Determination of p-aminohippuric acid with β-cyclodextrin sensitized fluorescence spectrometry (original) (raw)
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Determination of p-aminohippuric acid with b- cyclodextrin sensitized fluorescence spectrometry
Sensitive spectrofluorometric and liquid chromatography with fluorescence detection methods have been developed for detection and determination of para-aminohippuric acid (PAH), one of the commonly used markers for estimating effective renal plasma flow, in the presence of b-cyclodextrin (b-CD). Fluorescence signals have been enhanced with the addition of b-CD to the drug aqueous solution. The 1 : 2 (host–guest) inclusion between PAH and cyclodextrin was evident by mass spectrometry and density functional theory (DFT) calculations supporting the formation of an excimer state at 355 nm. Factors that affect the PAH interaction with cyclodextrin have been investigated such as the size of the cyclodextrin cavity, the concentration of PAH, the concentration of cyclodextrin and pH effects. A calibration curve was established for the spectrofluorometric data of PAH with b-CD in the concentration range of 0.05–100 mM of PAH and the detection limit was 0.015 mM. HPLC with fluorescence detection was investigated in the presence of b-CD in the mobile phase. It was found that the calibration curve slope increased as the concentration of b-CD increased. Finally urine samples were spiked with 100 mM and 500 mM of PAH and showed recoveries in the range of 104–118% and 99.2–103%, respectively.
Probing inclusion complexes of cyclodextrins with amino acids by physicochemical approach
Carbohydrate Polymers, 2016
Surface tensions of the solutions were determined by platinum ring detachment technique using a Tensiometer (K9, KRŰSS; Germany) at 298.15 K. Accuracy of the study was ±0.1 mN m 1. Temperature of the system was maintained by circulating thermostated water through a double-wall glass vessel holding the solution. Conductivities of the solutions were studied by Mettler Toledo Seven Multi conductivity meter having uncertainty 1.0 µSm-1. The study was carried out in a thermostated water bath at 298.15K with uncertainty ±0.01K. HPLC grade water was used with specific conductance 6.0 µS m-1. The conductivity cell was calibrated using 0.01M aqueous KCl solution. The densities (ρ) of the solutions were studied by vibrating U-tube Anton Paar digital density meter (DMA 4500M) having precision ±0.00005 g cm-3 and uncertainty in temperature was ±0.01K. The density meter was calibrated by standard method [20]. Viscosities (η) were determined by Brookfield DV-III Ultra Programmable Rheometer with spindle size 42. The detail has already been depicted before [20]. Refractive indexes of the solutions were studied with a Digital Refractometer from Mettler Toledo having uncertainty ±0.0002 units. The detail has already been described before [20]. 1 H NMR spectra were recorded in D2O at 300 MHz using Bruker ADVANCE 300 MHz instrument at 298 K. Signals are quoted as δ values in ppm using residual protonated solvent signals as internal standard (D2O : δ 4.79 ppm). Data are reported as chemical shift. In each titration initially 0.5 mL 1.0 mM amino acid solution was taken and then 10 µL 10 mM CD solution was added into it at five several times.
Cyclodextrins (CDs) are a family of cyclic oligosaccharides composed of a-(1,4)-linked glucopyranose subunits. The most important feature of CDs is their ability to form inclusion complexes (host-guest complexes) with a very wide range of solid, liquid and gaseous compounds by a molecular complexation. During the last decade, a considerable number of research papers has been focused on the use of CDs to enhance fluorescence intensity of different analytes and to develop CD-induced spectrofluorimetric method. In this review, the various spectrofluorimetric methods based on host-inclusion complex are presented.
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 2000
In this work, the molecular conformation, vibrational and electronic analysis of para-aminohippuric acid (pAHA, C9H10N2O3) were presented for the ground state using experimental techniques (FT-IR, FT-Raman and UV) and density functional theory (DFT) employing B3LYP exchange correlation with the 6-311++G(d,p) basis set. FT-IR and FT-Raman spectra were recorded in the regions of 400–4000 cm−1 and 50–4000 cm−1, respectively. The UV absorption spectra of the compound that dissolved in ethanol and water solution were recorded in the range of 190–400 nm. Potential energy curve was computed by means of scanning NCC► The spectroscopic properties of para-amino hippuric acid were examined by FT-IR, FT-Raman and UV techniques and DFT/B3LYP method. ► The complete assignments are performed on the basis of the total energy distribution (TED). ► HOMO and LUMO energies, absorption wavelength and excitation energies were calculated. ► Polarizability and first hyperpolarizability of para-amino hippuric acid were calculated. ► Thermodynamic properties and their correlations with temperature were obtained from the theoretical vibrations.
Tetrahedron, 2006
The ability of the binary complex pyrene (Py)/heptakis-(6-amino)-(6-deoxy)-b-cyclodextrin (am-b-CD) to act as a chiral selector was tested at two pH values (8.0 and 9.0). Phenylalanine (Phe), methionine (Met) and histidine (His) were used as chiral model molecules. The stability of ternary complexes Py/am-b-CD/amino acid was determined by means of spectrofluorimetric measurements. The data collected showed an increase in stability going from the binary to ternary complex and above all the possibility to use the binary complex as a chiral selector. Finally, data collected at two pH values showed that the binary complex is a better chiral selector when charged rather than in its neutral form. q
Spectrofluorometric analytical applications of cyclodextrins
Luminescence, 2014
Cyclodextrins (CDs) are a family of cyclic oligosaccharides composed of a-(1,4)-linked glucopyranose subunits. The most important feature of CDs is their ability to form inclusion complexes (host-guest complexes) with a very wide range of solid, liquid and gaseous compounds by a molecular complexation. During the last decade, a considerable number of research papers has been focused on the use of CDs to enhance fluorescence intensity of different analytes and to develop CD-induced spectrofluorimetric method. In this review, the various spectrofluorimetric methods based on host-inclusion complex are presented.
European Journal of Organic Chemistry, 2012
The synthesis of a series of β-cyclodextrin (CD) dimers in which the two macrocycle units are linked by rigid-rod phenylene-ethynylene tethers of different length and shape through the cyclodextrin secondary sides is reported. The synthesis involves Sonogashira coupling reactions for construction of the tethers and final grafting of the CD units by click chemistry. The self-aggregation of the synthesized CD dimers in aqueous medium was investigated by fluorescence spectroscopy, isothermal titration calorimetry and dynamic light scattering. Rigid-rod-tethered cyclodextrin dimers
Journal of Molecular Liquids, 2017
Inclusion Composites between β-cyclodextrin and amino acids (viz., L-Methionine, L-Proline and L-Glutamine) are established in aqueous medium. Such complexation of amino acids in aqueous medium without using any organic solvent provides great ideas in different industries. The complexes are characterized by 1 H NMR which proves the formation of inclusion complex. The interactions of β-CD with amino acids are analyzed by means of surface tension and density. Contributions of different groups of the guest molecules to the limiting apparent molar volume are determined. Additionally, the stoichiometry of the inclusion complexes is also determined to be 1:1 in all the three cases. The solid inclusion complex formations of β-CD with amino acids are confirmed by PXRD analysis.