Mechanism of electrochemical oxidation of trimethoprim at pyrolytic graphite electrode

Goyal, Rajendra N.; Kumar, Anoop

doi:10.1002/elan.1140020707

Cited by 4 publications

(7 citation statements)

References 16 publications

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“…TMP was electro‐oxidized in the pH range 3–10 to mononitroso derivative by 4e mechanism. The mononitroso derivative underwent electro‐oxidation to dinitroso derivative by 4e mechanism at pH less than 3 32. Based on our experimental observation of the involvement of 4e and on the previous report of identification of products of electro‐oxidation of TMP, we propose a possible mechanism for it (Figure 5).…”

Section: Resultssupporting

confidence: 65%

“…The amino group at position 4 of the pyrimidine ring may be more easily oxidized than the one at position 2 which is a part of stable pyrimidine system. Again, a 4e oxidation of the mononitroso derivative can lead to the formation of dinitroso derivative 32. But then, there should be two distinct peaks in the voltammogram corresponding to the formation of mono and dinitroso derivatives.…”

Section: Resultsmentioning

confidence: 99%

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Electroanalysis of trimethoprim on metalloporphyrin incorporated glassy carbon electrode

Rajith

Kumar

2010

Drug Testing and Analysis

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Trimethoprim (TMP) is a bacteriostatic antibiotic mainly used in the prophylaxis and treatment of urinary tract infections. It belongs to the class of chemotherapeutic agents known as dihydrofolate reductase inhibitors. Its use is associated with idiosyncratic reactions, including liver toxicity and agranulocytosis. In order to determine TMP electrochemically, a metalloporphyrin modified glassy carbon electrode was prepared by coating [5,10,15,20- tetrakis(4-methoxyphenyl) porphyrinato]Mn (III)chloride (TMOPPMn(III)Cl) solution on the surface of the electrode. The electrochemical behaviour of TMP in Phosphate buffer solution (PBS) on TMOPPMn(III)Cl modified glassy carbon electrode (TMOPPMn(III)Cl/GCE) was explored using differential pulse voltammetry (DPV). The voltammograms showed enhanced oxidation response at the TMOPPMn (III)Cl/GCE with respect to the bare GCE for TMP, attributable to the electrocatalytic activity of TMOPPMn(III)Cl. Electrochemical parameters of the oxidation of TMP on the modified electrode were analyzed. The electro-oxidation of TMP was found to be irreversible, pH dependent and adsorption controlled on the modified electrode. It is found that the oxidation peak current is proportional to the concentration of TMP over the range 6 × 10⁻⁸ - 1 × 10⁻⁶ M with a very low detection limit of 3 × 10⁻⁹ M at 2 min open circuit accumulation. The repeatability expressed as relative standard deviation (RSD) for n = 9 was 3.2% and the operational stability was found to be 20 days. Another striking feature is that equimolar concentration of sulfamethoxazole did not interfere in the determination of TMP. Applicability to assay the drug in urine and tablet samples has also been studied.

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Section: Resultssupporting

confidence: 65%

Section: Resultsmentioning

confidence: 99%

Electroanalysis of trimethoprim on metalloporphyrin incorporated glassy carbon electrode

Rajith

Kumar

2010

Drug Testing and Analysis

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“…Preliminary experimental studies were performed in order to understand the electrochemical behaviour of trimethoprim drug using an unmodified CPS. A simple CV measurement showed a peak at around +1.2 V, indicating oxidation of the drug ( Figure 2 ) with irreversible nature, in accordance with other studies [ 25 , 35 , 39 ].…”

Section: Resultssupporting

confidence: 91%

Carbon Fiber Paper Sensor for Determination of Trimethoprim Antibiotic in Fish Samples

