Poly(acridine orange)-modified glassy carbon electrodes: electrosynthesis, characterisation and sensor application with uric acid

Thermally Activated Delayed Fluorescence and Room-Temperature Phosphorescence in Materials with Imidazo-pyrazine-5,6-dicarbonitrile Acceptors

Three donor-acceptor compounds based on the imidazo-pyrazine-5,6-dicarbonitrile (IPDC) acceptor were synthesized. The IPDC emitters exhibit blue to near-infrared (NIR) emission with up to 54 % photoluminescent quantum yield. 9,9-Dimethyl-9,10-dihydroacridine (ACR), phenoxazine (POX), and phenothiazine (PTZ) served as electron donors. IPDC-POX displayed NIR emission in toluene solution, while showing room-temperature phosphorescence in the solid state. IPDC-ACR exhibited yellow thermally activated delayed fluorescence. Interestingly, dual-emissive behavior as well as excitation-dependent thermally activated delayed fluorescence (TADF) was found for IPDC-PTZ, arising from the two conformers of phenothiazine derivatives. Overall, this work describes a novel strong electron acceptor from the fusion of imidazole, pyrazine, and nitrile functional groups into one conjugated heterocycle for materials exhibiting NIR emission, TADF, and/or room-temperature phosphorescence (RTP).

Electroanalytical Analysis of Guaifenesin on Poly(Acridine Orange) Modified Glassy Carbon Electrode and its Determination in Pharmaceuticals and Serum Samples

BACKGROUND

Electroanalytical methods are very functional to detect drugs in pharmaceuticals (tablets, syrups, suppositories, creams, and ointments) and biological samples.

OBJECTIVE

This study is aimed to make selective, sensitive, simple, fast, and low cost electrochemical analysis of expectorant drug guaifenesin in pharmaceuticals and serum samples.

METHODS

Differential pulse adsorptive stripping voltammetric method for determination of guaifenesin on a poly(acridine orange) modified glassy carbon electrode has been developed. Glassy carbon electrode was modified with electropolymerization of the acridine orange monomer for the sensitive determination of guaifenesin. Guaifenesin provided highly reproducible and welldefined irreversible oxidation peaks at +1.125 V and +1.128 V (vs. Ag/AgCl) in the selected supporting electrolyte and human serum samples, respectively.

RESULTS

Under optimized conditions, linear response of peak current on the concentration of guaifenesin has been obtained in the ranges of 2.00×10-7 to 1.00×10-4 M in Britton Robinson buffer solution at pH 7.0 and 4.00×10-7 to 1.00×10-4 M in serum samples. The precision of the method was detected by intraday and inter-day repeatability studies in the supporting electrolyte and serum samples media.

CONCLUSION

The analytical applicability of the proposed method exhibited satisfying determination results for guaifenesin from pharmaceutical dosage forms (syrup) and human serum samples without any pre-separation procedures.

Sensitive Detection of Levocetirizine as a new Generation Antihistamine by Stripping Square Wave Voltammetry

Background::

new and selective electrochemical sensor was developed for the determination of levocetirizine dihydrochloride, which is an antihistaminic drug.

Method::

The investigation was performed by using cyclic, differential pulse and square wave voltammetric methods on the β-cyclodextrin modified glassy carbon electrode. It is thereby planned to obtain information about levocetirizine determination and its mechanism.

Result::

The efficiency of experimental parameters including pH, scan rate, and accumulation potential and time on the anodic response of levocetirizine dihydrochloride was studied. By employing the developed method and under optimized conditions, the current showed linear dependence with a concentration in the range between 2 × 10-8 M and 6 × 10-6 M in pH 2.0 Britton Robinson (BR) buffer.

Conclusion::

The achieved limits of detection and quantification were found as 3.73 × 10-10 M and 1.24 × 10-9 M, respectively. In addition, the possibility of applying the developed sensor for real sample analysis was investigated, so β-cyclodextrin modified glassy carbon electrode was used to determine levocetirizine dihydrochloride in Xyzal® tablet dosage form. Finally, this sensor was successfully applied to the real sample as a selective, simple, reproducible, repeatable electrochemical sensor.