Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015
The solid inclusion complex of gemifloxacin (GFX) and hydroxyl propyl β-cyclodextrin (HPβ-CD) was... more The solid inclusion complex of gemifloxacin (GFX) and hydroxyl propyl β-cyclodextrin (HPβ-CD) was prepared and examined by UV-visible, FTIR, NMR, electrospray ionization mass spectrometry (ESI-MS) and fluorescence spectroscopy. The formation of inclusion complex has been confirmed on the basis of changes of spectroscopic properties. Further the interaction between GFX and HPβ-CD was studied using molecular modeling approaches. The results showed that HPβCD reacted with GFX to form a 1:1 host-guest inclusion complex. Based on the enhancement of the fluorescence intensity of GFX produced through complex formation, a simple, accurate, rapid and highly sensitive spectrofluorometric method for the determination of GFX in pharmaceutical formulation was developed. The linear relationships between the intensity and GFX concentration was obtained in the concentration range of 20-140 ng/mL with good correlation coefficients (0.9997). The limit of detection (LOD) was found to be 4 ng/mL. The proposed method was successfully applied to the analysis of GFX in pharmaceutical preparation.
American academic & scholarly research journal, 2012
Spectrophotometric study was carried out, for the first time, to investigate the reaction between... more Spectrophotometric study was carried out, for the first time, to investigate the reaction between the antipsychotic Olanzapine (OLP) and 1,2-naphthoquinone -4-sulphonate (NQS) reagent. In alkaline medium (pH 13), an orange-colored product exhibiting maximum absorption peak (λmax) at 454nm was produced. The stoichiometry of the reaction was determined and the reaction mechanism was postulated. This colordeveloping reaction was successfully employed in the development of simple and rapid spectrophotometric method for determination of OLP in its pharmaceutical dosage forms. Under the optimized reaction conditions, Beer’s law correlating the absorbance (A) with OLP concentration (C) was obeyed in the range of 0.4–4 µgml −1 . The regression equation for the calibration data was A = 0.0372 + 0.1637C, with good correlation coefficient (0.9997). The molar absorptivity (e) was 5.6×10 4 l mol −1 cm −1 . The limits of detection, quantification and Sandell sensitivity were 0.09, 0.29 µgml −1 an...
Abstract The inclusion complexes of imazapyr (IMA) with 2-hydroxypropyl(β/γ) cyclodextrins (HP β/... more Abstract The inclusion complexes of imazapyr (IMA) with 2-hydroxypropyl(β/γ) cyclodextrins (HP β/γ-CD), have been studied in aqueous media and in the solid state. In this work, fluorescence spectroscopy, electrospray-ionization mass spectrometry (ESI-MS), and 1HNMR were used to investigate and characterize the inclusion complexes of IMA with the cyclodextrins in solutions. The solid state complexes were obtained by freeze drying and were characterized by Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffraction (PXRD). The most predominant complexes of IMA with both hosts are the 1:1 guest: host complexes. The association constants of IMA-HP β-CD and IMA-HP γ-CD were 115 ± 23 and 215 ± 80 L mol−1, respectively. Molecular dynamic (MD) simulations were used to monitor the mode of inclusion and also to investigate the stability of these complexes in aqueous media at atomistic levels. The results obtained have indicated that these inclusion complexes are highly stable in aqueous media, thereby corroborating the experimental results. Additionally, it has been demonstrated that in addition to hydrophobic effects and van der Waals interactions the presence of hydrogen bonding interactions of the type H O and CH O between the guest and the host have enhanced the stability of these complexes remarkably.
Critical reviews in analytical chemistry, Jan 3, 2018
Multidimensional gas chromatography (MDGC) is well-established GC method used for a diverse range... more 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.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, Jan 5, 2018
The inclusion complexes of imazapyr (IMA) with cucurbit[n]uril, CB[n] (n=6-8), have been investig... more The inclusion complexes of imazapyr (IMA) with cucurbit[n]uril, CB[n] (n=6-8), have been investigated. Fluorescence spectroscopy, MALDI-TOF, and 1HNMR were used to investigate and characterize the inclusion complexation of IMA and CB[n] in solutions. Whereas the solid state complexes have been characterized by Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffraction (PXRD). IMA was found to form 1:1 complexes with CB[n] with association constants ranging from 5.80×102-2.65×103. The guest molecule IMA was found to encapsulate into the larger cavities of CB[7] and CB[8], whereas with CB[6] the molecule remains outside the cavity. Molecular dynamic (MD) simulations were used to follow the inclusion process at an atomistic level to study the mechanism and stability of inclusion. The results obtained showed that inclusion complexes of IMA with both CB[7] and CB[8] are highly stable in aqueous media, but the CB[6] smaller cavity size prohibited the formation of an incl...
Analysis of pesticide residues in water and food matrices is an active research area closely rela... more 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.
