Supramolecular Interaction of Atenolol and Propranolol with ß-Cyclodextrin Spectroscopic Characterization and Analytical Application.

Atenolol (ATE) and propranolol (PRO) inclusion complexes with ß-cyclodextrin have been investigated in aqueous solution. The aqueous solution was examined and characterized using UV-vis, fluorescence spectroscopy, and 1H NMR. The physical mixture was characterized using FTIR. The existence of inclusion complexes is confirmed by observing changes in spectroscopic properties. The ATE complex with ß-CD exhibited an interaction as host and (ß-CD) as a guest in a 1:1 ratio, with an inclusion constant K of 2.09 × 10-3 µM-1, as determined by the typical double-reciprocal graphs. Similarly, the PRO complex with ß-CD exhibited an interaction as host and (ß-CD) guest in 1:1 and 1:2 stoichiometry at the same time; the inclusion constants were K1 = 5.80 × 10-5 µM-1 and K2 = 4.67 × 10-8 µM-1, as determined by typical double-reciprocal graphs. The variables influencing the formation of the inclusion complexes were investigated and optimized. Based on the enhancement in fluorescence intensity due to the formation of inclusion complexes, spectrofluorometric methods were developed and validated for determination of each drug's pharmaceutical formulation. The quantification of the fluorescence intensity for ATE and PRO was conducted at λex/λem 226/302 nm and λex/λem 231/338 nm, respectively. Under the optimal reaction circumstances, linear relationships with good correlation coefficients of 0.9918 and 0.99 were found in the concentration ranges of 0.3-1.7 µM, and 0.1-1.1 µM for ATE and PRO, respectively. The limits of detection (LODs) were found to be 0.13 and 0.01 µM for ATE and PRO, respectively. The suggested approach was effectively applied to the analysis of both drugs' pharmaceutical formulations.

Development of Capillary Zone Electrophoresis Method for the Simultaneous Separation and Quantification of Metformin and Pioglitazone in Dosage Forms; and Comparison with HPLC Method.

A capillary zone electrophoretic (CZE) method was developed, validated, and applied for the assay of metformin (MET) and pioglitazone (PIO) in pharmaceutical formulations. The optimum running buffer composition was found to be 75 mmol/L phosphate buffer containing 30% acetonitrile (ACN) at pH 4.0. The optimum instrumental conditions were found to be injection time, 10 s; applied voltage, 25 kV; hydrodynamic injection pressure, 0.5 psi for 10 s, capillary temperature, 25 °C; and the detection wavelength, 210 nm. The quantifications were calculated based on the ratio of the peak areas of analytes to atenolol as an internal standard. The CZE method was validated in terms of accuracy (98.21-104.81%), intra- and inter-day precision of migration time and peak area (relative standard deviation ≤ 5%), linearity (correlation coefficients ≥ 0.9985), limit of detection (≤0.277 µg/mL), and limit of quantitation (≤0.315 µg/mL). The proposed method was applied for the analysis of PIO and MET both individually and in a combined dosage tablet formulation. All electrophoretic parameters were calculated and evaluated. A previously reported high-performance liquid chromatographic (HPLC) method was also applied to the same samples. A comprehensive comparison was then carried out for the analytical features of both methods CZE and HPLC. Comparable results were obtained with the advantage of reagent consumption and separation efficiency of CZE over HPLC and shorter analysis time by HPLC compared with CZE.

Radiolytic degradation of carbaryl in aqueous solution by gamma-irradiation/H2O2 process.

In this study the synergetic effect of gamma-ray and hydrogen peroxide on the degradation of carbaryl in aqueous solution were investigated. Aqueous solution of carbaryl was exposed to five different irradiation doses in the presence and absence of hydrogen peroxide. The intermediate species and aliphatic acids formed during irradiation were determined by Gas chromatography-Mass spectrometer and Ion Chromatography, respectively. It was found that the gamma-irradiation accelerate the degradation process of carbaryl with and without hydrogen peroxide. The inconstancy in pH, dissolved oxygen and total acidity was evaluated before and after treatment by gamma. It was found that the pH was decline from 6.71 to 5, dissolved oxygen from 2.64 to 0.9 mgL-1 and the total acidity was raised from 0.44 to 0.61 mgL-1. The entirely degradation of Carbaryl takes place at 3.0 kGy and 9.6 mM hydrogen peroxide, H2O2. As a consequence, the possible degradation pathway was suggested.

Application of Capillary Electrophoresis with Capacitively Coupled Contactless Conductivity Detection (CE-C4D): 2017-2020.

Capacitively coupled contactless conductivity detection (C4D) has emerged as influential to detect analytes that do not have chromogenic or fluorogenic functional group. Since our last review several new capillary electrophoresis (CE) methods coupled with (CE-C4D) have been communicated. The aim of this review is to give an update of the almost all the new applications of CE-C4D in the field of pharmaceutical, food and biomedical analysis covering the period from 2017 to April 2020. The utilization of CE with C4D in the areas of pharmaceutical, food and biomedical analysis is presented. Finally, concluding remarks and outlooks are discussed.

