In the present paper, an on-line preconcentration procedure for determination of cadmium, copper and zinc by thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) is proposed. Amberlite XAD-4 functionalized with 3,4-dihydroxybenzoic acid (XAD4-DHB) packed in a minicolumn was used as sorbent material. The metals were retained on the XAD-DHB resin, from which it could be eluted directly to the thermospray flame furnace system. The detection limits were 28 (Cd), 100 (Cu) and 77 ng L-1 (Zn) for 60 s preconcentration time, at a sample flow rate of 7.0 mL min(-1). Enrichment factors were 102, 91 and 62, for cadmium, copper and zinc, respectively. The procedure has been applied successfully to metal determination in biological standard reference materials. (C) 2008 Elsevier B.V. All rights reserved.