Electrocatalytic oxidation and flow detection of hydrazine compounds in liquid chromatography at a vitamin B‐12 adsorbed glassy carbon electrode

Abstract

A vitamin B-12 chemically modfied electrode (CME) was constructed by adsorption of vitamin B-12 onto a glassy carbon surface. The electrode catalyzes the electrooxidation of hydrazine compounds over a wide pH range. The electrocatalytic behavior of hydrazines is elucidated with respect to the CME preparation conditions, solution pH, operating potential, mobile phase flow rate, and other variables. When applied to liquid chromatographic detection of the analytes, the vitamin B-12 CME yielded a linear response range over 2 orders of magnitude, and detection limits at the picomole level, The vitamin B-12 CME offers acceptable catalytic stability in both batch and flow systems.

DNA Biosensor Based on Self-Assembled Bilayer Lipid Membranes for the Detection of Hydrazines

“…The oligonucleotides used were 5 0 -hexadecyl-deoxythymidylic acid icosanucleotide (dT 20 -C 16 ) and deoxyadenylic acid icosanucleotide (dA 20 ), and were synthesized as previously reported [2][3][4]20]. The concentrations of the oligonucleotides in normal saline that were used to treat s-BLMs were 124.4 g/mL and 62.4 g/mL, respectively.…”

“…Figures 3A and B show results with two different concentrations of dT 20 -C 16 . Larger concentrations of the oligomer (i.e., more than 24.9 ng/mL) resulted in substantially increased background ion current, and limited the useful range of the analytical signals.…”

“…The increased sensitivity of response of BLMs to hydrazine when ssDNA is present (by 10 000 fold) suggests that the effects of hydrazine are linked to the presence of more cations at the BLM surface in the presence of ssDNA. The difference of response of BLMs to hydrazine in the presence of dT 20 -C 16 and dA 20 is likely due to the issues associated with partition coefficients (larger for dT 20 -C 16 ) and different orientations of immobilized ssDNA due to steric hinderance (C 16 chain limits degrees of freedom). This latter consideration of orientation is significant when considering charge screening due to double layer thickness [18].…”

“…The miniaturization that can be achieved when using electrochemical probes, and the portability of associated instrumentation, make such probes very attractive for the on-site monitoring of hydrazine compounds. Various chemically modified electrodes based on different electrocatalytic moieties have been developed for the detection of hydrazines [13][14][15][16], and analogous biosensing schemes for measurement of hydrazines have been developed [12,17].…”

Determination of isoniazid and hydrazine by capillary electrophoresis with amperometric detection at a Pt‐particle modified carbon fiber microelectrode

“…Previous efforts for enhancing the amperometric detection of hydrazine included the application of a preanodized glassy carbon electrode13 and the use of various chemically modified electrodes (CMEs) which can offer a promising way to minimize the overpotential effects.14-18 These methods have been constructed and applied in liquid chromatography/electrochemistry (LCEC). [13][14][15][16][17][18] Numerous CMEs have been used for both flow injection analysis and liquid chromatography system. Few reports using CMEs in capillary electrophoresis as electrochemical detection (CEEC) appeared even though CEEC has attracted increasing attention.lg Col6n and his co-workers2' have tried two types of copper modified carbon fiber electrodes.…”