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

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

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 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

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

Synthesis and Application of Cobalt Oxide (Co3O4)-Impregnated Olive Stones Biochar for the Removal of Rifampicin and Tigecycline: Multivariate Controlled Performance

Cobalt oxide (Co3O4) nanoparticles supported on olive stone biochar (OSBC) was used as an efficient sorbent for rifampicin (RIFM) and tigecycline (TIGC) from wastewater. Thermal stabilities, morphologies, textures, and surface functionalities of two adsorbents; OSBC and Co-OSBC were compared. BET analysis indicated that Co-OSBC possesses a larger surface area (39.85 m2/g) and higher pore-volume compared to the pristine OSBC. FT-IR analysis showed the presence of critical functional groups on the surface of both adsorbents. SEM and EDX analyses showed the presence of both meso- and macropores and confirmed the presence of Co3O4 nanoparticles on the adsorbent surface. Batch adsorption studies were controlled using a two-level full-factorial design (2k-FFD). Adsorption efficiency of Co-OSBC was evaluated in terms of the % removal (%R) and the sorption capacity (qe, mg/g) as a function of four variables: pH, adsorbent dose (AD), drug concentration, and contact time (CT). A %R of 95.18% and 75.48% could be achieved for RIFM and TIGC, respectively. Equilibrium studies revealed that Langmuir model perfectly fit the adsorption of RIFM compared to Freundlich model for TIGC. Maximum adsorption capacity (qmax) for RIFM and TIGC was 61.10 and 25.94 mg/g, respectively. Adsorption kinetics of both drugs could be best represented using the pseudo-second order (PSO) model.This research was funded by Qatar University under the National Science Promotion Program, QUNSPP-(CAS)-2021-(108). The NSPP is managed by Qatar University Young Scientists Center (QUYSC), Doha, Qatar. The findings achieved herein are solely the responsibility of the author

Carbon-Based Materials (CBMs) for Determination and Remediation of Antimicrobials in Different Substrates: Wastewater and Infant Foods as Examples

The widespread use of antimicrobials within either a therapeutic or a veterinary rehearsal has resulted in a crisis on the long run. New strains of antimicrobial-resistant microorganisms have appeared. Contamination of water with pharmaceutically active materials is becoming a fact! and efficacy of wastewater treatment plants is a question. Adsorption is a promising technique for wastewater treatment. Carbon-based materials are among the most commonly used adsorbents for remediation purposes. Food production and commercialization are posing rigorous regulations. In this concern, almost all authoritarian societies are setting up standards for the maximum residue levels permissible in raw and processed food. Among these products is infant foods. The current trend is to use carbon-based and recycled from agricultural wastes, which can selectively remove target antimicrobials. Nanoparticles are among the most commonly used materials. With the enormous amount of data generated from an analytical process, there is a need for a powerful data processing technique. Factorial designs play an important role in not only minimalizing the number of experimental runs, and hence saving chemicals, resources, and reducing waste but also, they serve to improve the sensitivity and selectivity, the most important analytical outcomes

Eco-Structured Adsorptive Removal of Tigecycline from Wastewater: Date Pits’ Biochar versus the Magnetic Biochar

Non-magnetic and magnetic low-cost biochar (BC) from date pits (DP) were applied to remove tigecycline (TIGC) from TIGC-artificially contaminated water samples. Pristine biochar from DP (BCDP) and magnetite-decorated biochar (MBC-DP) were therefore prepared. Morphologies and surface chemistries of BCDP and MBC-DP were explored using FT-IR, Raman, SEM, EDX, TEM, and BET analyses. The obtained IR and Raman spectra confirmed the presence of magnetite on the surface of the MBC-DP. SEM results showed mesoporous surface for both adsorbents. BET analysis indicated higher amount of mesopores in MBC-DP. Box–Behnken (BB) design was utilized to optimize the treatment variables (pH, dose of the adsorbent (AD), concentration of TIGC [TIGC], and the contact time (CT)) and maximize the adsorptive power of both adsorbents. Higher % removal (%R), hitting 99.91%, was observed using MBC-DP compared to BCDP (77.31%). Maximum removal of TIGC (99.91%) was obtained using 120 mg/15 mL of MBC-DP for 10 min at pH 10. Equilibrium studies showed that Langmuir and Freundlich isotherms could best describe the adsorption of TIGC onto BCDP and MBC-DP, respectively, with a maximum adsorption capacity (qmax) of 57.14 mg/g using MBC-DP. Kinetics investigation showed that adsorption of TIGC onto both adsorbents could be best-fitted to a pseudo-second-order (PSO) model