Determination of Dihydroxybenzene Isomers in Wastewater Samples at Poly(Glutamic Acid) Modified Glassy Carbon Electrode

2014 ◽  
Vol 675-677 ◽  
pp. 284-287 ◽  
Author(s):  
Chun Yan Wang ◽  
Ying Xin Qi ◽  
Xiao Qiu Liu

A simple electrochemical method has been developed for the simultaneous determination of dihydroxybenzene isomers in wastewater samples with poly (glutamic acid) modified electrode (PGA/GCE). PGA/GCE was fabricated by electropolymerization of glutamic acid on a glassy carbon electrode (GCE) through cyclic voltammetry (CV). PGA/GCE showed an excellent electrocatalytic ability towards the oxidation of hydroquinone (HQ) and catechol (CC). With CV and differential pulse votammetric (DPV) measurements, HQ and CC in wastewater samples could be simultaneously analyzed at PGA/GCE. The linear range for HQ and CC were 5 - 100 μM and 2 - 160 μM, with a detection limit of 2.0 μM and 1.0 μM, respectively. Moreover, PGA/GCE exhibited good selectivity and repeatability. The method has a promising application in the monitoring of HQ and CC of wastewater.

2007 ◽  
Vol 72 (9) ◽  
pp. 1177-1188 ◽  
Author(s):  
Xinhua Lin ◽  
Wei Li ◽  
Hong Yao ◽  
Yuanyuan Sun ◽  
Liying Huang ◽  
...  

A poly(Eriochrome Black T) chemically modified glassy carbon electrode modified with Eriochrome Black T was prepared by cyclic voltammetry. The modified electrode showed an excellent electrocatalytic activity in oxidation of noradrenaline (NA) and could separate its electrochemical responses from those of L-ascorbic acid (AA) and uric acid (UA). Differences of the oxidation peak potentials for NA-AA and UA-NA were about 150 mV. The responses to NA, AA and UA of the modified electrode are relatively independent. Using differential pulse voltammetry, the peak currents of NA at modified glassy carbon electrode increased linearly with the concentration of NA from 0.5 to 100 μmol l-1. The detection limit was 0.2 μmol l-1. With the modified electrode, UA could be selectively determined in the presence of AA. The method showing a wide linear dynamic range and excellent sensitivity was successfully applied to the determination of NA in pharmaceutical injections and various samples.


2014 ◽  
Vol 92 (4) ◽  
pp. 329-336 ◽  
Author(s):  
Mahmoud Mohamed Kamel ◽  
Ehab Mahmoud Abdalla ◽  
Mohamed Sayed Ibrahim ◽  
Yassin Mohamed Temerk

The electrochemical behavior of ascorbic acid (AA), dopamine (DA), and uric acid (UA) on a dl-norvaline-modified glassy carbon electrode (GCE) was studied by cyclic voltammetry. The bare GCE failed to distinguish the oxidation peaks of AA, DA, and UA in phosphate-buffered solution (pH 5.0), while the dl-norvaline-modified GCE could separate them efficiently. In differential pulse voltammetric (DPV) measurements, the modified electrode resolved the overlapped voltammetric responses of AA, DA, and UA into three well-defined voltammetric peaks. Under optimum conditions, the anodic peak currents of DPV for AA, DA, and UA were proportional to the concentration in the range of 20–400, 1–40, and 15–180 μmol/L, respectively, with a correlation coefficient (r) of around 0.998. The detection limits were 5, 0.3, and 10 μmol/L (S/N = 3) for AA, DA, and UA, respectively. Satisfactory results were achieved for the determination of AA in vitamin C tablets, DA in a dopamine ampoule sample, and UA in human blood serum samples.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1708 ◽  
Author(s):  
Aftab Aslam Parwaz Khan

A novel nanocomposite of cellulose based on multiwalled carbon nanotube (MWCNT) was synthesized by a simple solution mixing–evaporation method. The morphology, thermal investigations, electrocatalytic oxidation of amitriptyline were analyzed at multi-walled carbon/cellulose nanocomposite in detail. The amitriptyline (AMT) drug was electrochemically studied in a phosphate buffer at different pH using the MWCNT/cellulose modified glassy carbon electrode (GCE). As per the linear relationship among AMT along with peak current, differential pulse voltammetry technique has been established for their quantitative pharmaceutical’s determination. The oxidation potential shifted negatively compared to GCE, showing that the MWCNT/cellulose modified electrode had an excellent catalytic activity for the AMT oxidation. The anodic peak current varied linear response with AMT’s concentration in the range of 0.5 to 20.0 μM with a LOD of 0.0845 μM and LOQ of 0.282 μM, respectively. The proposed method was effectively put on the determination of AMT in pharmaceutical and urine samples. This novel methodology is presented here as an example of a complete development methodology for the determination of amitriptyline drug and sensor for use in healthcare fields.


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Sevgi Güney ◽  
Gülcemal Yıldız ◽  
Gönül Yapar

A new voltammetric sensor based on an aryl amide type podand, 1,8-bis(o-amidophenoxy)-3,6-dioxaoctane, (AAP) modified glassy carbon electrode, was described for the determination of trace level of mercury (II) ion by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). A well-defined anodic peak corresponding to the oxidation of mercury on proposed electrode was obtained at 0.2 V versus Ag/AgCl reference electrode. The effect of experimental parameters on differential voltammetric peak currents was investigated in acetate buffer solution of pH 7.0 containing 1 × 10−1 mol L−1NaCl. Mercury (II) ion was preconcentrated at the modified electrode by forming complex with AAP under proper conditions and then reduced on the surface of the electrode. Interferences of Cu2+, Pb2+, Fe3+, Cd2+, and Zn2+ions were also studied at two different concentration ratios with respect to mercury (II) ions. The modified electrode was applied to the determination of mercury (II) ions in seawater sample.


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