Determination of Total Germanium in Chinese Herbal Remedies by Square-Wave Catalytic Adsorptive Cathodic Stripping Voltammetry at an Improved Bismuth Film Electrode

Abstract

A catalytic adsorptive cathodic stripping voltammetric method on an improved bismuth film electrode (BiFE) for the determination of trace germanium in the presence of pyrogallol has been investigated. A well-defined and sensitive stripping peak of Ge(IV)-pyrogallol complex was observed at −0.79 V (versus SCE) in a 0.1 M acetate buffer solution (pH 4.8) at a deposition potential of −0.34 V. The reduction current is catalytically enhanced by adding KBrO 3 . The experimental variables and potential interference were studied. Compared with the BiFE plated in the solution prepared based on HAc-NaAc without trisodium citrate, the improved BiFE electrodeposited in the solution of HAc-NaAc containing trisodium citrate displayed a better electroanalytical performance for the determination of germanium(IV). Under the optimized conditions, the detection limit of Ge(IV) was 60 ng L −1 , and the relative standard deviation (RSD) was 3.73% at 5 g L −1 level ( = 9). This method was successfully applied to determine the total germanium in several Chinese herbal remedies.

Bismuth film electrode and chloranilic acid as a new alternative for simple, fast and sensitive Ge(iv) quantification by adsorptive stripping voltammetry

“…21 This may indicate that it is very difficult to replace the toxic mercury electrode by the more environmentally friendly mercury free electrode in compliance with requested analytical parameters. We have described a new adsorptive voltammetric strategy for trace germanium determination using the bismuth lm electrode as a working electrode and chloranilic acid as a complexing agent.…”

“…Zhong et al recommend that the bismuth lm electrode should be organized in ex situ mode, which required an additional step of applying the potential of À1.0 V for 5 min in a separate voltammetric cell and next the transfer of the three-electrode system to a new voltammetric cell containing the analyzed sample where accumulation of germanium for 150 s was performed. 21 In our procedure the in situ bismuth lm electrode was used, so the whole measurement including preparation of BiFE, germanium accumulation, and stripping was performed in one cell and proceeded in less than one minute.…”

“…Another advantage of our procedure is its insensitivity to relatively high concentrations of organic compounds, such as surface active compounds, humic compounds and natural organic matter, which disturb the voltammetric signal of germanium in other voltammetric procedures using both the bismuth lm electrode 21 and the mercury electrode. …”

“…A breakthrough in this eld was the year 2000 when the bismuth lm electrode was introduced by Wang's team. [21][22][23] In the following years numerous analytical applications of this electrode were described in the literature for trace determinations of different metals, such as As(III), Cd(II), Co(II), Cr(VI), Fe(III), Ga(III), In(III), Ni(II), Pb(II), Sb(III), Ti(IV), Tl(I).…”

Визначення Олова Та Германію З Нонілфлуороном І Полімерними Флокулянтами В Рослинних Матеріалах

“…Германий(IV) определяют атомно-эмиссионной спектроскопией с индуктивно-связанной плазмой (АЭС-ИСП) [4], атомно-абсорбционным методом с электро-термической атомизацией пробы (ААС-ЭТА), который требует предварительного концентрирования [5; 6], вольтамперо-метрически (0.06 мкг/дм 3 ) [7]. Более доступными являются спектрофото-метрические методики определения Ge(IV) с триоксифлуоронами (ТОФ) (предел определения колеблется от 0.1 нг/мл до 0.04 мкг/мл в зависимости от условий определения и типа ТОФ) [8][9][10].…”