A cutting-edge electrochemical sensing platform for the simultaneous determination of the residues of antimicrobial drugs, rifampicin and norfloxacin, in water samples.

BACKGROUND: The widespread use and abuse of antibiotics has resulted in the pollution of water sources with antibiotic residues, posing a threat to human health, the environment, and the economy. Therefore, a highly sensitive and selective method is required for their detection in water samples. Herein, advanced ultrasensitive electrochemical sensor platform was developed by integrating gold-silver alloy nanocoral clusters (Au-Ag-ANCCs) with functionalized multi-walled carbon nanotube-carbon paste electrode (f-MWCNT-CPE) and choline chloride (ChCl) nanocomposites for simultaneously determining the residues of antimicrobial drugs, rifampicin (RAMP) and norfloxacin (NFX), in water samples. RESULTS: The developed sensor (Au-Ag-ANCCs/f-MWCNTs-CPE/ChCl) was extensively characterized using several analytical (UV-Vis, FT-IR, XRD, SEM, and EDX) and electrochemical (EIS, CV, and SWV) techniques. It exhibited outstanding performance in a wide linear range, from 14 pM to 115 µM for RAMP, and from 0.9 nM to 200 µM for NFX, with a limit of detection (LOD, 3σ/m, S/N = 3, n = 5) and a limit of quantification (LOQ, 10σ/m, S/N = 3, n = 5) values of 2.7 pM and 8.85 pM for RAMP, and 0.14 nM and 0.47 nM for NFX, respectively. The sensor also exhibited exceptional reproducibility, stability, and resistance to interference. SIGNIFICANCE: The developed sensor was effectively utilized to determine RAMP and NFX residues in hospital wastewater, river, and tap water samples, yielding recoveries within the range of 96.8-103 % and relative standard deviations below 5 %. Generally, the proposed sensor demonstrated remarkable performance in detecting the target analytes, making it an ideal tool and the first of its kind for addressing global antibiotic residue pollutants in water sources.

Adsorption of hexavalent chromium using Water Hyacinth Leaf Protein Concentrate/Graphene Oxide hydrogel.

Water Hyacinth Leaf Protein Concentrate/Graphene Oxide (WHLPC/GO) hydrogel was synthesized for the removal of Cr(VI) from wastewater. About 90% of the prepared hydrogel constitutes WHLPC. The prepared material was characterized by FT-IR and XRD. The process variables such as pH, contact time, adsorbent dosage, initial Cr(VI) concentration, and temperature were optimized using a batch mode experiment. Kinetic studies were also conducted and it was observed that the chemosorptive pseudo-second-order best described the adsorption system with a correlation coefficient (R2) of 0.984. The highest adsorption capacity of 322.00 mg/g was achieved at pH 1.0, and equilibrium was achieved within 420 min. Various isotherm models were analyzed using non-linear fitting. It was found that the Sips model provides the best fit, indicating heterogeneous and uniform active site surface adsorption of Cr(VI) on the WHLPC/GO. The reuse efficiency of the synthesized material was also found to be greater than 84% for five consecutive cycles. Thermodynamic studies were conducted and results revealed that the adsorption was spontaneous and endothermic.