For the first time, ferrofluid based dispersive-solid phase extraction (D-SPE) has been applied for determination of trace levels of dyes in aqueous and fish samples. The contaminant used as a model compound was crystal violet (CV), a cationic dye, and was preconcentrated without any derivatization or ion-pair formation. The method is based on rapid injection of ferrofluid into the aqueous sample by a syringe. The sample preparation time is decreased by the fact that the sorbent dispersed in the bulk solution and extraction can be achieved very fast. In this way, the separation of sorbent from the aqueous bulk was achieved by a magnet, and no centrifugation is required. These significant features which obtained with this method are of key interest for routine trace laboratory analysis. The influence of different variables on D-SPE was investigated. Under optimum conditions, the calibration graph was linear over the range of 3.3-90 mu g L-1, and the enrichment factor (EF) 267 was obtained. Detection limit was 1.51 mu g L-1 (n = 7), and the relative standard deviation of 5.6% at 50 mu g mL(-1) was obtained (n = 7). The proposed method was successfully applied for the determination of crystal violet in various samples. (C) 2013 Elsevier Inc. All rights reserved.