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)

Abstract

This investigation focused on the validation o f the methodology used in determining the presence of specific elements in human blood. Concentrations of macro-and micronutrients in umbilical b lood (UCB) samples fro m 37 lactating volunteers who gave birth in the city of Taubaté , State of Sã o Paulo, Brazil. The determinations of Ca and Mg were carried out in a flame ato mic absorption spectrometer (FAAS) and those of Cr and Mn in a graphite furnace ato mic 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 atomizat ion temperatures for Cr were at 1400°C and 2100°C, respectively, for Mn at 1300°C and 1700°C, 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 fro m 98.68% to 108.22 %). M inimal data variations in repeatability and reproducibility indicated significient precision and accuracy for the proposed methodology. The placenta did not block transport of elements fro m mother to fetus. The contents of the elements analyzed in the UCB were co mpared to those detected in maternal blood (M B). Most of the children exh ibited normal weight (fro m 2.5 to 3.0 kg) as per the Brazilian Min istry of Health standards. Such results indicate that the levels of concentrations of the elements in the UCB did not affect the weights of the neonates.