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941.
D. Labadarios I. M. Moodie J. A. Burger G. S. Shephard 《Journal of separation science》1988,11(3):229-233
A procedure is described in which a wide bore glass capillary column is used as an alternative to the more traditional packed column in the analysis of amino acid levels in plasma. The coefficients of variation for all amino acids (with the exception of aspartic acid) were better than 11% with recoveries ranging from 81% to 122%. The data are compared with the corresponding results obtained using a packed column and show significant differences (p < 0.005) between values for glycine, serine, isoleucine, proline, methionine, aspartic acid, phenylalanine, and lysine. A similar comparison between results from the wide bore and the fused-silica open tubular (FSOT) column shows better agreement. Adjustment of chromatographic conditions for the wide bore analysis yields results in good agreement with those from FSOT analysis but which still differe significantly from the backed column data. 相似文献
942.
Krystyna Srogi 《Mikrochimica acta》2006,154(3-4):191-212
This article reviews the analysis of drugs and drug metabolites in hair by chromatographic procedures, including the pretreatment
steps, and the extraction methods. The general tendency in the last years, to highly sophisticated techniques (GC–MS–NCI,
HPLC–MS, GC–MS–MS) illustrates the constant fight for sensitivity. 相似文献
943.
Boron Removal from Aqueous Solutions by Adsorption on Waste Sepiolite and Activated Waste Sepiolite Using Full Factorial Design 总被引:3,自引:0,他引:3
In the present paper, boron removal from aqueous solution by adsorption was investigated and 23 full factorial design was applied. Non activated waste sepiolite (NAWS) and HCl activated waste sepiolite (AWS) were used as adsorbents. Regression equation formulated for boron adsorption was represented as a function of response variables. The results obtained from the study on parameters showed that as pH increased and temperature decreased boron removal by adsorption increased. Adsorbed boron amount on AWS was higher than that of NAWS. Maximum boron removal was obtained at pH 10 and 20°C for both adsorbents. Adsorption data obtained from batch adsorption experiments carried out with NAWS and AWS fitted to the Langmuir equation. The batch adsorption capacities were found in mg/g: 96.15 and 178.57 for NAWS and AWS, respectively. The capacity value for column study was obtained by graphical integration as 219.01 mg/g for AWS. The Thomas and the Yoon-Nelson models were applied to experimental data to predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design. 相似文献
944.
An automated gas chromatographic subsystem for the provision of fast and reliable concentration profile data for distillation column control is presented. The subsystem consists of a gas chromatograph, equipment for sample conditioning and a PC/AT compatible computer communicating with the supervisory process computer. A fast separation time is obtained through the use of a liquid chromatographic packing material and a high pressure drop across the column. Preliminary results show separation times below 10 s for the water-methanol-isopropanol system. Peak areas are quantified by use of parameter estimation in the frequency domain, a method that does not demand complete peak separation. 相似文献
945.
Vasbinder E Van der Weken G Vander Heyden Y Baeyens WR Debunne A Remon JP García-Campaña AM 《Biomedical chromatography : BMC》2004,18(1):55-63
An ion-pair high performance liquid chromatographic method was developed for the simultaneous determination of p-aminosalicylic acid (PAS) and its degradation product m-aminophenol (MAP) in a newly developed multiparticular drug delivery system. Owing to the concentration differences of PAS and MAP, acetanilide and sulfanilic acid were used as internal standards, respectively. The separation was performed on a Chromolith SpeedROD RP-18e column, a new packing material consisting of monolithic rods of highly porous silica. The mobile phase composition was of 20 mm phosphate buffer, 20 mm tetrabutylammonium hydrogen sulphate and 16% (v/v) methanol adjusted to pH 6.8, at a flow-rate of 1.0 mL/min, resulting in a run-time of about 6 min. Detection was by UV at 233 nm. The method was validated and proved to be useful for stability testing of the new dosage form. Separation efficiency was compared between the new packing material Chromolith SpeedROD RP-18e and the conventional reversed-phase cartridge LiChroCART 125-4 (5 microm). A robustness test was carried out on both columns and different separation parameters (retention, resolution, run time, temperature) were determined. 相似文献
946.
947.
In this work, the "retention time gradient effect" of gradient GC columns is intensively studied to establish some equations and formulas for structure calculation of chromatographic columns. In addition, the relevant computer programs are designed. 相似文献
948.
The paper describes the measurement and calculation of the primary statistical errors in the evaluation of TLC or HPTLC using in situ reflectance measurements. The primary errors are the errors of the sample volume spotted onto the plate, errors caused by the chromatographic process itself, the positioning error of the plate with respect to the centre of the light beam and the error in the light measurement. By scanning the same spot, the same track or the same plate under different conditions, the various errors can be determined. 相似文献
949.
本文从理论上推导出程序柱柱效及分离度的函数关系式,并将程序柱与常规柱进行比较,理论计算和实验结果都表明正切程序柱是一种较理想的程序柱。 相似文献
950.