Methodological Validation for the Determination of Ca, Cr, Mg and Mn in Umbilical Cord and Maternal Blood (City of Vale do Paraíba, São Paulo, Brazil)

This investigation focused on the validation of the methodology used in determining the presence of specific elements in human blood. Concentrations of macro- and micronutrients in umbilical blood (UCB) samples from 37 lactating volunteers who gave birth in the city of Taubaté, State of São Paulo, Brazil. The determinations of Ca and Mg were carried out in a flame atomic absorption spectrometer (FAAS) and those of Cr and Mn in a graphite furnace atomic absorption spectrometer (GFAAS). A procedure for preparing samples was optimized and evaluated. Standard addition methods and determinations by ICP OES were used to validate the analytical procedures. An acetylene/air mixture was optimized at 2.0/17.0 L min-1 (Ca and Mg). Pyrolysis and atomization temperatures for Cr were at 1400℃ and 2100℃, respectively, and for Mn at 1300℃ and 1700℃, respectively. The most efficient chemical modifier was a solution containing 5 g of Pd + 3 g of Mg(NO₃)₂. Characteristic masses for Cr and Mn were 2.6 and 2.7 pg, respectively. The methods presented high analytical efficiency in the determination of Ca, Cr, Mg and Mn (recovery from 98.68% to 108.22 %). Minimal data variations in repeatability and reproducibility indicated significient precision and accuracy for the proposed methodology. The placenta did not block transport of elements from mother to fetus. The contents of the elements analyzed in the UCB were compared to those detected in maternal blood (MB). Most of the children exhibited normal weight (from 2.5 to 3.0 kg) as per the Brazilian Ministry of Health standards. Such results indicate that the levels of concentrations of the elements found in the UCB did not affect the weights of the neonates.