Elsevier, Electrochimica Acta, 2(55), p. 475-479, 2009
DOI: 10.1016/j.electacta.2009.08.053
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Fast and simple quantitative determination in dispersed systems (layered double hydroxides – LDHs – suspensions in aqueous solutions) was performed by a procedure that couples flow injection and ampero-metric detection (FI-AM). LDH dispersions are injected in a continuous flow (1 mL min −1) of 0.05 mol L −1 KNO 3 solution and [Cu(H 2 O) 6 ] 2+ , used as a probe, is detected at a glassy carbon electrode housed in a flat electrochemical cell. The current intensity, recorded at the selected working potential (−0.25 V vs Ag/AgCl/NaCl (3 mol L −1)), presents a linear relationship with [Cu(H 2 O) 6 ] 2+ concentration and the pro-cedure offers high sensitivity (slope = 0.036 A/(mol L −1)), a low detection limit (=0.7 mol L −1) and a wide quantification range (4–200 mol L −1). The method was applied to [Cu(H 2 O) 6 ] 2+ determination in two particular LDH-aqueous solution dispersed systems: (1) [Cu(H 2 O) 6 ] 2+ scavenging by etilendiammintetraacetic acid (EDTA) modified Zn-Al-LDHs, and (2) [Cu(H 2 O) 6 ] 2+ release from a copper doped Mg-Al-LDHs. The results obtained are comparable to those reported in previous works using different quantification techniques. FI-AM determination is applied without sample pretreatment (solid–supernatant separation) providing a high sampling rate (above 120 samples h −1) that allows a better comprehension of the processes, particularly at the initial stages.