Focused Ion Beam Tomography

To study the fundamental effect of shape and morphology of any material on its properties, it is very essential to know and study its morphology. Focused ion beam (FIB) tomography is a 3D chemical and structural relationship studying technique. The instrumentation of FIB looks like that of the scanning electron microscopy (SEM), but there is a major difference in the beam used for scanning. For SEM, a beam of electrons is used with scanning medium whereas in FIB, a much focused beam of ions is used for scanning. FIB can be used for lithography and ablation purposes, but due to advancements and high-energy focused beam, it is nowadays being used as a tomographic technique. Tomography is defined as imaging by sectoring or cross-sectioning any desired area. The hyphenation of FIB with energy-dispersive spectrometry or secondary ion mass spectrometry can give us elemental analysis with very high-resolution 3D images for a sample. This technique contributes to acquaintance of qualitative and quantitative analyses, 3D volume creations, and image processing. In this chapter, we will discuss the advancements in FIB instrumentation and its use as 3D imaging tool for different samples ranging from nanometer (nm)-sized materials to micrometer (μm)-sized biological samples

Potential Risk Assessment of Selected Polycyclic Aromatic Hydrocarbons in Vegetables Grown in Polluted and Non-polluted Areas of Sindh, Pakistan

Polycyclic Aromatic Hydrocarbons (PAHs) were determined in vegetables grown in Sindh, Pakistan. The vegetables were collected from both local markets and industrial areas where vegetation was carried out. All three types of vegetables, root vegetables, leafy vegetables and fruit vegetables were selected for analysis. The PAHs were extracted by Soxhlet extraction method and analysed by gas chromatography. The results showed that average concentration of PAHs in vegetables was ranged from 1.62±0.01 µg/kg to 144.52±2.51 µg/kg. From seven PAHs analyzed, the fluorene was found to be present in almost all vegetable samples and was highest in bitter guard that is 144.52±2.51 µg/kg. Like fluorene, naphthalene and anthracene were also present in all the vegetables but their concentration was not very high (6.89±0.03 µg/kg for naphthalene and 2.18±0.01 for anthracene). Higher concentration of PAHs was observed in samples collected from industrial areas due to the fact that industrial smoke could easily be absorbed by the vegetables grown in those areas

Modified electrochemical sensor via supramolecular structural functionalized graphene oxide for ultra-sensitive detection of gallic acid

Gallic acid (GA) is a synthetic polyphenolic compound that has been increasing interest due to its diverse biological activities, including anti-inflammatory, antioxidant, anti-tumor, scavenging free radicals, protecting cardiovascular diseases, and hypertension-lowering properties. The precise and rapid determination of GA content holds significant importance for human health. In this study, we present a cost-effective and highly sensitive electrochemical sensor employing a nanocomposite material, diester calix[4]arene functionalized graphene oxide (DEC4/GO) for the ultrasensitive detection of GA. The characterization of the as-synthesized nanocomposite material was carried out using various techniques, such as Fourier-Transform infrared (FT-IR), Raman spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Tunneling Electron Microscopy (TEM), to ascertain its chemical composition, crystalline nature, phase purity, and structural morphology. The uniform deposition of DEC4/GO on the surface of a bare glass carbon electrode (GCE) was achieved via a drop casting method. In addition, the developed sensor DEC4/GO/GCE exhibits exceptional electrochemical response towards GA under optimized conditions, such as pH -7 phosphate-buffered saline (PBS) as a supporting electrolyte, a scan rate of 110 mV/s, and an applied potential window between −0.2 V and 0.8 V. The as-developed sensor demonstrated a wide linear dynamic range of 10–100 μM, resulting a brilliant linear calibration obtained for GA. Furthermore, the limit of detection (LOD) and quantification (LOQ) of the developed sensor were calculated as 0.01 and 0.03 μM respectively, lower than those reported for the other GA sensors. To validate the feasibility of our developed method, we analyzed the GA content in wine and green tea samples, achieving good recovery results. Overall, this study presents a promising electrochemical sensor platform for ultrasensitive detection of GA holding potential implications for various applications in health monitoring and food analysis

Synthesis of Sheet Like Morphology of NiO for Sensitive and Selective Determination of Urea

An efficient and simple method has been demonstrated for the synthesis of nickel oxide nanostructures using urea as a capping agent. The nanosheet-like morphology was confirmed by scanning electron microscopy, crystalline nature was studied by using the X-ray diffraction (XRD) and surface area of nanomaterial was investigated by automated sorption analyzer. Then synthesized NiO nanostructures were used to fabricate the surface of glassy carbon electrode (GCE). The electrocatalytic parameters of modified NiO/GCE electrode were investigated by using various techniques such as electrochemical impedance spectroscopy (EIS), square wave voltammetry (SWV), differential pulse voltammetry (DPV), normal pulse voltammetry (NPV) and cyclic voltammetry (CV) and chronoamperometry. Various working experimental conditions were optimized in order to attain the highest sensitivity for the determination of urea and the highest peak current 1032 μA of response were obtained at 100 μM concentration of urea. A linear calibration plot was obtained for peak current versus concentration of urea in the range of 10 μM urea to 80 μM urea with a good detection limit of 2 μM. The proposed working strategy was successfully employed for the estimation of urea in human urine samples and the obtained results are found satisfactory. The newly functional urea sensor can be exploited at large scale as an alternative analytical device beside to the other reported urea sensorsValiderad;2018;Nivå 1;2018-02-12 (andbra)</p

A NiO-nanostructure-based electrochemical sensor functionalized with supramolecular structures for the ultra-sensitive detection of the endocrine disruptor bisphenol S in an aquatic environment

Herein, NiO nanoparticles (NPs) functionalized with a para-hexanitrocalix[6]arene derivative (p-HNC6/NiO) were synthesized by using a facile method and applied as a selective electrochemical sensor for the determination of bisphenol S (BPS) in real samples. Moreover, the functional interactions, phase purities, surface morphologies and elemental compositions of the synthesized p-HNC6/NiO NPs were investigated via advanced analytical tools, such as Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). Additionally, the synthesized p-HNC6/NiO NPs were cast on the surface of a bare glassy carbon electrode (GCE) via a drop casting method, which resulted in uniform deposition of p-HNC6/NiO/GCE over the surface of the GCE. Additionally, the developed p-HNC6/NiO/GCE sensor demonstrated an outstanding electrochemical response to BPS under optimized conditions, including a supporting electrolyte, a Briton-Robinson buffer electrolyte at pH 4, a scan rate of 110 mV s−1 and a potential window of between −0.2 and 1.0 V. The wide linear dynamic range was optimized to 0.8-70 μM to obtain a brilliant linear calibration curve for BPS. The limit of detection (LOD) and limit of quantification (LOQ) of the developed sensor were estimated to be 0.0059 and 0.019 μM, respectively, which are lower than those of reported sensors for BPS. The feasibility of the developed method was successfully assessed by analyzing the content of BPS in waste water samples, and good recoveries were achieved