High-performance liquid chromatography phase selection

Selectivity of chromatographic separation is known to be varied by changing both the nonstationary phase composition and adsorbent nature. It is shown that the less are the values of the reached selectivity coefficient the higher are the requirements to column effectiveness. In this connection the choice of stationai y phase with high and predicted selectivity coefficient for the compounds being separated is still remains a topical problem of high-performance liquid chromatography. 

B. Waiczak, L. Morin-Allory, M. Chrdtien, M. Lafosse and M. Dreux, Factor analysis and experiment design in high-performance liquid chromatography. III. Influence of mobile phase modifications on the selectivity of chalcones on a diol stationary phase. Chemom. Intell. Lab. Syst., I (1986) 79-90. 

High-performance liquid chromatography (HPLC) with a micellar mobile phase or with a selective pre-column or reaction detection system has also been used to determine alkylenebis(dithiocarbamaes). ° Zineb and mancozeb residues in feed were determined by ion-pair HPLC with ultraviolet (UV) detection at 272 nm. These compounds were converted to water-soluble sodium salts with ethylenediaminetetra-acetic acid (EDTA) and sodium hydroxide. The extracts were ion-pair methylated with tetrabuthylammonium hydrogensulfate (ion-pair reagent) in a chloroform-hexane solvent mixture at pH 6.5-8.S. The use of an electrochemical detector has also been reported. ... 

Jandera, P., Correlation of retention and selectivity of separation in reversed-phase high-performance liquid chromatography with interaction indices and with lipophilic and polar structural indices, J. Chromatogr. A, 656, 437, 1993. 

Snyder L. R., Changing reversed-phase high performance liquid chromatography selectivity which variables should be tried first , ]. Chromatogr. B, 689(1), 105, 1997. 

High performance liquid chromatography-mass spectrometric methods Nitin et al. [75] developed and validated a sensitive and selective liquid chromatography-tandem mass spectrometric method (LC MS MS) for the simultaneous estimation of bulaquine and its metabolites primaquine in monkey plasma. The mobile phase consisted of acetonitrile ammonium acetate buffer (20 mM, pH 6) (50 50, v/v) at a flow rate of 1 mL/min. The chromatographic separations were achieved on two Spheri cyano columns (5 pm, 30 cm x 4.6 mm), connected in... 

Identification and quantification of natural dyes need high performance analytical techniques, appropriate for the analysis of materials of complicated matrices containing a small amount of coloured substances. This requirement perfectly fits coupling of modern separation modules (usually high performance liquid chromatography in reversed phase mode, RPLC, but also capillary electrophoresis, CE) with selective detection units (mainly mass spectrometer). 

Modern high-performance liquid chromatography has been developed to a very high level of performance by the introduction of selective stationary phases of small particle sizes, resulting in efficient columns with large plate numbers per litre. 

W. Andlauer, MJ. Martena and P. Furst, Determination of selected phytochemicals by reversed-phase high-performance liquid chromatography combined with ultraviolet and mass spectrometric detection. J. Chromatogr.A 849 (1999) 341-348. 

Bosakova, Z., Cufinovd, E., and Tes ovd, E., Comparison of vancomycin-based stationary phases with different chiral selector coverage for enantioselective separation of selected drugs in high-performance liquid chromatography, J. Chromatogr. A, 1088, 94, 2005. 

Nogueira, R., Lubda, D., Leitner, A., Bicker, W, Maier, N.M., Lammerhofer, M., and Lindner, W, Silica-based monohthic columns with mixed-mode reversed-phase/weak anion-exchange selectivity principle for high-performance liquid chromatography, J. Sep. ScL, 29, 966, 2006. 

Neubecker TA, Coombs MA, Quijano M, O Neill TP, Cruze CA, et al. 1998. Rapid and selective method for norepinephrine in rat urine using reversed-phase ion-pair high-performance liquid chromatography-tandem mass spectrometry. J Chromatogr B Biomed Sci Appl 718 225. 

Paschke, A., Neitzel, P.E., Walther, W., and Schiirmann, G. Octanol/water partition coefficient of selected herbicides determination using shake-flask method and reversed-phase high-performance liquid chromatography, J. Chem. Eng. Data, 49(6) 1639-1642, 2004. 

Walczak, B., Chretien, J.R., Dreux, M., Morin-Allory, L., and Lafosse, M. (1987), Factor Analysis and Experiment Design in High-performance Liquid Chromatography. IV. Influence of Mobile Phase Modifications of the Selectivity of Chalcones on an ODS Stationary Phase, Chemom. Intel. Lab. Sys., 1, 177-189. 

High Performance Liquid Chromatography High Performance Liquid Chromatography (HPLC) is an analytical chemical method which is used on a large scale routinely. If an HPLC method is developed, the question arises whether the analytical results from this method depend critically on small deviations in the mobile phase composition, the selected UV-wavelength for detection etc. 

Stepnowski, P. and Mrozik, W., Analysis of selected ionic liquid cations by ion exchange chromatography and reversed-phase high performance liquid chromatography, /. Sep. Sci, 28,149-154, 2005. 

A review of the literature available that will help analysts to select alternative solvents, with particular emphasis on solvent extraction and liquid chromatography, has been done. Methods of classifying solvents are discussed and tables of solvent properties are given. Strategies for optimizing mobile phases for high-performance liquid chromatography are described in detail (Barwick, 1997). 

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