title: Potentiometric flow injection system for determination of reductants using a polymeric membrane permanganate ion-selective electrode based on current-controlled reagent delivery.
abstract: A polymeric membrane permanganate-selective electrode has been developed as a current-controlled reagent release system for potentiometric detection of reductants in flow injection analysis. By applying an external current, diffusion of permanganate ions across the polymeric membrane can be controlled precisely. The permanganate ions released at the sample-membrane interface from the inner filling solution of the electrode are consumed by reaction with a reductant in the sample solution thus changing the measured membrane potential, by which the reductant can be sensed potentiometrically. Ascorbate, dopamine and norepinephrine have been employed as the model reductants. Under the optimized conditions, the potential peak heights are proportional to the reductant concentrations in the ranges of 1.0×10(-5) to 2.5×10(-7)M for ascorbate, of 1.0×10(-5) to 5.0×10(-7)M for dopamine, and of 1.0×10(-5) to 5.0×10(-7)M for norepinephrine, respectively with the corresponding detection limits of 7.8×10(-8), 1.0×10(-7) and 1.0×10(-7)M. The proposed system has been successfully applied to the determination of reductants in pharmaceutical preparations and vegetables, and the results agree well with those of iodimetric analysis.
authors: CAS and Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, PR China.
authors: Wenjing
authors: W
authors: Song
authors: Jiawang
authors: J
authors: Ding
authors: Rongning
authors: R
authors: Liang
authors: Wei
authors: W
authors: Qin
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis; D004298:Dopamine / Q000032:analysis; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D017022:Flow Injection Analysis / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D017736:Ion-Selective Electrodes; D017895:Manganese Compounds / Q000737:chemistry; D008567:Membranes, Artificial; D009638:Norepinephrine / Q000032:analysis; D010087:Oxides / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011199:Potentiometry / Q000295:instrumentation / Q000379:methods*; D019163:Reducing Agents / Q000032:analysis*; D012996:Solutions; D014675:Vegetables / Q000737:chemistry*
chemical_list: D017895:Manganese Compounds; D008567:Membranes, Artificial; D010087:Oxides; D004364:Pharmaceutical Preparations; D019163:Reducing Agents; D012996:Solutions; C048856:permanganic acid; D001205:Ascorbic Acid; D004298:Dopamine; D009638:Norepinephrine