Toxic metals (Pb and Cd) and their respective antagonists (Ca and Zn) in infant formulas and milk marketed in Brasilia, Brazil.

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.

Indirect determination of dichlorodiphenyltrichloroethane (DDT) after dechlorination with magnesium/palladium bimetallic particles and potentiometric measurements.

Determination of chlorine ions of pesticides was performed after dechlorination reaction using a palladium/magnesium system. Chlorine ions were quantified by potentiometry with ion-specific electrode. Rates of dechlorination of 100 microg of DDT as a function of reaction time and percent (wt/wt) of palladium deposited on the magnesium particles were determined.

Modification of a reaction vessel for the determination of total mercury in hair by cold vapor atomic absorption spectrometry.

A classical cold vapor atomic absorption spectrometric (CVAAS) method for the determination of total mercury in blood has been previously adapted for application to samples of human hair. The reaction vessel specified in the original adaptation was, however, large and difficult to use with small hair samples. In the present study, the reaction vessel has been modified and reduced in size and the protocols have been optimized in order to provide an analytical method that is more efficient, less time-consuming, and gives lower blank values than the original adaptation.

Determination of Se(IV) by anodic stripping voltammetry using gold electrodes made from recordable CDs.

This work presents a simple, reproducible and low cost method, employing differential pulse anodic stripping voltammetry, for determination of selenium(IV). A gold electrode obtained from recordable compact disks (CD-R) was used to evaluate the voltammetric behavior of the metallic ion in 0.1molL(-1) HClO(4).

The binding of zinc (II) to a double-stranded oligodeoxyribonucleotide. A voltammetric study.

Binding of zinc to a 19 mer double-stranded oligodeoxyribonucleotide was investigated by anodic stripping voltammetry and cyclic voltammetry in order to understand the roles of zinc in DNA cleavage catalyzed by mung bean nuclease. These methods rely on the direct monitoring of zinc oxidation current in the absence and in the presence of the oligo. Zinc titration curves with the ds-oligodeoxyribonucleotide were obtained in concentrations ranging from 3.

Investigations on the binding of mercury ions to albumins employing differential pulse voltammetry.

Binding of mercury to BSA and Ovalbumin was investigated by Differential Pulse Voltammetry. The method relies on the direct monitoring of peak current variation due to mercury oxidation in the presence of these two albumins. Linear calibration graphs were obtained for both BSA and Ovalbumin in concentrations ranging from 2.