Electrochemical Impedance Spectroscopy (EIS) in Food, Water, and Drug Analyses: Recent Advances and Applications

Electrochemical impedance spectroscopy (EIS) is a potent electrochemical technique with a variety of applications. EIS measurements involve the application of an alternating current (AC) voltage (or current) to the system under investigation, followed by measurement of the response in the form of AC current (or voltage) as a function of frequency. By and large, EIS is an exceptionally attractive in terms of applications. Being nondestructive with a feasibility of implementation to the system to be measured and the usefulness of data obtained in characterizing the studied systems, electrochemical impedance spectroscopy has realms of applications. As food and water safety and security is becoming a universal concern, the need for a technique that can detect water and food contaminants with relatively high sensitivity and selectivity is evolving. EIS has started to realize its potential with a wide-term use in water and food analyses

Tourism Development of the Cultural Heritage and Archaeological Sites within the National Project for Urban Sustainable Development in Egypt

Egypt is located on the north-eastern side of Africa. Egypt has many archaeological sites classified in the World Heritage List. Tourism development of the Cultural Heritage, historical locations and archeological sites supporting the National Economy and Local Society. Egypt also has a massive number of cultural-historical landmarks and unique architectural constructions such as the great pyramids of Giza, Saqqara, Dahshur and Abusir; the temples of Luxor, Aswan, and Abu Simbel; the valley of the kings, and other extraordinary monumental attractions that worth studying. The study throws light on the tourism development of the Cultural Heritage, historical landmarks, and archeological sites that consider one of the essential resources supporting the National Economy and Local Society. Egypt has always relied on tourism and its historical sights to raise its Economy by developing archaeological sites and historical locations

Analytical Calibrations: Schemes, Manuals, and Metrological Deliberations

Chemical measurement processes (CMPs) must be performed in a setup of controlled statistical conditions. Thus, validation of such a measurement process and assessment of its ability to accurately measure the analyte is important. Analytical calibration is the most crucial step in any analytical procedure targeting the estimation of analyte concentration. As a key component of any validation procedure, calibration must be properly conducted. To achieve that, firm knowledge with the realms of the calibration process must exist. Several jurisdictions help to build up this acquaintance, including the terminology and definitions, the international guidelines and how they differ, schemes and manuals to be used to build a calibration model, metrological considerations, and assessment procedures. Careful thinking prior to any of the previous calibration aspects is necessary and helps to improve the product of the calibration process. Throughout this chapter, aspects of the calibration assembly will be thoroughly discussed. Different types of calibration will be revealed with a focus on analytical calibration for a CMP. Steps for a successful calibration will be described. The reader will be able to use information given throughout this chapter as a guide for an effective calibration process

Eco-structured biosorptive removal of basic fuchsin using pistachio nutshells: A definitive screening design-based approach

Biosorptive removal of basic fuchsin (BF) from wastewater samples was achieved using the recycled agro-wastes of pistachio nut shells (PNS). Seven adsorbents were developed; raw shells (RPNS) and the thermally activated biomasses at six different temperatures (250–500 °C). Two measures were implemented to assess the performance of utilized adsorbents; %removal (%R) and adsorption capacity (qe). RPNS proved to be the best among the tested adsorbents. A smart approach, definitive-screening design (DSD) was operated to test the impact of independent variables on the adsorption capacity of RPNS. pH, adsorbent dose (AD), dye concentration (DC), and stirring time (ST), were the tested variables. Analysis of variance (ANOVA), control, and quality charts helped establishing regression model. Characterization was performed using Fourier- transform infrared (FT-IR)/Raman spectroscopies together with thermogravimetric analysis (TGA) and scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX) analyses. The surface area and other textural properties were determined using the Brunauer Emmett-Teller (BET) analysis. Removal of 99.71% of BF with an adsorption capacity of 118.2 mg/g could be achieved using a factorial blend of pH 12, 100 mg/50 mL of RPNS, and 250 ppm BF for 20 min. Equilibrium studies reveal that the adsorption is physisorption with adsorption energy of 7.45 kJ/mol as indicated by Dubinin-Radushkevich (DR) and Langmuir isotherms. Moreover, adsorption follows pseudo-second-order kinetics with respect to BF and is controlled by the adsorption rate.This work was made possible by Qatar University Internal Student Grant [QUST-2-CAS-2019-18] from Qatar University. The statements made herein are solely the responsibility of the authors. The publication of this article was funded by the Qatar National Library.Scopu

