On-line preconcentration with mono-segmented elution for Cd, Cu, Ni, and Zn determination in soil samples by inductively coupled plasma optical emission spectrometry - Packer, Ana Paula Contador; Mattiazzo, Maria Emília; Bellato, Ana Cláudia Dias Sanches; Reis, Boaventura Freire dos (Atomic Spectroscopy, 2006)