A novel sorbent, glycidyl methacrylate (GMA)-methyl methacrylate (MMA)-divinylbenzene (DVB) terpolymer functionalized with diethylenetriamine tetraacetic acid (DTTA), has been used for the sorption and preconcentration of Hg2+ from waters prior to its determination by inductively coupled plasma mass spectrometry. Various parameters such as solution pH, contact time, and sorbent amount were studied. Optimum sorption conditions were determined as pH of 7, contact time of 60 minutes, and sorbent amount/solution volume ratio of 1.5mgmL(-1). Batch-type equilibration studies have shown that the novel sorbent can be employed at a pH range resulting in quantitative sorption (>95%) at pH 4.0-8.0. For the quantitative elution of Hg2+ from the sorbent, 1.0M HCl was used. Langmuir isotherm model was found to characterize the uptake of Hg2+ by the novel sorbent. In addition, it was observed that the sorbent effectively removed Hg2+ ion even in the presence of several competitor ions (Pb2+, Cu2+, Zn2+, Fe3+, Ca2+, Mg2+, Ba2+, Ni2+, Al3+, Co2+, Mn2+, and Cd2+) with 99% removal. The validity of the method was verified both through the analysis of certified reference materials (BCR 422 and NIST 1547) and by spike recovery experiments. A recovery of 93% was obtained for ultrapure, tap and bottled drinking water samples even with a preconcentration factor of 100. Moreover, a good agreement was found for the results obtained with the proposed method and the certified values.