Computerized optimization of RP-HPLC separation with nonaqueous or partially aqueous mobile phases

Heinisch, Sabine; Lesellier, Éric; Podevin, C.; Rocca, Jean‐Louis; Tchapla, Alain

doi:10.1007/bf02466747

Cited by 46 publications

(17 citation statements)

References 13 publications

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“…However, it is apparent that not all analysts are realizing the potential of the technique. A series of pap e rs from the lab o rat o ry of T ch apla has demonstrated that columns of the octadecylsilyl type with a high carbon load, with acetonitri l e -d i ch l o romethane mixtures as mobile phase, are capable of giving the best results, e s p e c i a l ly when optimized by ch e m o m e t rics methodology [44][45][46]. The nature of the separation is well known, i.e.…”

Section: Reversed-phase High-performance Liquid Chromatographymentioning

confidence: 99%

Some recent advances in the chromatographic analysis of lipids

Christie¹

1998

Analusis

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Procedures for structural analysis of fatty acids and high-performance liquid chromatographic (silver ion, adsorption, reversed-phase and chiral) analysis of lipids are in the forefront of developments. Supercritical-fluid chromatography is making a lesser impact.A ny selection of the most interesting and va l u abl e a dvances in the ch ro m at ographic analysis of lipids over the last few ye a rs must be a subjective one, conditioned by the ex p e rience of the author. With this caveat, I suggest that procedures for structural analysis of fatty acids must be high on any list, and those involving gas chromatography-mass spectrometry in particular. Similarly, m e t h o d o l ogy involving high-perfo rmance liquid ch ro m at ography (HPLC) has been developing apace, especially in the area of silver ion chromatography, lipid class analysis and molecular species analysis. The increasing use of evaporative light-scattering detection has greatly assisted with the last. With such instruments, the mobile phase coming from the end of the HPLC column is evaporated in a stream of air in a heated chamber; the solute does not evaporate, but is nebulized and carried as minute droplets through a light beam, which is reflected and refracted. The amount of scattered light is measured by a photomultiplier tube and bears a relationship to the concentration of material eluted from the column. In that they will respond to any lipid that does not evaporate before passing through the light beam, such There has also been a great deal of interest in the application of supercritical-fluid chromatography to the analysis of lipids. However, in my opinion, there is still little that can be done by this technique that is not better accomplished by GC or HPLC. A comprehensive r eview of this methodology has also appeared [2]. Structural analysis of fatty acidsThe potential of mass spectrometry for identification of fatty acids of natural origin has been evident for many years, but there were few reports of structural analyses on real samples as opposed to model compounds until re l at ive ly re c e n t ly. The problem has been largely solved by the use of specific amide or ester derivatives, which following ionization in the mass spectrometer stabilize the charge on a nitrogen atom remote from the structural features of interest. Radical-induced cleavage predominates in the aliphatic chain and distinctive fragmentations are achieved according to the position of double bonds, b ra n ch-points or ring stru c t u res. In p a rt i c u l a r, the use fi rst of py rro l i d e, and subsequently of picolinyl ester or 2-alkenyl-4,4-dimethyloxazoline (DMOX) derivatives, of fatty acids permits GC-MS to be employed for the separation and characterisation of these compounds from natural lipids. The technique has been aided by the ava i l ability of improved cap i l l a ry columns. Indeed, s u ch derivatives only began to be used widely when GC columns of fused silica became available, although initially it was only possible to use non-polar stationary ph...

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Section: Reversed-phase High-performance Liquid Chromatographymentioning

confidence: 99%

Some recent advances in the chromatographic analysis of lipids

Christie¹

1998

Analusis

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“…Gridding experiments refer to the repeated separation of a sample mixture while varying two or more variables in small steps [36]. Computer-based programs of this kind are PRISMA, "Osiris" and Turbo Method Development [37,38]. The results of the programs are illustrated after the calculations as triangular resolution maps.…”

Section: Computer-assisted Mobile Phase Optimization In Hplcmentioning

confidence: 99%

Natural Products in the Process of Finding New Drug Candidates

Vuorela¹,

Leinonen²,

Saikku³

et al. 2004

CMC

282

187

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Natural derived or originated compounds still play a major role as drugs, and as lead structures for the development of synthetic molecules. About 50% of the drugs introduced to the market during the last 20 years are derived directly or indirectly from small biogenic molecules. In the future, natural products will continue to play a major role as active substances, model molecules for the discovery and validation of drug targets. A multidisciplinary approach to drug discovery involving the generation of truly novel molecular diversity from natural product sources, combined with total and combinatorial synthetic methodologies provides the best solution to increase the productivity in drug discovery and development. Screening for new drugs in plants implies the screening of extracts for the presence of novel compounds and an investigation of their biological activities. It is currently estimated that approximately 420,000 plant species exist in nature. For the purpose of lead discovery, or for the scientific validation of a traditional medicinal plant or a phytopharmaceutical, active principals in complex matrices need to be identified. Therefore, the interfacing of biological and chemical assessment becomes the critical issue. Drug discovery from plants can be guided by epidemiologic studies facilitated with computer assisted HPLC microfractionation and microplate technology. Epidemiologic studies have shown that high dietary flavonoid intake may be associated with decreased risk for cardiovascular disease. Chlamydia pneumoniae is a common human pathogen and epidemiological and clinical studies have shown a connection between chronic C. pneumoniae infection, atherosclerosis and the risk of myocardial infarction. We will present here the detection of natural compounds active against C. pneumoniae as an example.

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“…The mobile phase pH was optimized for solute k values within the interval bounded by krnin = 0.5 and kmax = I5. The minimum resolution, Rsmin [15], was then determined from the retention times calculated by the proposed method for any values of pH. (Figure 3) shows that any pH value within the range 3.45-3.78 will lead to a resolution value > 1.5 for all solute pairs.…”

Section: Ph Optimization: Prediction and Verificationmentioning

confidence: 99%

“…The response surface and the simulated chromatogram were calculated using "Osiris" software [15] supplied by Datalys (Valence, France).…”

Section: Softwarementioning

confidence: 99%

Retention and column efficiency in reversed phase liquid chromatography as a function of pH for optimization purposes

1998

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Key WordsColumn liquid chromatography Chromatographic behavior pH optimization SummaryThe effects of pH on both the solute retention and the peak shape of ionogenic compounds are studied in order to propose accurate models for pH optimization purposes. Several mathematical models (theoretical and empirical) for describing the variation of the retention factor versus pH are compared within different pH ranges. Limits of such models used for optimizing the pH by requiring only 3 preliminary experimental runs, are discussed in terms of deviations (< + 5 %) of predicted retention times from experimental retention times. An original procedure is developed for selecting the most convenient retention model, from a given set of three retention data. This set is also applied to modeling the variation of both peak width and peak asymmetry with mobile phase pH conditions. Such a procedure is demonstrated as helpful for the separation of ionogenic solutes by considering mobile phase pH as an additional variable that can be useful during optimization procedures.

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Computerized optimization of RP-HPLC separation with nonaqueous or partially aqueous mobile phases

Cited by 46 publications

References 13 publications

Some recent advances in the chromatographic analysis of lipids

Some recent advances in the chromatographic analysis of lipids

Natural Products in the Process of Finding New Drug Candidates

Retention and column efficiency in reversed phase liquid chromatography as a function of pH for optimization purposes

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