Static and dynamic analysis of sulfamethoxazole using GO/ZnO modified glassy carbon electrode by differential pulse voltammetry and amperometry techniques

A promising electrochemical sensor based on PVP-induced shape control of a hydrothermally synthesized layered structured vanadium disulfide for the sensitive detection of a sulfamethoxazole antibiotic

The presence of sulfamethoxazole (SMX) in natural waters has become a significant concern recently because of its detrimental effects on human health and the ecological environment. To address this issue, it is of utmost urgency to develop a reliable method that can determine SMX at ultra-low levels. In our research, we utilized PVP-induced shape control of a hydrothermal synthesis method to fabricate layer-like structured VS2, and employed it as an electrode modification material to prepare an electrochemical sensor for the sensitive determination of SMX. Thus, our prepared VS2 electrodes exhibited a linear range of 0.06-10.0 μM and a limit of detection (LOD) as low as 47.0 nM (S/N = 3) towards SMX detection. Additionally, the electrochemical sensor presented good agreement with the HPLC method, and afforded perfect recovery results (97.4-106.8%) in the practical analysis. The results validated the detection accuracy of VS2 electrodes, and demonstrated their successful applicability toward the sensitive determination of SMX in natural waters. In conclusion, this research provides a promising approach for the development of electrochemical sensors based on VS2 composite materials.

A selective analysis of sulfamethoxazole - Trimethoprim in tablet formulations using graphene oxide-zinc oxide quantum dots based nanocomposite modified glassy carbon electrode

In this study, simultaneous analysis on electrochemical detection of SMX and TMP in tablet formulation has been made using graphene oxide (GO) and ZnO QDs (GO-ZnO QDs) based nanocomposite modified glassy carbon electrode (GCE). The functional group presence was observed using FTIR study. The electrochemical characterization for GO, ZnO QDs and GO-ZnO QDs was studied using cyclic voltammetry using [Fe(CN)₆]^3- medium. In order to estimate the electrochemical redox behavior of SMX and TMP from tablet, the developed electrodes GO/GCE, ZnO QDs/GCE and GO-ZnO QDs/GCE are initially tested for electrochemical activity towards the SMX tablet in BR pH 7 medium. Later their electrochemical sensing has been monitored using square wave voltammetry (SWV). On observing the characteristic behavior of developed electrodes, GO/GCE exhibited detection potential of +0.48 V for SMX and +1.37 V for TMP whereas, ZnO QDs/GCE with +0.78V for SMX and for TMP 1.01 V respectively. Similarly, for GO-ZnO QDs/GCE, its 0.45 V for SMX and 1.11 V for TMP are observed using cyclic voltammetry. The obtained potential results on detecting SMX and TMP are in good agreement with previous results. Under optimized conditions, the response has been monitored with linear concentration range 50 μg/L to 300 μg/L for GO/GCE, ZnO QDs/GCE and GO-ZnO QDs/GCE in SMX tablet formulations. Their detection limits for the individual detection using GO-ZnO/GCE for SMX and TMP are found to be 0.252 ng/L and 19.10 μg/L and for GO/GCE it was 0.252 pg/L and 2.059 ng/L respectively. It was observed that ZnO QDs/GCE could not provide the electrochemical sensing towards SMX and TMP which may be due to the ZnO QPs can act as a blocking layer impeding the electron transfer process. Thus, the sensor performance lead to promising biomedical applications in real-time monitoring on evaluating selective analysis with SMX and TMP in tablet formulations.

Multisensory Systems Based on Perfluorosulfonic Acid Membranes Modified with Polyaniline and PEDOT for Multicomponent Analysis of Sulfacetamide Pharmaceuticals

The degradation of sulfacetamide with the formation of sulfanilamide leads to a deterioration in the quality of pharmaceuticals. In this work, potentiometric sensors for the simultaneous determination of sulfanilamide, sulfacetamide and inorganic ions, and for assessing the degradation of pharmaceuticals were developed. A multisensory approach was used for this purpose. The sensor cross-sensitivity to related analytes was achieved using perfluorosulfonic acid membranes with poly(3,4-ethylenedioxythiophene) or polyaniline as dopants. The composite membranes were prepared by oxidative polymerization and characterized using FTIR and UV-Vis spectroscopy, and SEM. The influence of the preparation procedure and the dopant concentration on the membrane hydrophilicity, ion-exchange capacity, water uptake, and transport properties was investigated. The characteristics of the potentiometric sensors in aqueous solutions containing sulfanilamide, sulfacetamide and alkali metals ions in a wide pH range were established. The introduction of proton-acceptor groups and π-conjugated moieties into the perfluorosulfonic acid membranes increased the sensor sensitivity to organic analytes. The relative errors of sulfacetamide and sulfanilamide determination in the UV-degraded eye drops were 1.2 to 1.4 and 1.7 to 4%, respectively, at relative standard deviation of 6 to 9%.