Amperometric flow injection analysis as a new approach for studying disperse systems

作者：Erro Eustaquio M; Giacomelli Carla E; Rosario Perez M; Angeles Ulibarri M; Ortiz Patricia I; Rojas Ricardo^*

来源：Electrochimica Acta, 2009, 55(2): 475-479.

DOI：10.1016/j.electacta.2009.08.053

• Dispersed systems
• Flow injection
• Amperometry
• Copper quantification
• Layered double hydroxides

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 amperometric 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 (-0.25V vs Ag/AgCl/NaCl (3 mol L(-1))), presents a linear relationship with [Cu(H(2)O)(6)](2 ) concentration and the procedure offers high sensitivity (slope = 0.036 mu A/(mu mol L(-1))), a low detection limit (=0.7 mu mol L(-1)) and a wide quantification range (4-200 mu 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.

• 出版日期2009-12-30