Torrinha

Tavares

Dibo

et al. 2023

Sensors

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The increase in anthropogenic pollution raises serious concerns regarding contamination of water bodies and aquatic species with potential implications on human health. Pharmaceutical compounds are a type of contaminants of emerging concern that are increasingly consumed and, thus, being frequently found in the aquatic environment. In this sense, an electrochemical sensor based on an unmodified and untreated carbon fiber paper (CPS—carbon paper sensor) was simply employed for the analysis of trimethoprim antibiotic in fish samples. First, the analytical conditions were thoroughly optimized in order for the CPS to achieve maximum performance in trimethoprim determination. Therefore, an electrolyte (0.1 M Britton–Robinson buffer) pH of 7 was selected and for square wave voltammetry parameters, optimum values of amplitude, frequency and step potential corresponded to 0.02 V, 50 Hz, and 0.015 V, respectively, whereas the deposition of analyte occurred at +0.7 V for 60 s. In these optimum conditions, the obtained liner range (0.05 to 2 µM), sensitivity (48.8 µA µM−1 cm−2), and LOD (0.065 µM) competes favorably with the commonly used GCE-based sensors or BDD electrodes that employ nanostructuration or are more expensive. The CPS was then applied for trimethoprim determination in fish samples after employing a solid phase extraction procedure based on QuEChERS salts, resulting in recoveries of 105.9 ± 1.8% by the standard addition method.

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“…The voltammetric behavior of trimethoprim investigated at the [5,10,15,20-tetrakis(4-methoxyphenyl)porphyrinato]Mn(III)chloride-modified glassy carbon electrode (TMOPPMn(III)Cl/GCE) showed that TMOPPMn(III)Cl acts as an electrocatalyst for the oxidation of trimethoprim . There are two amino groups, one at position 4 of the pyrimidine ring and the other at position 2 of the stable pyrimidine system . Deprotonation of the NH 2 group attached to either C4 or C2 of trimethoprim can occur, and thus both of these possibilities were investigated computationally.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, for further calculations, we have considered the removal of a proton from the C4 amino group. The detailed mechanism − is outlined in Scheme . The first step involved in the conversion of trimethoprim (I) to nitroso derivative (IX) is the deprotonation of the NH 2 group at the fourth position to give the trimethoprim anion (II).…”

Section: Resultsmentioning

confidence: 99%

Mechanistic Study for the Facile Oxidation of Trimethoprim on a Manganese Porphyrin Incorporated Glassy Carbon Electrode

et al. 2011

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The electrocatalysis of [5,10,15,20-tetrakis(4-methoxyphenyl)porphyrinato]Mn(III)chloride (TMOPPMn(III)Cl) toward the oxidation of trimethoprim was investigated by electrochemical and computational methods. Voltammetric analysis demonstrates the ability of TMOPPMn(III)Cl to act as an electrocatalyst for the oxidation of trimethoprim. DFT calculations were performed at the B3LYP level to detect the site of oxidation as well as to survey the role of manganese porphyrin in the facile oxidation of trimethoprim. Quantum chemical calculations affirm that the deprotonation of NH2 attached to C4 is more energetically favorable as compared to deprotonation of the C2 amino group. Also, the deprotonation of trimethoprim in the TMOPPMn(III)Cl-catalyzed reaction results in the formation of a more stable anion as compared to the uncatalyzed reaction. Atoms in molecule (AIM) analysis and natural bond orbital (NBO) analysis also substantiate the utility of TMOPPMn(III)Cl in trimethoprim oxidation by confirming the coordination of trimethoprim to manganese porphyrin on removal of proton.

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Mechanism of electrochemical oxidation of trimethoprim at pyrolytic graphite electrode

Cited by 4 publications

References 16 publications

Electroanalysis of trimethoprim on metalloporphyrin incorporated glassy carbon electrode

Electroanalysis of trimethoprim on metalloporphyrin incorporated glassy carbon electrode

Carbon Fiber Paper Sensor for Determination of Trimethoprim Antibiotic in Fish Samples

Mechanistic Study for the Facile Oxidation of Trimethoprim on a Manganese Porphyrin Incorporated Glassy Carbon Electrode

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