Capacitively coupled contactless conductivity detection (C(4) D) has appeared as a powerful techn... more Capacitively coupled contactless conductivity detection (C(4) D) has appeared as a powerful technique for the detection of compounds lacking chromogenic or fluorogenic group. Since our last review (Biomedical Chromatography 2014; 28: 1502-1506) several new capillary electrophoresis (CE)-C(4) D methods have been reported. This review provides an update of the most recent utilization of CE-C(4) D in the field of pharmaceutical, biomedical and food analysis covering the period from February 2014 to October 2016. The use of CE with C(4) D in the pharmaceutical field has been shown in many papers. Examples illustrate the applicability of CE-C(4) D in the fields of pharmaceutical, biomedical and food analysis. Finally, general conclusions and perspectives are provided.
In this a study tomato sampleswere collected from Khartoum, extracted with acetone, dichlorometha... more In this a study tomato sampleswere collected from Khartoum, extracted with acetone, dichloromethane and petroleum ether (1:1:1) and cleaned up by florisil column. Malathion quantitative determination is carried out by gas chromatograph-mass spectrometerusing the optimum ionization mode electron ionization (EI). The detection ofmalathionis confirmed by retention time and comparison of primary and secondary ions.Recovery studies were performed at two spikes (0.5,0.25mg kg -1 ) fortification levels of malathion and the recovery obtained ranged from 81% to 97%. The method showed good linearity(R²> 0.995) over the range assayed (from 0.05 to 7.0mg L -1 ) and the calculated limits of detection (LOD) and quantification(LOQ) were0.03 mg kg -1 and 0.11 mg kg -1 , respectively. These limits werelower than the maximum residue levels(MRL) established by European legislations (0.5mg kg -1 ).
The supramolecular interaction of nizatidine (NIZ) and β-cyclodextrin (β-CD) has been studied by ... more The supramolecular interaction of nizatidine (NIZ) and β-cyclodextrin (β-CD) has been studied by spectrofluorimetry. The results showed that β-CD reacted with NIZ to form an inclusion complex.The NIZ-β-CDcomplex formed a host-guest complex in 1:1 stoichiometryand inclusion constant (K = 3.15×102 L mol-1) and wasascertained by the typical double reciprocal plots. Furthermore, the thermodynamic parameters (ΔH°, ΔS° and ΔG°)associated with the inclusion process were also determined. Based on the significant enhancement of thefluorescence intensity of NIZ produced through complex formation, a simple, accurate, rapid and highly sensitivespectrofluorometric method for the determination of NIZ in aqueous solution in the presence of β-CD wasdeveloped. The measurement of relative fluorescence intensity was carried with excitation at 314 nm.The factors affecting the inclusion complex formation were studied and optimized. Under the optimum reactionconditions, linear relationships with good cor...
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015
The solid inclusion complex of gemifloxacin (GFX) and hydroxyl propyl β-cyclodextrin (HPβ-CD) was... more The solid inclusion complex of gemifloxacin (GFX) and hydroxyl propyl β-cyclodextrin (HPβ-CD) was prepared and examined by UV-visible, FTIR, NMR, electrospray ionization mass spectrometry (ESI-MS) and fluorescence spectroscopy. The formation of inclusion complex has been confirmed on the basis of changes of spectroscopic properties. Further the interaction between GFX and HPβ-CD was studied using molecular modeling approaches. The results showed that HPβCD reacted with GFX to form a 1:1 host-guest inclusion complex. Based on the enhancement of the fluorescence intensity of GFX produced through complex formation, a simple, accurate, rapid and highly sensitive spectrofluorometric method for the determination of GFX in pharmaceutical formulation was developed. The linear relationships between the intensity and GFX concentration was obtained in the concentration range of 20-140 ng/mL with good correlation coefficients (0.9997). The limit of detection (LOD) was found to be 4 ng/mL. The proposed method was successfully applied to the analysis of GFX in pharmaceutical preparation.
American academic & scholarly research journal, 2012
Spectrophotometric study was carried out, for the first time, to investigate the reaction between... more Spectrophotometric study was carried out, for the first time, to investigate the reaction between the antipsychotic Olanzapine (OLP) and 1,2-naphthoquinone -4-sulphonate (NQS) reagent. In alkaline medium (pH 13), an orange-colored product exhibiting maximum absorption peak (λmax) at 454nm was produced. The stoichiometry of the reaction was determined and the reaction mechanism was postulated. This colordeveloping reaction was successfully employed in the development of simple and rapid spectrophotometric method for determination of OLP in its pharmaceutical dosage forms. Under the optimized reaction conditions, Beer’s law correlating the absorbance (A) with OLP concentration (C) was obeyed in the range of 0.4–4 µgml −1 . The regression equation for the calibration data was A = 0.0372 + 0.1637C, with good correlation coefficient (0.9997). The molar absorptivity (e) was 5.6×10 4 l mol −1 cm −1 . The limits of detection, quantification and Sandell sensitivity were 0.09, 0.29 µgml −1 an...
