Interaction chromatography, definition

Salt Effects. The definition of a capacity factor k in hydrophobic interaction chromatography is analogous to the distribution coefficient, in gel permeation chromatography ... 

There are other novel media with characteristics similar to functionalized membranes. Some of the commercially available media are listed in Table 2. These materials in many cases are at the cross-lines of definitions and are frequently compared in the MA literature. Organic separations in the reserve-phase (RP) and hydrophobic interaction chromatography (HIC) mode are not very common on filtration-based MA materials. However, the methacrylate copolymers can be used for this purpose. Also rodlike monolithic materials enable greater flexibility in these types of chemistry.13,14 The method of Tennikova and Svec15-17 has been used to commercialize a novel disk type separation media, called CIM (Convective interaction media, BIA, Ljubljana, Slovenia).18-21 Analytical-scale separations can be performed on... 

Thermal changes resulting from solute interactions with the two phases are definitely second-order effects and, consequently, their theoretical treatment is more complex in nature. Thermal effects need to be considered, however, because heat changes can influence the peak shape, particularly in preparative chromatography, and the consequent temperature changes can also be explored for detection purposes. 

In principle, any type of sample can be analysed by SEC provided that it can be solubilised and that there are no enthalpic interactions between sample and packing material. By definition then, this technique cannot be carried out on vulcanisates and even unvulcanised fully compounded rubber samples can present problems due to filler-rubber interactions. The primary use of SEC is to determine the whole MWD of polymers and the various averages (number, viscosity, weight, z-average) based on a calibration curve and to allow qualitative comparisons of different samples. Many commercial polymers have a broad MWD leading to strong peak overlap in the chromatography of complex multicomponent systems. 

Chromatography is the separation of a mixture of compounds into its individual components based on their relative interactions with an inert matrix. However, chromatography is more than a simple technique, it is an important part of science encompassing chemistry, physical chemistry, chemical engineering, biochemistry and cutting through different fields. It is worth to be mentioned here that the lUPAC definition of chromatography is "separation of sample components after their distribution between two phases". 

Solvent interaction model for normal-phase liquid chromatography. The solvent-interaction model of Scott and co-workers (Scott and Kucera, 1979) assumes that the analyte partitions between the bulk mobile phase and a layer of solvent absorbed onto the stationary phase. The quantitative description of the relationship between retention and the composition of the mobile phase in the solvent-interaction model requires the definition of the void volume corrected retention volume (V), which is related to the retention volume (F ) and the void volume (Fq) by... 

Fig. 8-11. Proposed adsorption complex of aniline (sample) with diethylamine (solvent) as an explanation of the basic eluent anomaly. The representation of bonding between each adsorbate molecule and the alumina surface in Fig. 8-11 is not intended to imply a definite type of interaction. Reprinted from the Journal of Chromatography (12) by permission of Elsevier Publishing Company.

Solvent strength and selectivity are the properties commonly used to classify liquid stationary phases as selection tools for method development in gas chromatography [29,102-104]. Solvent strength and polarity are often used interchangeably and can cause confusion. Polarity is sometimes considered to be the capacity of a stationary phase for dipole-type interactions alone, while more generally solvent strength is defined as the capacity of a stationary phase for all possible intermolecular interactions. The latter definition is quite sensible but unworkable because there is no substance that is uniquely polar that might be used to probe the polarity of other substances. Indirect measurements of polarity, such as those scales related one way or another to the... 

Chemometrics has been defined in some texts [155] as the entire process whereby data are transformed into information used for decision-making. It is this definition that is the most applicable to separation sciences, more specifically in method development and optimisation in liquid chromatography. In this example, chemometrics has been used to predict optimum separation conditions based on empirical data and other separation information. Chemometric approaches to method development can be based on either sequential simplex models [156] or simultaneous fixed factorial designs [157] or interactive mixture designs [158] which combine the advantages of simultaneous and simplex models. 

High-performance liquid chrottHtogtaphy (HPLC), definition. 3 HlUC, 217-223 HPLC, definition, 3 Hydrodynamic chromatography, 142 Hydrolytic stability, 107,346,369-370 Hydrophilic interaction (HlUC), 5,135,136, 217-223... 

Most of the specifics of the chemistry of chromatography will be covered in the chapters dedicated to each separation mechanism. Nevertheless, a few topics, including some definitions, are sufficiently generic to be treated separately. In the following chapter, we look at the definition of the retention factor and the relative retention, and then look at the relationship of retention with the free energy of the interaction with the stationary phase. 

As regards adhesives proper only two series of studies fall in this category [9,71]. The first one of these models the process of chromatography [9]. There is no doubt that chromatography is a clear case of differential, competitive sorption, and hence a case of differential, competitive adhesion. Movement is inherent in the definition of the system, and predominance of secondary force interfacial interactions is inherent to the system too. 

The retention and the selectivity of separation in RP and NP chromatography depend primarily on the chemistry of the stationary phase and the mobile phase, which control the polarity of the separation systems. There is no generally accepted definition of polarity, but it is agreed that it includes various selective contributions of dipole-dipole, proton-donor, proton-acceptor, tt-tt electron, or electrostatic interactions. Linear Free-Energy Relationships (LFER) widely used to charactaize chemical and biochemical processes were successfiiUy apphed in liquid chromatography to describe quantitative structure-retention relationships (QSRR) and to characterize the stmctural contributions to the retention and selectivity, using multiple linear correlation, such as Eq. 

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