Exploitation of o-benzoyl benzoic acid as an efficient electroactive material for selective determination of Cr (III) ions in pharmaceutical samples and industrial waste water using carbon sensor.

Herein, for the first time, o-benzoyl benzoic acid has been explored as a promising electroactive material for the fabrication of sensitive, precise and accurate carbon paste electrode (CPE) for selective detection of Cr (III) ion. o-benzoyl benzoic acid (o-BBA) as a sensing material and tricresylphosphate (TCP) as a solvent mediator improved the developed sensor performance to get the Nernstian cationic slope of 20.03 ± 0.11 mV decade-1 within the concentration range of 5.0 × 10-7-1.0 × 10-1 mol L-1. The sensor displayed a fast response time of 12 s reflecting a pH independency over the pH range of 3.1-4.7. Moreover, the reaction between the sensing material and Cr (III) ion on the developed sensor surface was elucidated using the microscopic technique such as scanning electron microscope (SEM) in addition to the energy dispersive X-ray analyzer (EDX). The proposed sensor showed an adequate shelf lifetime (∼33 days). The values of potentiometric selectivity coefficient were obtained by fixed interference and separate solution methods affirming a high distinguishing power of the fabricated sensor toward Cr (III) ions over the other interfering ions. The established sensor could be utilized with a promising success for the Cr (III) ion estimation in the industrial waste water and in the pharmaceutical forms. Additionally, it has been employed as a promising indicator sensor with a superior performance for potentiometric titration of Cr (III) ion against EDTA.

Application of carbon sensors for potentiometric determination of copper(II) in water and biological fluids of Wilson disease patients. Studying the surface reaction using SEM, EDX, IR and DFT.

The performance characteristics of a new selective and sensitive modified screen printed electrode (MSPE; electrode I) and carbon paste electrode (MCPE; electrode II) based on 2-N, N-dimethylcarbamimidoyl (metformin) as modifier for the potentiometric determination of copper (II) in water sample, serum and urine samples of Wilson disease patients have been optimized. The chemical reaction which happens between Cu (II) and the modifier on the surface of the sensors was investigated with scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX), IR spectra measurement and computational calculations at DFT/B3LYP. The sensors showed perfect potentiometric response for Cu (II) over concentration range of 1.0 × 10-6 - 1.0 × 10-2 and 1.0 × 10-6 - 5.0 × 10-2 mol L-1 with a detection limit of 1.0 × 10-6 mol L-1with divalent slope value 30.2 and 31.8 mV decade-1 over the pH range of 2-6 for MCPE and MSPE, respectively. MSPE was stable with repeatable potential over period of 37 days and exhibits fast response time of 6 and 10 s for MSPE and MCPE, respectively. Also, these sensors exhibited good selectivity towards Cu(II) with respect to other metal ions and have higher antibacterial activity against Staphylococcus aureus as Gram-positive bacteria and Escherichia coli as Gram-negative bacteria. The obtained results using the sensors were in agreement with those obtained using the reported method.