Hyphenated Techniques in Liquid Chromatography of Polymers

Abstract

Complex polymers are distributed in more than one direction of molecular heterogeneity. In addition to the molar mass distribution, they are frequently distributed with respect to chemical composition, functionality, and molecular architecture. For the characterization of the different types of molecular heterogeneity it is necessary to use a wide range of analytical techniques. Preferably, these techniques should be selective towards a specific type of heterogeneity. The combination of two selective analytical techniques is assumed to yield two-dimensional information on the molecular heterogeneity.The present review presents the principle ideas of combining different analytical techniques in two-dimensional analysis schemes. Most promising protocols for hyphenated techniques refer to the combination of two different chromatographic methods and the combination of chromatography and spectroscopy. This review will discuss the basic principles of two-dimensional chromatography and the hyphenation of liquid chromatography with selective detectors.

Flow-Driven Translocation of a Diblock Copolymer through a Nanopore

“…Great progress has been made in the synthesis of polymers with complex structures in the past 50 years. , However, to this day, it is still challenging to synthesize monodisperse polymers, even for linear homopolymers. − Therefore, we have been pursuing new analytical methods to characterize and purify polymers with different structures, which are essential for studying the properties and applications of these polymers. Although gel chromatography and field-flow fractionation are widely unitized to separate polymers by exploiting the depletion force produced by the interactions of a polymer with an inert sorbent surface, , the resolution of these methods is unsatisfactory. In recent years, flow-driven polymer translocation through a nanopore has attracted more attention because of its significance in the purification and separation of polymers with complex structures. − …”

Determination of Chemical Composition Distribution and Molecular Weight Distribution of Poly(2-(perfluoroalkyl)ethyl acrylate-co-alkyl acrylate) by High Performance Liquid Chromatography and Size Exclusion Chromatography

“…[16] However, as the loading mass in general NELC analysis is less than that of SEC analysis, the more practical and more prevalent order is to conduct SEC first, followed by NELC of the fractions. In addition, as shown previously, the copolymer shows a characteristic and rather sharp CCD pattern; NELC preparation 132 T. Isemura et al is expected to undermine the CCD resolution unless preparative isolation is conducted in many fractions.…”

“…Although these classifications of separation principles are in practice mixed and complex, copolymers can be separated by the combination of influences from both solubility and adsorption. [15] Moreover, OC has been developed into cross-fractionation or twodimensional chromatography, [16] that is, a combination of two separation systems of SEC and HPLC. For example, styrene-methylmethacrylate copolymer [17] and poly(styrene-vinyl acetate) block copolymers [18] have been fractionated by both SEC and LAC.…”

Mass spectra of copolymers

“…Liquid chromatography at the critical conditions (LCCC) is a relatively new LC techique, and it is ideally suited for block copolymers due to a most peculiar feature—namely, the elution time depends on the length of the first block, and is independent on the length of the second block (Pasch, 2000). The LCCC‐MALDI technique for block copolymers consists in fractionating a polymer, analyzing selected fractions, and deriving M n , M w , and the number‐average lengths of the blocks.…”