Premium
The Electrochemical Behavior of α‐Ketoglutarate at the Hanging Mercury Drop Electrode in Acidic Aqueous Solution and Its Practical Application in Environmental and Biological Samples
Author(s) -
Yang Li,
Yang Zhengbiao,
Zhang Min,
Ni Haiyan,
Ji Ming,
Tang Yongzheng,
Yang Xiaodi,
Long Xiufen,
Bi Shuping
Publication year - 2004
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200302913
Subject(s) - hanging mercury drop electrode , detection limit , chemistry , buffer solution , aqueous solution , drop (telecommunication) , dropping mercury electrode , analytical chemistry (journal) , electrode , voltammetry , electrochemistry , mercury (programming language) , adsorption , relative standard deviation , linear range , chromatography , telecommunications , computer science , programming language
The voltammetric behavior of α‐ketoglutarate (α‐KG) at the hanging mercury drop electrode (HMDE) has been investigated in acetate buffer solution. Under the optimum experimental conditions (pH 4.5, 0.2 M NaAc‐HAc buffer solution), a sensitive reductive wave of α‐KG was obtained by linear scan voltammetry (LSV) and the peak potential was −1.18 V (vs. SCE), which was an irreversible adsorption wave. The kinetic parameters of the electrode process were α =0.3 and k s =0.72 1/s. There was a linear relationship between peak current i p, α‐KG and α‐KG concentration in the range of 2×10 −6 –8×10 −4 M α‐KG. The detection limit was 8×10 −7 M and the relative standard deviation was 2.0% ( C α‐KG =8×10 −4 M, n =10). Applications of the reductive wave of α‐KG for practical analysis were addressed as follows: (1) It can be used for the quantitative analysis of α‐KG in biological samples and the results agree well with those obtained from the established ultraviolet spectrophotometric method. (2) Utilizing the complexing effect between α‐KG and aluminum, a linear relationship holds between the decrease of peak current of α‐KG Δ i p and the added Al concentration C Al IIIin the range of 5.0×10 −6 –2.5×10 −4 M. The detection limit was 2.2×10 −6 M and the relative standard deviation was 3.1% ( C Al III=4×10 −5 M, n =10). It was successfully applied to the detection of aluminum in water and synthetic biological samples with satisfactory results, which were consistent with those of ICP‐AES. (3) It was also applied to study the effect of Al III on the glutamate dehydrogenase (GDH) activity in the catalytically reaction of α‐KG+NH $\rm{ {_{4}^{+}}}$ +NADH⇌ L ‐glutamate+NAD + +H 2 O by differential pulse polarography (DPP) technique. By monitoring DPP reductive currents of NAD + and α‐KG, an elementary important result was found that Al could greatly affect the activity of GDH. This study could be attributed to intrinsic understanding of the aluminum's toxicity in enzyme reaction processes.