Preconcentration of cadmium, lead and nickel with Chelex-100, 8-hydroxyquinoline/silica gel and DDTC/Fullerene with a single flow system coupled to a tungsten coil electrothermal atomizer - Silva, Márcia Messias da; Krug, Francisco José; Oliveira, Pedro Vitoriano de; Arruda, Marco Aurélio Zezzi; Valcárcel Cases, Miguel; Gallego, Mercedes (Flow Analysis, 1997)