Multidimensional Gas Chromatography for Chiral Analysis.

Multidimensional gas chromatography (MDGC) is well-established GC method used for a diverse range of applications. Enantioselective MDGC (enantio-MDGC) has been suggested as the method of preference for the separation of extremely overlapping enantiomers. An extensive number of literatures describe enantio-MDGC of polychlorinated biphenyls, essential oils and flavor and fragrance and amino acids were reported. In this review, the applications of MDGC approaches both, heart cutting GC-GC and comprehensive GC × GC in chiral analysis is presented. Since the application of these techniques in this filed is very broad so it will be divided into sections according to the type of the compounds.

Application of gas and liquid chromatography coupled to time-of-flight mass spectrometry in pesticides: Multiresidue analysis.

Analysis of pesticide residues in water and food matrices is an active research area closely related to food safety and environmental issues. In this aspect mass spectrometry (MS) coupled to gas chromatography (GC) and liquid chromatography (LC) has been increasingly used in the analysis of pesticide residues in water and food. The increasing interest in application of high-resolution mass spectrometry with time-of-flight (TOF) and hybrid triple quadrupole TOF in pesticide analysis is due to its capability of performing both targeted and nontargeted analysis. This article discusses an overview of the application of GC-TOF-MS and LC-TOF-MS in water and food matrices.

Capillary electrophoresis method with UV-detection for analysis of free amino acids concentrations in food.

Simple and inexpensive capillary electrophoresis with UV-detection method (CE-UV) was optimized and validated for determination of six amino acids namely (alanine, asparagine, glutamine, proline, serine and valine) for Sudanese food. Amino acids in the samples were derivatized with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) prior to CE-UV analysis. Labeling reaction conditions (100mM borate buffer at pH 8.5, labeling reaction time 60min, temperature 70°C and NBD-Cl concentration 40mM) were systematically investigated. The optimal conditions for the separation were 100mM borate buffer at pH 9.7 and detected at 475nm. The method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision (repeatability) (RSD%) and accuracy (recovery). Good linearity was achieved for all amino acids (r(2)>0.9981) in the concentration range of 2.5-40mg/L. The LODs in the range of 0.32-0.56mg/L were obtained. Recoveries of amino acids ranging from 85% to 108%, (n=3) were obtained. The validated method was successfully applied for the determination of amino acids for Sudanese food samples.

Determination of acrylamide in Sudanese food by high performance liquid chromatography coupled with LTQ Orbitrap mass spectrometry.

A sample preparation method based on modified Quick, Easy, Cheap Effective, Rugged and Safe (QuEChERS) with aluminum oxide (Al2O3) as dispersive solid phase extraction (dSPE) material and high performance liquid chromatography-linear trap quadruple-Orbitrap-mass spectrometry (HPLC LTQ-Orbitrap MS) was established. The performance of two analytical columns namely Kinetex C18 and Rezex ROA-organic acid was compared for acrylamide separation. The method was validated in term of matrix effect, linear range (standard addition method), limit of detection (LOD), limit of quantification (LOQ), precision (RSD%) and recovery. Good linearity (r(2)>0.9979) was achieved using standard addition method in the concentration range 0-200µgkg(-1). The LOD is in the range from 2.91 to 4.04µgkg(-1) and 1.50 to 3.94µgkg(-1) for C18 and ROA columns, respectively. The precision of the method was ⩽7.3% and 5.6% for C18 and ROA columns, respectively. Recoveries of acrylamide ranging from 90% to 97%, (n=3) were obtained. The proposed Al2O3 dSPE method was successfully applied to the analysis of acrylamide in real food samples.

Sol-gel hybrid methyltrimethoxysilane-tetraethoxysilane as a new dispersive solid-phase extraction material for acrylamide determination in food with direct gas chromatography-mass spectrometry analysis.

A sol-gel hybrid sorbent, methyltrimethoxysilane-tetraethoxysilane (MTMOS-TEOS) was successfully used as new dispersive solid phase extraction (dSPE) sorbent material in the determination of acrylamide in several Sudanese foods and analysis using GC-MS. Several important dSPE parameters were optimised. Under the optimised conditions, excellent linearity (r(2)>0.9998) was achieved using matrix matched standard calibration in the concentration range 50-1000 µg kg(-1). The limits of detection (LOD) and limit of quantification ranged from 9.1 to 12.8 µg/kg and 27.8-38.9 µg/kg, respectively. The precision (RSD%) of the method was ⩽6.6% and recoveries of acrylamide obtained were in the range of 88-103%, (n=3). The LOD obtained is comparable with the LODs of primary secondary amine dSPE. The proposed MTMOS-TEOS dSPE method is direct and safe for acrylamide analysis, showed reliable method validation performances and good cleanup effects. It was successfully applied to the analysis of acrylamide in real food samples.