کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10560638 | 969739 | 2005 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Unprecedented stable aqueous semiquinone methide radical formation interferes with adsorptive cathodic stripping voltammetry of cobalt methyl thymol blue
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
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چکیده انگلیسی
A putatively highly sensitive and selective method for the determination of cobalt in aqueous samples by catalytic adsorptive cathodic stripping voltammetry using methyl thymol blue (MTB) as the ligand has been documented [A. Safavi, E. Shams, Talanta 51 (2000) 1117] and its underlying mechanism has been briefly explored [A. Safavi, E. Shams, Electroanalysis 14 (2002) 708]. In an attempt to adapt the method for application in metalloprotein analysis we obtained erratic results, which were traced down to the redox non-innocence of the free ligand in the potential range prescribed for the metal analysis. On the hanging mercury drop electrode free methyl thymol blue is reversibly one-electron reduced to the semiquinone form with Em,7.0 = â482 mV versus NHE at 22 °C, and the radical is subsequently quasi-reversibly one-electron reduced to the quinol form with Em,7 â â0.9 V. This observation invalidates the use of MTB in electrochemical analysis of metal ions. This is also the first observation ever of a stable quinone methide radical in aqueous solution.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Talanta - Volume 67, Issue 3, 15 September 2005, Pages 597-602
Journal: Talanta - Volume 67, Issue 3, 15 September 2005, Pages 597-602
نویسندگان
Alidin N. Niztayev, Wilfred R. Hagen,