Reverse-phase liquid chromatograph column

Epler, K.S. et al.. Evaluation of reversed-phase liquid chromatographic columns for recovery and selectivity of selected carotenoids, J. Chromatogr, 595, 89, 1992. 

Euerby, M. R. and Petersson, P., Chromatographic Classification and Comparison of Commercially Available Reversed-phase Liquid Chromatographic Columns Using Principal Component Analysis, /. Chromatogr. A, 994 13—36, 2003. 

Visky, D., Y. Vander Heyden, T. Ivanyi, et al. 2002. Characterisation of reversed-phase liquid chromatographic columns by chromatographic tests. Evaluation of 36 test parameters Repeatability, reproducibility and correlation. J. Chromatogr. A 977 39-58. 

Vora, Chromatography of radiolabeled anions using reversed-phase liquid chromatographic columns, J. Chromatogr., 333 269 (1985). 

E. H. Slaats, W. Markovski, J. Fekete, and H. Poppe, Distribution equilibria of solvent components in reversed-phase liquid chromatographic columns and relationship with the mobile phase volume, J. Chromatogr. 207 (1981), 299-323. 

M. R. Euerby and P. Petersson, Chromatographic classihcation and comparison of commercially available reversed-phase liquid chromatographic columns using principal component analysis, J. Chromatogr. A 994 (2003), 13-36. 

E. Van Gyseghem, M. Jimidar, R. Sneyers, D. Redlich, E. Verhoeven, D. Massart, and Y. Vander Heyden, Selection of reversed-phase liquid chromatographic columns with diverse selectivity towards the potential separation of impurities in drugs, /. Chromatogr. A 1042 (2004), 69-80. 

T. E. Boothe, A. M. Emran, R. D. Hnn, P.J. Kothari and M.M.Vora, Chromatography of radiolabeled anions using reversed-phase liquid chromatographic columns,/ Chromatogr., 333,269,1985. 

Reverse-Phase Liquid Chromatographic Columns with Temperature, Anal. Chem. 1978,50(6), 749. 

Mohammad, J, Jaderlund, B., and Lindblom, K., New polymer-based prepacked column for the reversed-phase liquid chromatographic separation of peptides over the pH range 2-12, J. Chromatogr. A, 852, 255, 1999. 

The stationary phase may be a solid or liquid on a solid support. The mechanisms responsible for distribution between phases include surface absorption, ion exchange, relative solubilities and steric affects . High performance liquid chromatography is a useful method for quinolizidine alkaloid analysis, especially when pure standards are available". This method was recently used for alkaloid metabolite extraction and analysis . A simple reversed-phase liquid chromatographic method has been developed for the simultaneous quantitation of four anticancerous alkaloids vincristine, vinblastine, and their precursors catharanthine and vindoline using a specific HPLC column . 

A reversed-phase liquid chromatographic method was developed for simultaneous determination of carboxylic acids, phenolic compounds, and SA in white wines (84). The diluted samples are injected into a Spherisorb ODS-2 column with a gradient of sulphuric acid (pH 2.5)/methanol as mobile phase. A diode array detector is used, set at 210 nm for carboxylic acids and altered to 278 nm, during the run, for phenolics and SA. The identification of compounds is based on retention time and UV spectra. Some cleanup methods (Sep-Pak C18 and an ion-exchange column) were tested and did not improve the results. The analysis was considered simple, with no sample preparation. Application of this method was illustrated by analyses of Brazilian Welchriesling wines (84). 

Metwally et al. also developed a reversed-phase liquid chromatographic method using 5-C8 (22 cm x 4.6 mm i.d. x 5 /an particle size) column for quantitation of zaleplon using acetonitrile-deionized water (35 65, v/v) as a mobile phase using paracetamol as IS and a flow rate of 1.5 ml/min with UV detection of the effluent at 232 nm at ambient temperature over a... 

J. W. Dolan, A. Maule, D. Bingley, L. Wrisley, C. C. Chan, M. Angod, C. Lunte, R. Krisko, J. M. Winston, B. A. Homeier, D. V. McCalley, and L. R. Snyder, Choosing an equivalent replacement column for a reversed-phase liquid chromatographic assay procedure, J. Chromatogr. A 1057 (2004), 59-74. 