Bio-Waste Aloe vera Leaves as an efficient adsorbent for Titan Yellow from Wastewater: Structuring of a novel adsorbent using Plackett-Burman factorial design

Titan yellow (TY), a triazene azo dye, was removed from contaminated wastewater samples using a green adsorbent recycled from Aloe vera leaves (AV) waste. Two adsorbents were developed-air-dried Aloe vera (ADAV) and thermally treated Aloe vera (TTAV). Adsorption efficacy of both adsorbents was assessed in terms of percent removal (%R) of TY and adsorption capacity (qe). ADAV had a better performance compared to TTAV. Plackett-Burman design (PBD) was exploited to establish the experimental pattern of the study. Four variables were studied: pH, adsorbent dose (AD), dye concentration (DC), and stirring time (ST). Analysis of variance (ANOVA) at 95.0 confidence interval (CI), control, and quality charts helped establish regression model(s). Characterization of both adsorbents was performed using FT-IR/Raman spectroscopy together with TGA/dTGA and SEM/energy dispersive X-ray spectroscopy (EDX) analyses. Textural properties were determined using nitrogen adsorption isotherms at 77 K. Results showed that the surface areas of ADAV and TTAV300 were 3.940 and 7.076 m2/g, respectively. Raman analysis showed that the TTAV had clear Dand G-bands. Equilibrium studies revealed that data were well fitted to Freundlich isotherm with a maximum adsorption capacity of 55.25 mg/g using Langmuir equation, and the adsorption was physisorption. Adsorption followed a pseudo-second order that occurred in two steps-diffusion and then adsorption. - 2019 by the authors.The project members would like to extend their special thanks to the Central Lab Unit (CLU) at the Qatar University. This work was made possible by Qatar University Internal Student Grant [QUST-2-CAS-2019-18] from Qatar University. The statements made herein are solely the responsibility of the authors. The publication of this article was funded by the Qatar National LibraryScopu

Kinetics of alkoxysilanes hydrolysis: An empirical approach

Alkoxysilanes and organoalkoxysilanes are primary materials in several industries, e.g. coating, anti-corrosion treatment, fabrication of stationary phase for chromatography, and coupling agents. The hydrolytic polycondensation reactions and final product can be controlled by adjusting the hydrolysis reaction, which was investigated under a variety of conditions, such as different alkoxysilanes, solvents, and catalysts by using gas chromatography. The hydrolysis rate of alkoxysilanes shows a dependence on the alkoxysilane structure (especially the organic attachments), solvent properties, and the catalyst dissociation constant and solubility. Some of the alkoxysilanes exhibit intramolecular catalysis. Hydrogen bonding plays an important role in the enhancement of the hydrolysis reaction, as well as the dipole moment of the alkoxysilanes, especially in acetonitrile. There is a relationship between the experimentally calculated polarity by the Taft equation and the reactivity, but it shows different responses depending on the solvent. It was found that negative and positive charges are respectively accumulated in the transition state in alkaline and acidic media. The reaction mechanisms are somewhat different from those previously suggested. Finally, it was found that enthalpy–entropy compensation (EEC) effect and isokinetic relationships (IKR) are exhibited during the hydrolysis of CTES in different solvents and catalysts; therefore, the reaction has a linear free energy relationship (LFER).The publication of this article was funded by the Qatar National Library.Scopu

Application of Plackett-Burman Design for Spectrochemical Determination of the Last-Resort Antibiotic, Tigecycline, in Pure Form and in Pharmaceuticals: Investigation of Thermodynamics and Kinetics.

