Spectroelectrochemistry of the quasi-reversible reduction and oxidation of hemoglobin at a methylene blue adsorbed modified electrode

1988 ◽  
Vol 19 (2) ◽  
pp. 337-346 ◽  
Author(s):  
Shihua Song ◽  
Shaojun Dong
Keyword(s):  
Methylene Blue ◽  
Modified Electrode ◽  
Reduction And Oxidation ◽  
Reversible Reduction

scholarly journals Simultaneous Determination of Uric Acid and Xanthine Using a Poly(Methylene Blue) and Electrochemically Reduced Graphene Oxide Composite Film Modified Electrode

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Gen Liu ◽  
Wei Ma ◽  
Yan Luo ◽  
Deng-ming Sun ◽  
Shuang Shao
Keyword(s):  
Methylene Blue ◽  
Uric Acid ◽  
Graphene Oxide ◽  
Composite Film ◽  
Simultaneous Determination ◽  
Reduced Graphene Oxide ◽  
Modified Electrode ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide

Poly(methylene blue) and electrochemically reduced graphene oxide composite film modified electrode (PMB-ERGO/GCE) was successfully fabricated by electropolymerization and was used for simultaneous determination of uric acid (UA) and xanthine (Xa). Based on the excellent electrocatalytic activity of PMB-ERGO/GCE, the electrochemical behaviors of UA and Xa were studied by cyclic voltammetry (CV) and square wave voltammetry (SWV). Two anodic sensitive peaks at 0.630 V (versus Ag/AgCl) for UA and 1.006 V (versus Ag/AgCl) for Xa were given by CV in pH 3.0 phosphate buffer. The calibration curves for UA and Xa were obtained in the range of 8.00 × 10−8~4.00 × 10−4 M and 1.00 × 10−7~4.00 × 10−4 M, respectively, by SWV. The detection limits for UA and Xa were3.00×10-8 M and5.00×10-8 M, respectively. Finally, the proposed method was applied to simultaneously determine UA and Xa in human urine with good selectivity and high sensitivity.

scholarly journals Selective Determination of Dopamine in Presence of Ascorbic Acid Using Nafion Coated Methylene Blue Functionalized Graphite Electrode

2019 ◽  
Vol 31 (10) ◽  
pp. 2185-2190
Author(s):  
G. Sivasankari ◽  
K. Sivasankari ◽  
T. Nalini ◽  
P. Padmapriya ◽  
M. Nadhiya
Keyword(s):  
Methylene Blue ◽  
Ascorbic Acid ◽  
Modified Electrode ◽  
Electrode Surface ◽  
Graphite Electrode ◽  
Low Cost ◽  
Differential Pulse ◽  
Selective Determination ◽  
The Stability

An electrochemical sensor has been developed using methylene blue (MB) unctionalized graphite for the selective determination of dopamine in the presence of ascorbic acid. The immobilization of methylene blue on graphite was done by carbodiimide coupling method. The methylene blue functionalized graphite was characterized by SEM, FTIR spectroscopy and UV-visible spectroscopy. The immobilization of methylene blue functionalized graphite (MB-G) on the electrode surface was made by drop casting a small volume of MB-G dispersed methanol solution on the electrode surface. About 5 L of 0.5 % Nafion solution was also dropcasted for the stability and selectivity. The MB-G modified electrode was characterized by cyclic voltammetry. The modified electrode promotes the electrocatalytic oxidation of dopamine at a lower potential of 160 mV. The selective determination of dopamine in the presence of 100 times higher concentration of ascorbic acid was achieved by differential pulse voltammetry. The modified electrode offered a simple, selective and sensitive determination of low levels of dopamine. Also the oxidation over potential was reduced to an extent of 360 mV comparing with the bare graphite electrode. The proposed sensor has the advantage of easy fabrication, low cost, good sensitivity, reproducibility and stability.

Sensitive Determination of Rutin Using a Nafion/PMB/Graphene Composite-Modified Glassy Electrode

2013 ◽  
Vol 641-642 ◽  
pp. 566-569
Author(s):  
Feng Cai ◽  
Jian Fei Xia ◽  
Zong Hua Wang ◽  
Yan Zhi Xia ◽  
Fei Fei Zhang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Detection Limit ◽  
Modified Electrode ◽  
Linear Relation ◽  
Peak Current ◽  
Good Linear ◽  
Graphene Composite ◽  
Scan Rate ◽  
Sensitive Determination

A novel Nafion/PMB/G/GCE was prepared by firstly electro-polymerization of MB to G/GCE and then coating Nafion on PMB/G/GCE. The as-prepared modified electrode combining the advantages of Nafion, methylene blue and G was employed for the sensitive detection of rutin. The results showed that the peak current of rutin obtained on Nafion/PMB/G/GCE was obviously high compared to bare electrode and G/GCE. Under the optimized value of pH, which was pH 3.0, peak current of rutin had good linear relation with the scan rate. At the same time, peak current increased linearly with increasing concentration of rutin. The linear range was from 5×10-7 mol/L to 1.2×10-5 mol/L, and the detection limit was 9.5×10-8 mol/L

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