No abstract

In this paper, we have reported an electrochemical detection of metal ions based on Calixarene-based sensor. In the sensing strategy, 3-aminopropylsilane (APTMS) was initially self-assembled on indium tin oxide (ITO) followed by functionalization of dicarboethoxycalix [4]arene (EtC4). The morphology and properties of electrodes were characterized by contact angle, atomic force microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. The electrochemical response characteristics of the modified electrodes (EtC4/APTMS/ITO) towards analyte ions; Zn(II), Cu(II), and Fe(II) ions were investigated by differential pulse voltammetry (DPV) under optimized conditions. It was found that the response of modified electrode towards the analytes was improved significantly as compared to the ITO electrode and resulted in limit of detections (LOD) of 9.88 pg/L, 8.33 μg/L and 1.15 μg/L, respectively. In addition, the detection limit of simultaneous detection quantification of Cu2 +, Zn2 + and Fe2 + ions could be achieved with the concentration 6.19 ng/L, 3.02 mg/L and 2.79 mg/L, respectively. It is worth to show that dicarboethoxy-calix [4]arene modified electrode is a promising candidate as electrochemical sensors for simultaneous and ultrasensitive heavy metal ions determination.

A quick detection for volatile organic compounds (VOCs), especially in the indoor environment is a must as the build-up level of VOCs is multiple times greater than outdoor environment. By using a surface potential probe, we have analyzed the interaction between copolysiloxane Langmuir-Blodgett (LB) thin films with several commercially used VOCs solvent, specifically chloroform (CHCl3), isopropyl alcohol (IPA) and dichloromethane (DCM). These copolysiloxane LB thin films, namely P50:50 and P25:75 had been deposited onto aluminium-coated substrates. Subsequently, the surface potential (ΔV) of copolysiloxane LB thin films were monitored during exposure to each solvent. Interaction of these thin films with each solvent produced non-identical changes in ΔV values. In addition, ∆Vmax value and halftime response for half ∆Vmax value (t50) were determined. Later, a figure of merit, ƒ was calculated to determine the optimum sensing material per solvent. The most promising candidates particularly as IPA solvent vapour sensors is P50:50 copolysiloxanes LB thin film that presented ΔVmax (106 mV), smallest halftime response for half ∆Vmax value achieved, t50 (65 s), and considerable ƒ (1.631 mV/s), as compared to others.

Two novel Schiff Base ligands are used in this work. These amphiphilic ligands were being chosen because of the suitability in forming Langmuir film by using Langmuir technique. Characterizations of these ligands were carried out through LB t the surface pressure-mean molecular area (П (ΔV-A) isotherms. The analysis made from extrapolating the П the estimated area and the radius of the ligand molecules The UV-Visible spectrometer was used to study the optical properties of the ligands. This study was made in order to recognize the fundamental properties of these ligands for future works on detecting ions applications. Two novel Schiff Base ligands are used in this work. These amphiphilic ligands were being chosen because of the suitability in forming Langmuir film by using Langmuir-Blodgett (LB)technique. Characterizations of these ligands were carried out through LB technique to obtain mean molecular area (П-A) and surface potential-mean molecular area . The analysis made from extrapolating the П-A graphs led to the result of the estimated area and the radius of the ligand molecules oriented on the air-water subphase.Visible spectrometer was used to study the optical properties of the ligands. This study was made in order to recognize the fundamental properties of these ligands for future works on detecting ions applications.Schiff Base Ligand; Langmuir-Blodgett technique; UV-Vis spectroscopy