共查询到20条相似文献,搜索用时 15 毫秒
1.
A thin-layer chromatographic (TLC) procedure has been developed for the determination of astemizole in plasma as the free and as protein-bound substance. The detection and quantification were performed without using internal standards. In earlier described methods for the estimation of astemizole by high-performance liquid chromatography and radioimmunoassay, only free levels in plasma were quantified, at 3.3% of the total astemizole, with the remaining 96.7% bound to plasma protein and tissue. Our method employs proteolysis of plasma proteins by incubating plasma for 2 h in pepsin. After proteolysis the astemizole is extracted, and a known amount of the extract is spotted on precoated silica gel F 254 plates. Astemizole was quantified using a Shimadzu CS-930 dual-wavelength TLC scanner. The method provides a direct estimate of total astemizole present in the plasma. 相似文献
2.
The analytical potential of a closed flow-injection system with multidetection by a single detector (for calculation of rate constants, reaction rate, dilution and amplification methods, etc.) is extended to simultaneous determinations for chromium speciation, with injection of the reagent(s) into the sample solution (which acts as the carrier). 相似文献
3.
Sklenářová H Pávek P Satı́nský D Solich P Karlı́ček R Staud F Fendrich Z 《Talanta》2002,58(6):1145-1149
The sequential injection (SIA) technique was applied in pharmacokinetic studies of the transporter-mediated passage of a model substrate, rhodamine 123 (Rho123), through the dually perfused rat term placenta. The method described was used for real-time monitoring of Rho123 concentrations in both the maternal and fetal compartments. Determination was processed by fluorescence detection (λex=480 nm, λem580 nm); calibration curve was linear over the range 0.01–50 μmol l−1 (r=0.99965), detection limit was 10 nmol l−1 (3σ) and RSD2% (10 readings). Transport of Rho123 was scanned under various conditions (ATP-synthesis inhibition) and several inhibitors of P-glycoprotein transporter were tested (e.g. quinidine). The advantages of the modern SIA method—an automated analytical tool providing both fast and precise analysis—were successfully demonstrated for examination of transport profiles to investigate the effect of P-glycoprotein on the placental transfer of Rho123. 相似文献
4.
High performance liquid chromatography has been the most popular choice for the determination of atorvastatin. In this study, two-step isocratic chromatography on silica gel 60F254 HPTLC layer and densitometric quantitation at λ = 280 nm was developed for the separation of atorvastatin from plasma constituencies and sodium diclofenac as peak-tracer. The established HPTLC method was validated in terms of LOD/LOQ, linearity, recovery and repeatability. The calibration function of the analyte was linear in the range 101–353.5 ng zone?1 and the correlation coefficient was 0.9969. The limits of detection and quantitation were 30.3 and 101 ng zone?1. The recovery and relative standard deviation obtained from between-days analysis were 97.5–103.0 and 1.7–3.4%. 相似文献
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JPC – Journal of Planar Chromatography – Modern TLC - A sensitive high-performance thin-layer chromatographic method has been developed for analysis of oxcarbazepine (OXC) in human... 相似文献
7.
José Angel Brito Helena Teruel Stéphane Massou Montserrat Gómez 《Magnetic resonance in chemistry : MRC》2009,47(7):573-577
Oxomolybdenum(VI) complexes containing diverse ligands from an electronic and topological point of view have been analysed by means of 95Mo NMR in solution with the purpose of using this technique as a tool to study their coordination chemistry and reactivity. The relationship between the electronic density on the metal tuned by the electron‐donor ability of the coordinated ligands and the 95Mo chemical shift has been proved for mono‐ and bimetallic complexes showing a hexa‐ or hepta‐coordination around the metal centre. The different origins of the signal broadening (associated either to the symmetry of the metallic polyhedron or to the presence of isomers or to the ligand de‐coordination) have been also considered to rationalise the obtained data. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
8.
Saraf Madhusudan N. Birajdar Pramod G. Loya Punnamchand Mukherjee Siddharth A. 《平面色谱法杂志一现代薄层色谱法》2007,20(3):203-207
JPC – Journal of Planar Chromatography – Modern TLC - Epalrestat is a new drug for diabetic neuropathy. A new, simple, rapid very sensitive, and accurate high performance thin-layer... 相似文献
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JPC – Journal of Planar Chromatography – Modern TLC - 相似文献
10.
A feasible capillary zone electrophoresis (CZE) method with indirect UV and contactless conductivity detection was developed for the determination of fosfomycin, an antibiotic, in human plasma and microdialysis samples. Samples were collected from test persons during a clinical trial. The background electrolytes used consisted of 25 mM benzoic acid and 0.5 mM hexadecyltrimethylammonium bromide, adjusted with tris(hydroxymethyl)aminomethane solution to pH 6.95 for plasma, and to pH 8.05 for microdialysis samples. CZE separations of the anionic analyte were carried out with reversed electroosmotic flow directed towards the anode. The limit of detection was between 0.6 and 2 microg/mL, depending on the matrix and the detection method. No sample preparation was needed for microdialysis samples; for plasma samples, proteins were precipitated with methanol (1+2, v+v), and the supernatant was analyzed. The yield determined with spiked samples was about 100%, the reproducibility of the entire method, expressed by the RSD% of three independent determinations of fosfomycin in triplicate after spiking Ringer's solutions and plasma samples, respectively, was better than 8%. The method is thus well-suited for clinical studies for the determination of the antibiotic in biological fluids. 相似文献
11.
