This work describes the development of a solid phase spectrophotometry method in a mSI-LOV system for cadmium, zinc, and copper determination in freshwaters. NTA (Nitrilotriacetic acid) beads with 60 e160 mm diameter were packed in the flow cell of the LOV for a mSPE column of 1 cm length. The spectrophotometric determination is based on the colourimetric reaction between dithizone and the target metals, previously retained on NTA resin. The absorbance of the coloured product formed is measured, at 550 nm, on the surface of the NTA resin beads in a solid phase spectrophotometryapproach.The developed method presented preconcentration factors in the range of 11e21 for the metal ions. A LOD of 0.23 mg L1 for cadmium, 2.39 mg L1 for zinc, and 0.11 mg L1 for copper and a sampling rate of 12,13, and 15 h1 for cadmium, zinc, and copper were obtained, respectively. The proposed method was successfully applied to freshwater samples.