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de Castro C.S.P.,Laboratorio Of Tecnologias Para A Seguranca Alimentar | Arruda A.F.,Federal University of Goais | da Cunha L.R.,Laboratorio Of Tecnologias Para A Seguranca Alimentar | de Souza J.R.,University of Brasilia | And 2 more authors.
International Journal of Environmental Research and Public Health | Year: 2010

In non-ideal scenarios involving partial or non-breastfeeding, cow's milk-based dairy products are mainstream in infant feeding. Therefore, it is important to study the concentrations of potentially neurotoxic contaminants (Pb and Cd) and their respective counteracting elements (Ca and Zn) in infant dairy products. Fifty-five brands of infant formulas and milk sold in Brasilia, Brazil were analyzed. The dairy products came from areas in the central-west (26%), southeast (29%) and south of Brazil (36%) extending as far as Argentina (7%) and the Netherlands (2%). For toxic Pb and Cd, median concentrations in powdered samples were 0.109 mg/kg and 0.033 mg/kg, respectively; in fluid samples median Pb concentration was 0.084 mg/kg, but median Cd concentration was below the limit of detection and overall values were below reference safety levels. However, 62% of these samples presented higher Pb concentration values than those established by FAO/WHO. Although the inverse correlation between Cd and Zn (Spearman r = -0.116; P = 0.590) was not statistically significant, the positive correlation between Ca and Pb was (Spearman r = 0.619; P < 0.0001). Additionally, there was a significant correlation between Pb and Cd. Furthermore, the study also revealed that provision of the essential trace element Zn in infant formulas can provide adequate amounts of the recommended daily requirements. Infant formulas and milk sold for consumption by infants and children can be an efficient tool to monitor neurotoxic metal risk exposure among young children. Source


Magarelli G.,Laboratorio Of Tecnologias Para A Seguranca Alimentar | da Silva J.G.,Laboratorio Of Tecnologias Para A Seguranca Alimentar | da Silva J.G.,University of Brasilia | Sousa Filho I.A.D.,Laboratorio Of Tecnologias Para A Seguranca Alimentar | And 4 more authors.
Microchemical Journal | Year: 2013

A highly sensitive and selective differential pulse voltammetric (DPV) method based on the oxidation of caffeic acid in a glassy carbon electrode is presented for determination of total phenolic acids (TPAs). Under optimized conditions (0.2M phosphate buffer, pH 3, 50mV pulse amplitude, 50mVs-1 scan rate), the oxidation peak current (Ipa) of caffeic acid is linear (Ipa(A)=-4.15×10-8+0.97 [Caffeic acid]) to caffeic acid concentration in the range from 1.0×10-7 to 1.0×10-6M, with a correlation coefficient of 0.9985. The detection and quantitation limits obtained were 6.8×10-8M and 1.0×10-7M, respectively. The repeatability and intermediate precision of DPV method were acceptable (Relative Standard Deviation (RSD) <10%). The absence of the matrix effect on the determination of TPAs by DPV method was attested by F-test and t-test (95% confidence level). The method was successfully applied to the determination of TPAs in five cotton cultivars, with recoveries of 94-104% (RSD <2%). © 2012 Elsevier B.V. Source


Magarelli G.,Laboratorio Of Tecnologias Para A Seguranca Alimentar | Lima L.H.C.,Laboratorio Of Tecnologias Para A Seguranca Alimentar | da Silva J.G.,Laboratorio Of Tecnologias Para A Seguranca Alimentar | da Silva J.G.,University of Brasilia | And 2 more authors.
Microchemical Journal | Year: 2014

Two highly sensitive differential pulse voltammetric (DPV) methods based on the oxidation of genistein and rutin in a glassy carbon electrode is presented. Under optimized conditions (0.2M phosphate buffer, pH6.0, 50mV pulse amplitude, 50mVs-1 scan rate), the oxidation peak currents (Ip) of genistein and rutin are linear (Ipa(A)=5.0×10-8+0.056 [genistein] r=0.9969; Ipa(A)=-3.0×10-8+0.112 [rutin] r=0.9974) to genistein and rutin concentrations in the range of 1.0×10-6-6.0×10-6M and 1.0×10-6-1.2×10-5M, respectively. The detection limits obtained for genistein and rutin were 6.1×10-7M and 3.8×10-7M, respectively. The quantitation limit for both genistein and rutin was 1.0×10-6M. The repeatability of DPV methods was acceptable (relative standard deviation (RSD)<10%). The presence of matrix effect on the genistein determination and the absence of matrix effect on the rutin determination were attested by t-test (95% confidence level). The DPV methods were applied to the determination of rutin and total isoflavones in a Brazilian soybean cultivar (BRS 216 Flora) in ten different growth stages, with recoveries of 73-109%. Flora exhibited concentration levels of rutin and total isoflavones in leaves, seeds and pods ranging from 0.44 to 1.7mgg-1 and 72 to 128μgg-1, respectively. © 2014 Elsevier B.V. Source

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