This paper demonstrates the potential of a two-dimensional (2D) gradient mapping technique that utilized the eigenvalue manipulating transformation (EMT) of the spectral data set. The EMT technique, by lowering the power of a set of eigenvalues associated with the original data, enhances the contributions of minor principle components (PCs). The operation converts the original spectral data set to the one with subtle differences among the responses of the system being exaggerated. Small shoulders and obscure minor features may become much more visible, because such small differentiating features are often captured only by the minor PCs enlarged by the EMT treatment. This improvement for 2D mapping is potentially very important to determine the transition temperatures, which are not readily detected in convention spectral analysis. 相似文献
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J. Escoriaza M. C. Dios-Viéitez I. F. Trocóniz M. J. Renedo D. Fos 《Chromatographia》1997,44(3-4):169-171
Summary A sensitive method was developed for the determination of temazepam in plasma using capillary gas chromatography. After the
extraction into dichloromethane-pentane (1∶1), temazepam was quantitated as its O-trimethylsilyl derivative on a capillary
column with a63Ni electron capture detector using prazepam as internal standard. The detector response was found to be linear in the concentration
range 0.031 to 8 μg mL−1. The detection limit was about 3.5 ng mL−1. The intraday and inter-day coefficients of variation were below 9%. The method was used to determine the pharmacokinetic
profile of temazepam in rats after intravenous administration. 相似文献
13.
A high-performance liquid chromatographic method with UV detection (226 nm) for the analysis of sulpiride and sultopride in body fluids has been developed. Plasma, red blood cell (RBC) and urine samples were extracted by chloroform at pH 10. Internal standards were a new substituted benzamide (N-[(ethyl-1-pyrrolidinyl-2)methyl] methoxy-2-ethylsulphonyl-5-benzamide, DAN) for the sulpiride assay and sulpiride for the sultopride assay. The detection limit in plasma and RBC was 10 ng/ml for sulpiride and 15 ng/ml for sultopride. The proposed techniques were selective, reliable and sensitive enough to be used for pharmacokinetic studies and drug monitoring. Some plasma and RBC data from pharmacokinetic studies in healthy volunteers (sulpiride) or patients (sultopride) are presented. Half-lives determined from either plasma or RBC concentrations were similar (7 h for sulpiride and 5 h for sultopride). 相似文献
14.
Separation of enantiomers has become a well-established technique in many fields of science over the last decade. Unfortunately, even though there are a large number of chiral stationary phases able to perform enantiomeric separation, there is still a great deal of trial and error in developing a method for the separation of enantiomers. Thin-layer chromatography is a very versatile technique, which has brought much advancement in various fields of science. The simplicity of the technique makes it amenable for separation of enantiomers. This paper will present a review of the literature concerning separation of enantiomers. Because of the process of trial and error present in developing a chiral separation method, this paper also presents the mechanism underlying each form of separation. Thus, the methods are presented according to the main mechanism governing the particular separation. 相似文献
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Rózylo JK Zabinska A Matysiak J Niewiadomy A 《Journal of chromatographic science》2002,40(10):581-584
In this study two high-performance methods [overpressured layer chromatography (OPLC) and high-performance thin-layer chromatograpy (HPTLC) under reversed-phase conditions] are used to evaluate the hydrophobicity properties of newly synthesized bioactive compounds. The retention behavior of 24 2-(2,4-dihydroxyphenyl)benzothiazoles are examined for acquisition of log k data. With water-methanol mixtures as the mobile phases, the concentration range in which the correlation between log k and methanol content is linear is established for both methods and used to determine the hydrophobicity parameters of log kw by linear extrapolation. The effect of substituents on retention constants is quantitated by using the group contribution parameters (tauw). The results suggest the use of OPLC methods for quick analysis of physicochemical properties of a large number of organic compounds. 相似文献
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JPC – Journal of Planar Chromatography – Modern TLC - A rapid, sensitive, and eco-friendly micellar high-performance thin-layer chromatography (HPTLC) technique for the simultaneous... 相似文献
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JPC – Journal of Planar Chromatography – Modern TLC - Ethyl 8-oxo-5,6,7,8-tetrahydrothiazolo[3,2-a][1,3]diazepin-3-carboxylate (HIE-124) is one of a new generation of ultra-short-acting... 相似文献
20.
S. Perez-Olivan C. Solans M. A. García I. Pinilla F. Honrubia M. A. Bregante 《Chromatographia》2000,51(1-2):25-28
Summary A sensitive HPLC assay for the determination of grepafloxacin (GRE) in biological samples is described. Sample preparations
were carried out by adding phosphate buffer (pH 7.4, 0.1M), followed by extraction with trichloromethane. GRE and the internal
standard, enrofloxacin (ENR), were separated on a reversed-phase column using an aqueous phosphate solution-acetonitrile (78∶22)
mobile phase. The concentrations of ENR and GRE eluting of the column with retention times of 2.55, and 4.90 min, respectively
were monitored by fluorescence atλ
ex 338 andλ
em 425 nm. The method was shown to be linear from 5 to 4000 ng mL−1. The detection and quantitation limits were 5 and 10 ng mL−1, respectively. Mean recovery was determined as 90%. Inter- and intra-assay precisions were 3.0% and 3.5% respectively. The
method was applied to the determination of GRE in plasma samples collected during clinical pharmacokinetic studies. 相似文献