High performance liquid chromatography gradient elution

DALLUGE J J, NELSON B c, THOMAS J B and SANDER L 0 (1998) Selection of column and gradient elution system for the separation of catechins in green tea using high-performance liquid chromatography , J Chromatogr A, 793, 265-74. 

Reversed-phase Cig chromatography column. Keystone Scientific Betasil, 100 x 2.0-mm i.d., 5-pm particle size, 100 A, Part No. 105-701-2-CPF TSQ 7000 LC/MS/MS system with electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) interface and gradient high-performance liquid chromatography (HPLC) unit, or equivalent Vacuum manifold for use with SPE cartridges (Varian Vac Elut 10 or equivalent)... 

Snyder, L. R., Dolan, J. W., and Gant, J. R., Gradient elution in high-performance liquid chromatography. I. Theoretical basis for reversed-phase systems, /. Chromatogr., 165, 3, 1979. 

Aguilar, M. I., Hodder, A. N., and Hearn, M. T. W., High-performance liquid chromatography of amino acids, peptides, and proteins. LXV. Studies on the optimisation of the reversed-phase gradient elution of polypeptides. Evaluation of retention relationships with (3-endorphin-related polypeptides, /. Chromatogr., 327, 115, 1985. 

Stadalius, M. A., Gold, H. S., and Snyder, L. R., Optimization model for the gradient elution separation of petide mixtures by reversed-phase high-performance liquid chromatography. Verification of retention relationships, /. Chromatogr. 296, 31, 1984. 

Berchtold, M. W., Heizmann, C. W., and Wilson, K. J., Ca2+-binding proteins a comparative study of their behavior during high-performance liquid chromatography using gradient elution in reverse-phase supports, Anal. Biochem., 129, 120, 1983. 

Stoll, D.R., Cohen, J.D., Carr, P.W. (2006). Fast, comprehensive online two-dimensional high performance liquid chromatography through the use of high temperature ultra-fast gradient elution reversed-phase hquid chromatography. J. Chromatogr. A 1122 (1-2), 123-137. 

Y. Ito, T. Takeuchi, D. Ishii, M. Goto and T. Mizuno, Direct coupling of micro high performance liquid chromatography with fast atom bombardment mass spectrometry. II Application to gradient elution of bile acids, J. Chromatogr., 385 (1986) 201-209. 

High-performance liquid chromatography (HPLC) techniques are widely used for separation of phenolic compounds. Both reverse- and normal-phase HPLC methods have been used to separate and quantify PAs but have enjoyed only limited success. In reverse-phase HPLC, PAs smaller than trimers are well separated, while higher oligomers and polymers are co-eluted as a broad unresolved peak [8,13,37]. For our reverse-phase analyses, HPLC separation was achieved using a reverse phase. Cl8, 5 (Jtm 4.6 X 250 mm column (J. T. Baker, http //www.mallbaker.com/). Samples were eluted with a water/acetonitrile gradient, 95 5 to 30 70 in 65 min, at a flow rate of 0.8 mL/min. The water was adjusted with acetic acid to a final concentration of 0.1%. All mass spectra were acquired using a Bruker Esquire LC-MS equipped with an electrospray ionization source in the positive mode. 

Figure 4. High performance liquid chromatography of the octapeptide HRP-25 (Ac-Thr-Pro-Pro-Cys-Pro-Ser-Pro-Ser-NH2) on ODS (1.0 X 25 cm) using acetonitrile with a gradient of 0.1% TfaOH. Absorption at 220 nM (top) and u-v spectra (bottom) taken during the beginning and end of the elution of the dimer are shown. Constancy of the ratio of the spectra indicates homogeneity of peptide in the peak.

Figure 9.3 Schematic illustration of the electrophoretic transfer of proteins in the chromatophoresis process. After being eluted from the HPLC column, the proteins were reduced with /3-mercaptoethanol in the protein reaction system (PRS), and then deposited onto the polyacrylamide gradient gel. (PRC, protein reaction cocktail). Reprinted from Journal of Chromatography, 443, W. G. Burton et al., Separation of proteins by reversed-phase high-performance liquid chromatography , pp 363-379, copyright 1988, with permission from Elsevier Science.

High-performance liquid chromatography on silica is recommended470 for the separation of some, but not all, mixtures of ergot alkaloids an improved procedure, which is claimed to be satisfactory for the separation and determination of mixtures of cyclol ergot alkaloids obtained from fermentation media, involves the use of silica gel modified with alkylamines as the stationary phase, with gradient elution by diethyl ether-ethanol mixtures.476... 

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