A new chelating resin was synthesized by immobilizing 4-(2-thiazolylazo) resorcinol (TAR) on to a styrene divinylbenzene copolymer. This material was examined for on-line solid phase extraction/preconcentration of Cd, Co, Cu, Ni, Pb, and Zn in seawater and fish otoliths for determination by inductively plasma mass spectrometry (ICP-MS). A volume of 5.0mL sample solution was loaded on to a mini-column of the resin at 2.0mLmin(-1) via a sequential injection system. The optimum pH for multielement preconcentration was around pH 5.5. Recoveries were better than 96% in artificial seawater. Elution was achieved with 1.0mL of 0.75molL(-1) HNO3. The resin possesses a large sorption capacity ranging from 82.0 mu molg(-1) for Pb to 319 mu molg(-1) for Cu. The detection limits (3 sigma) varied between 0.0016 mu gL(-1) (Cd) and 0.015 mu gL(-1) (Zn) for preconcentration of 5.0mL blank solutions (pH 5.5). Relative standard deviation for three replicate runs was between 0.3% (Cd) and 6% (Zn) at the 1.0 mu gL(-1) level. The procedure was validated by analysis of a nearshore seawater and a fish otoliths certified reference material, and employed for coastal seawater and estuarine water samples.