An example for the separation for flavonoids with HP-RPC is the screening method employed for the systematic identification of glycosylated flavonoids and other phenolic compounds in plant food materials by Lin et al20 These authors used an analytical 4.6 mm x 250 mm 5 pm C18 silica column at 25 °C with linear gradient elution (eluent A (0.1% FA in water and eluent B 0.1% FA in ACN) at 1.0 ml min-1. DAD was performed at 270, 310, 350, and 520 nm to monitor the UV/VIS absorption. The LC system was directly coupled to an ESI mass spectrometer without flow splitting and the mass spectra acquired in the positive and negative ionization mode. The same analytical scheme (aqueous MeOH extraction, reversed-phase liquid chromatographic separation, and diode array and mass spectrometric detection) can be applied to a wide variety of samples and standards and therefore allows the cross-comparison of newly detected compounds in samples with standards and plant materials previously identified in the published literature. 

Sugar concentration was determined by reversed phase liquid chromatograph with a 4.6 mm( ) x 250 mm length column of Nagel Nu-cleosll 5NH2 and a 70% acetonitrile aqueous buffer solution fed at the rate of 1.5 ml/mln at 25"C. Shodex RI-SEll refractometer was used as the detector. 

Kim B-H, Lee SC, Lee HJ, Ok JH, reversed phase liquid chromatographic method for the analysis of aminoglycoside antibiotics using pre-column derivatization with phenyliso-cyanate, Biomed. Chromatogr. 2003 17 396-403. 

Hgure 1 Reversed-phase liquid chromatographic profile of a tryptic digest of bovine growth hormone on a C18 silica column, particle diameter 5 pm, average pore size 30 nm packed into 25 cm X 4.6 mm ID columns. Gradient elution was carried out from 0% to 50% acetonitrile in 0.1%TFA over 60 min at a flow rate of 1 ml min k Detection was by absorbance at 215nm. 

On the basis of findings from the preliminary investigation of the above kind in a conventional electrochemical cell, a suitable mobile phase for the reverse phase liquid chromatographic separation of Cu(dtc)2 complexes with electrochemical detection would be 70% acetonitrile-30% water (0.02 M acetate buffer) with NaNOa as supporting electrolyte. Electrodes investigated in the published paper [3] were the same as in the stationary cell and both oxidation and reduction processes for Cu(dtc)2 were compared. A Metrohm ElA 1096 detector cell (wall jet electrode) was used in this particular cell and a Cig reverse phase chromatographic column was employed. Retention volumes of 14.4 and 10.4 ml were obtained for Cu(dedtc)2 and Cu(pydtc)2, respectively. This smaller retention volume of Cu(pydtc)2 may be attributed to the more polar nature of the complexes. Other experimental details are available in reference 3. In addition, the possibility of in situ formation of the Cu(dtc)2 complex as an alternative to ex situ formation of the complex externally to the column also was examined. 

Tswett s initial column liquid chromatography method was developed, tested, and applied in two parallel modes, liquid-solid adsorption and liquid-liquid partition. Adsorption ehromatography, based on a purely physical principle of adsorption, eonsiderably outperformed its partition counterpart with mechanically coated stationary phases to become the most important liquid chromatographic method. This remains true today in thin-layer chromatography (TLC), for which silica gel is by far the major stationary phase. In column chromatography, however, reversed-phase liquid ehromatography using chemically bonded stationary phases is the most popular method. 

Turner and Warnock [56] determined miconazole in human saliva using high performance liquid chromatography. Deproteinated human saliva samples containing miconazole was chromatographed on a C8 reversed-phase radial compression column using 77% methanol in 0.01 M EDTA with 0.005 M w-nonylamine at a flow... 

The silanophilic character of 16 reversed-phase high-performance liquid chromatographic columns was evaluated with dimethyl diphenycyclam, a cyclic tetraza macrocycle [101]. The method is rapid, does not require the removal of packing material, and uses a water-miscible solvent. The results demonstrate two points first, cyclic tetraza macrocycles offer substantial benefits over currently used silanophilic agents second, the method can easily differentiate the performance of various columns in terms of their relative hydrophobic and silanophilic contributions to absolute retention. 

Normal-phase liquid chromatography is thus a steric-selective separation method. The molecular properties of steric isomers are not easily obtained and the molecular properties of optical isomers estimated by computational chemical calculation are the same. Therefore, the development of prediction methods for retention times in normal-phase liquid chromatography is difficult compared with reversed-phase liquid chromatography, where the hydrophobicity of the molecule is the predominant determinant of retention differences. When the molecular structure is known, the separation conditions in normal-phase LC can be estimated from Table 1.1, and from the solvent selectivity. A small-scale thin-layer liquid chromatographic separation is often a good tool to find a suitable eluent. When a silica gel column is used, the formation of a monolayer of water on the surface of the silica gel is an important technique. A water-saturated very non-polar solvent should be used as the base solvent, such as water-saturated w-hexane or isooctane. 

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