Electroanalytical determination of cadmium and lead in deciduous teeth after microwave oven digestion

A method using differential pulse anodic stripping voltammetry after microwave oven digestion was developed for the simultaneous determination of Cd(II) and Pb(II) in the deciduous teeth of children. Each tooth was weighed; deposited in a 120 mL capped Teflon vessel with 5 mL 65% nitric acid, Suprapur analytical grade; and digested in a 2-step microwave oven for 15 min. The detection limits for Cd(II) and Pb(II) in the final solution were 0.078 and 0.323 microg/L, and the quantitation limits 0.394 and 1.613 microg/L, respectively, with a linearity range of 2 microg/L for Cd(II) and 23.3 microg/L for Pb(II). The sensitivity was 2.51 nA/microg-L and 1.37 nA/microg-L, for Cd(II) and Pb(II). The main advantages of this technique are a complete and satisfactory dissolution of the tooth material with the proposed microwave oven digestion procedure, without sample pretreatments, such as drying, ashing, or powdering. The voltammetric procedure proved to be well designed because of significant goodness of fit to a linear model, and the accuracy of the method was established as compared with standard reference material. The methodology has enabled us to study Cd(II) and Pb(II) in 371 deciduous teeth from school children in Cartagena, Spain.