Tigecycline (TIGC) reacts with 7,7,8,8-tetracyanoquinodimethane (TCNQ) to form a bright green charge transfer complex (CTC). The spectrum of the CTC showed multiple charge transfer bands with a major peak at 843 nm. The Plackett-Burman design (PBD) was used to investigate the process variables with the objective being set to obtaining the maximum absorbance and thus sensitivity. Four variables, three of which were numerical (temperature-Temp; reagent volume-RV; reaction time-RT) and one non-numerical (diluting solvent-DS), were studied. The maximum absorbance was achieved using a factorial blend of Temp: 25 °C, RV: 0.50 mL, RT: 60 min, and acetonitrile (ACN) as a DS. The molecular composition that was investigated using Job's method showed a 1:1 CTC. The method's validation was performed following the International Conference of Harmonization (ICH) guidelines. The linearity was achieved over a range of 0.5-10 µg mL with the limits of detection (LOD) and quantification (LOQ) of 166 and 504 ng mL, respectively. The method was applicable to TIGC per se and in formulations without interferences from common additives. The application of the Benesi-Hildebrand equation revealed the formation of a stable complex with a standard Gibbs free energy change (∆) value of -26.42 to -27.95 kJ/mol. A study of the reaction kinetics revealed that the CTC formation could be best described using a pseudo-first-order reaction

Electrochemical Analysis of Sulfisoxazole Using Glassy Carbon Electrode (GCE) and MWCNTs/Rare Earth Oxide (CeO2 and Yb2O3) Modified-GCE Sensors

In this work, new electrochemical sensors based on the modification of glassy carbon electrode (GCE) with multiwalled carbon nanotubes (MWCNTs)—rare metal oxides (REMO) nanocomposites were fabricated by drop-to-drop method of MWCNTs-REMO dispersion in ethanol. REMO nanoparticles were synthesized by precipitation followed by hydrothermal treatment at 180◦C in absence and presence of Triton™ X-100 surfactant. Cyclic voltammetry (CV) analysis using MWCNTs-CeO2@GCE and MWCNTs-Yb2O3@GCE sensors were used for the analysis of sulfisoxazole (SFX) drug in water samples. The results of CV analysis showed that MWCNTs-REMO@GCE sensors have up to 40-fold higher sensitivity with CeO2 compared to the bare GCE sensor. The estimated values of the limit of detection (LoD) of this electrochemical sensing using MWCNTs-CeO2@GCE and MWCNTs-Yb2O3@GCE electrodes reached 0.4 and 0.7 µM SFX in phosphate buffer pH = 7, respectively. These findings indicate that MWCNTs-REMO@GCE electrodes are potential sensors for analysis of sulfonamide drugs in water and biological samples.Qatar University Internal Student Grant - No. QUST-1-CAS-2022-33

Application of Infrared Spectroscopy in the Characterization of Lignocellulosic Biomasses Utilized in Wastewater Treatment

Global economies are confronting major energy challenges. Mitigating the energy depletion crisis and finding alternative and unconventional energy sources have been subjects for many investigations. Plant-sourced biomasses have started to attract global attention as a renewable energy source. Maximizing the performance of the biomass feedstock in different applications requires the availability of reliable and cost-effective techniques for characterization of the biomass. Comprehending the structure of lignocellulosic biomass is a very important way to assess the feasibility of bond formation and functionalization, structural architecture, and hence sculpting of the corresponding structure−property liaison. Over the past decades, non-invasive techniques have brought many pros that make them a valuable tool in depicting the structure of lignocellulosic materials. The current chapter will be focused on the applications of Fourier transform infrared (FTIR) spectroscopy especially in the mid-infrared region in the compositional and structural analysis of lignocellulosic biomasses. The chapter will provide a display of examples from the literature for the application of FTIR spectroscopy in finding the composition of various biomasses obtained from different parts of plants and applied for wastewater treatment. A comparison between biomasses and physically/chemically treated products will be discussed