In present study, an investigation was carried out to develop and validate an analytical method for the selective extraction and determination of griseofulvin (GSF) from plasma samples. For this purpose, a rational approach was made to synthesize and characterize the surface molecularly imprinted polymers (SMIPs). The SMIPs were utilized as solid phase extraction (SPE) sorbents. The SMIPs were prepared by using GSF as template molecule on the surface of modified silica particles through a non-covalent technique. The particles demonstrated high adsorption capacity (119.1 µg/mL), fast adsorption equilibrium time (30 min) and good recognition selectivity for the template drug. The scanning electron microscopy and infrared spectroscopy were used to explain the structural and morphological characteristics of the SMIPs and surface non-imprinted polymers. The SPE method was combined with HPLC for plasma analysis. The method validation results demonstrated that the established method possessed good linearity for GSF ranging from 0.1 to 50 µg/mL (R2 = 0.997). The limit of detection for this method was 0.02 µg/mL for rat plasma samples. The recoveries of GSF from spiked plasma samples were (90.7–97.7%) and relative standard deviations were (0.9–4.5%). Moreover, the SMIPs as selective SPE sorbent can be reused more than 8 times which is a clear advantage over commercial SPE sorbents. Finally, the usefulness of the proposed strategy was assessed by extraction and detection of GSF in real rat plasma samples. 相似文献
A continuously scanning Michelson interferometer was developed to modulate an intensive light source spectrally. The interferogram is used as a stimulus to investigate spectral sensitivities in insects and man. The FIS-method is fast and precise and shows many advantages which are partly based on the advantages of Fourier spectroscopy. The existing applications are summarized. 相似文献
The principles underlying a novel method intended for analyzing experimental data obtained when studying fluctuation processes are considered. The method in question is Chebyshev’s spectroscopy. The application of this method allows one to determine statistic characteristics of steady-state electrochemical noise against the background of severe deterministic interference without invoking the procedure of the fitting of the initial data. The potentialities of this novel method, which is intended for treating noise experiment, are demonstrated by examining model examples and analyzing the electrochemical noise generated by a lithium electrode placed in an aprotic organic electrolyte. 相似文献
Mass spectrometry (MS) is extensively used for the identification and sequencing of nucleic acids but has so far seen limited
use for characterization of their higher order structures. Here, we have applied a range of different tandem mass spectrometry
techniques, including electron detachment dissociation (EDD), infrared multiphoton dissociation (IRMPD), activated ion (AI)
EDD, and EDD/IRMPD MS3, in a Fourier transform ion cyclotron resonance mass spectrometer to the characterization of three isomeric 15mer DNAs with
different sequences and predicted solution-phase structures. Our goal was to explore whether their structural differences
could be directly probed with these techniques. We found that all three 15mers had higher order structures in the gas phase,
although preferred structures were predicted for only two of them in solution. Nevertheless, EDD, AI EDD, and EDD/IRMPD MS3 experiments yielded different cleavage patterns with less backbone fragmentation for the more stable solution-phase structure
than for the other two 15mers. By contrast, no major differences were observed in IRMPD, although the extent of backbone cleavage
was higher with that technique for all three 15mers. Thus, experiments utilizing the radical ion chemistry of EDD can provide
complementary structural information compared to traditional slow heating methods, such as IRMPD, for structured nucleic acids. 相似文献
Two vibrational spectrometry-based methodologies were developed for Metamitron determination in pesticide formulations. Fourier transform-middle infrared (FT-MIR) procedure was based on the extraction of Metamitron by CHCl3 and latter determination by peak area measurement between 1556 and 1533 cm−1, corrected with a two points baseline established from 1572 to 1514 cm−1. Fourier transform-near infrared (FT-NIR) determination was made after the extraction of Metamitron in acetonitrile and measuring the peak area between 6434 and 6394 cm−1 corrected using a two points baseline defined between 6555 and 6228 cm−1. Repeatability, as relative standard deviation, of 5 independent measurements at mg g−1 concentration level, of 0.16% and 0.07% for MIR and NIR and a limit of detection of 0.03 and 0.004 mg g−1 were obtained for MIR and NIR, respectively.NIR determination provides a sample frequency of 120 h−1, higher than that found by MIR and liquid chromatographic methods (60 and 15 h−1, respectively). On the other hand, the NIR method reduces the solvent consumption and waste generation, to only 1 ml acetonitrile per sample as compared with 3.4 ml chloroform required for the MIR determination and 60 ml acetonitrile used in the chromatographic reference procedure. So, vibrational procedures can be considered serious alternatives to long and time consuming chromatographic methods usually recommended for quality control of commercially available pesticide formulations. 相似文献
The nature of a very high-dimensional chaotic attractor in an infinite-dimensional phase space is examined for the purpose of studying the relationships between the physical processes occurring in the real space and the characteristics of high-dimensional attractor in the phase space. We introduce two complementary bases from which the attractor is observed, one the Lyapunov basis composed of the Lyapunov vectors and the another the Fourier basis composed of the Fourier modes. We introduce the exterior subspaces on the basis of the Lyapunov vectors and observe the chaotic motion projected onto these exteriors. It is shown that a certain statistical property of the projected motion changes markedly as the exterior subspace goes out of the attractor. The origin of such a phenomenon is attributed to more fundamental features of our attractor, which become manifest when the attractor is observed from the Lyapunov basis. A counterpart of the phenomenon can be observed also on the Fourier basis because there is a statistical one-to-one correspondence between the Lyapunov vectors and the Fourier modes. In particular, a statistical property of the high-pass filtered time series reflects clearly the difference between the interior and the exterior of the attractor. 相似文献
IR spectroscopy was coupled with the matrix isolation technique to study the molecular complex formed between C3O2 and HCl and its photodissociation. The vibrational frequencies of the complex were compared with those of HCl and C3O2 monomers. For C3O2, a bent structure was characterized in the solid environment.
The vibrational frequencies were calculated in the 4000–400 cm−1 range using an ab initio method at the MP2/6-31G** level for the most stable complex; these frequencies describe the hydrogen interaction with the central carbon atom of C3O2 (T complex). The measured shifts between the vibrational mode frequencies of the complex and monomers were in good agreement with the calculated values.
Broad-band UV irradiation ( > 230 nm) of the T complex leads preferentially to ketene chloride and carbon monoxide. Ketene chloride formation can be explained by the reaction between HCl and the carbene C2O, which results from photo-dissociation at the C=CO bond of C3O2. 相似文献