coupled plasma optical emission spectrometer, employed for analysis of the extracts. A radiofrequency power of 1.2 kW and a nebulizer argon flow of 1.0 L min-1 were selected. The limits of quantification (LOQ) were between 0.03 μg g-1 (Cr, 267.716 nm) and 87 μg g-1 (Ca, 373.690 nm). The trueness of the optimized method was evaluated by analysis of five certified reference materials (CRMs): wheat flour (NIST 1567a), bovine liver (NIST 1577), peach leaves (NIST 1547), oyster tissue (NIST 1566b), and fish protein (DORM-3). The recovery values obtained for the CRMs were between 80±4% (Cr) and 117±5% (Cd), with relative standard deviations (RSDs) better than 5%, demonstrating that the proposed method offered good trueness and precision. Ten samples of pet food (five each of cat and dog food) were acquired at supermarkets in Aracaju city (Sergipe State, Brazil). Concentrations in the dog food ranged between 7.1 mg kg-1 (Ba) and 2.7 g kg-1 (Ca), while for cat food the values were between 3.7 mg kg-1 (Ba) and 3.0 g kg-1 (Ca). The concentrations of Ca, K, Mg, P, Cu, Fe, Mn, and Zn in the food were compared with the guidelines of the United States' Association of American Feed Control Officials (AAFCO) and the Brazilian Ministry of Agriculture, Livestock, and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento - MAPA). © 2013 Elsevier B.V. Source

Discover hidden collaborations