Abstract The inclusion complexes of imazapyr (IMA) with 2-hydroxypropyl(β/γ) cyclodextrins (HP β/... more Abstract The inclusion complexes of imazapyr (IMA) with 2-hydroxypropyl(β/γ) cyclodextrins (HP β/γ-CD), have been studied in aqueous media and in the solid state. In this work, fluorescence spectroscopy, electrospray-ionization mass spectrometry (ESI-MS), and 1HNMR were used to investigate and characterize the inclusion complexes of IMA with the cyclodextrins in solutions. The solid state complexes were obtained by freeze drying and were characterized by Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffraction (PXRD). The most predominant complexes of IMA with both hosts are the 1:1 guest: host complexes. The association constants of IMA-HP β-CD and IMA-HP γ-CD were 115 ± 23 and 215 ± 80 L mol−1, respectively. Molecular dynamic (MD) simulations were used to monitor the mode of inclusion and also to investigate the stability of these complexes in aqueous media at atomistic levels. The results obtained have indicated that these inclusion complexes are highly stable in aqueous media, thereby corroborating the experimental results. Additionally, it has been demonstrated that in addition to hydrophobic effects and van der Waals interactions the presence of hydrogen bonding interactions of the type H O and CH O between the guest and the host have enhanced the stability of these complexes remarkably.
Critical reviews in analytical chemistry, Jan 3, 2018
Multidimensional gas chromatography (MDGC) is well-established GC method used for a diverse range... more 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.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, Jan 5, 2018
The inclusion complexes of imazapyr (IMA) with cucurbit[n]uril, CB[n] (n=6-8), have been investig... more The inclusion complexes of imazapyr (IMA) with cucurbit[n]uril, CB[n] (n=6-8), have been investigated. Fluorescence spectroscopy, MALDI-TOF, and 1HNMR were used to investigate and characterize the inclusion complexation of IMA and CB[n] in solutions. Whereas the solid state complexes have been characterized by Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffraction (PXRD). IMA was found to form 1:1 complexes with CB[n] with association constants ranging from 5.80×102-2.65×103. The guest molecule IMA was found to encapsulate into the larger cavities of CB[7] and CB[8], whereas with CB[6] the molecule remains outside the cavity. Molecular dynamic (MD) simulations were used to follow the inclusion process at an atomistic level to study the mechanism and stability of inclusion. The results obtained showed that inclusion complexes of IMA with both CB[7] and CB[8] are highly stable in aqueous media, but the CB[6] smaller cavity size prohibited the formation of an incl...
Analysis of pesticide residues in water and food matrices is an active research area closely rela... more 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.
Capacitively coupled contactless conductivity detection (C(4) D) has appeared as a powerful techn... more Capacitively coupled contactless conductivity detection (C(4) D) has appeared as a powerful technique for the detection of compounds lacking chromogenic or fluorogenic group. Since our last review (Biomedical Chromatography 2014; 28: 1502-1506) several new capillary electrophoresis (CE)-C(4) D methods have been reported. This review provides an update of the most recent utilization of CE-C(4) D in the field of pharmaceutical, biomedical and food analysis covering the period from February 2014 to October 2016. The use of CE with C(4) D in the pharmaceutical field has been shown in many papers. Examples illustrate the applicability of CE-C(4) D in the fields of pharmaceutical, biomedical and food analysis. Finally, general conclusions and perspectives are provided.
In this a study tomato sampleswere collected from Khartoum, extracted with acetone, dichlorometha... more In this a study tomato sampleswere collected from Khartoum, extracted with acetone, dichloromethane and petroleum ether (1:1:1) and cleaned up by florisil column. Malathion quantitative determination is carried out by gas chromatograph-mass spectrometerusing the optimum ionization mode electron ionization (EI). The detection ofmalathionis confirmed by retention time and comparison of primary and secondary ions.Recovery studies were performed at two spikes (0.5,0.25mg kg -1 ) fortification levels of malathion and the recovery obtained ranged from 81% to 97%. The method showed good linearity(R²> 0.995) over the range assayed (from 0.05 to 7.0mg L -1 ) and the calculated limits of detection (LOD) and quantification(LOQ) were0.03 mg kg -1 and 0.11 mg kg -1 , respectively. These limits werelower than the maximum residue levels(MRL) established by European legislations (0.5mg kg -1 ).
The supramolecular interaction of nizatidine (NIZ) and β-cyclodextrin (β-CD) has been studied by ... more The supramolecular interaction of nizatidine (NIZ) and β-cyclodextrin (β-CD) has been studied by spectrofluorimetry. The results showed that β-CD reacted with NIZ to form an inclusion complex.The NIZ-β-CDcomplex formed a host-guest complex in 1:1 stoichiometryand inclusion constant (K = 3.15×102 L mol-1) and wasascertained by the typical double reciprocal plots. Furthermore, the thermodynamic parameters (ΔH°, ΔS° and ΔG°)associated with the inclusion process were also determined. Based on the significant enhancement of thefluorescence intensity of NIZ produced through complex formation, a simple, accurate, rapid and highly sensitivespectrofluorometric method for the determination of NIZ in aqueous solution in the presence of β-CD wasdeveloped. The measurement of relative fluorescence intensity was carried with excitation at 314 nm.The factors affecting the inclusion complex formation were studied and optimized. Under the optimum reactionconditions, linear relationships with good cor...
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