Hydrodynamic chromatography of latex blends

Abstract

The ability to characterize the size and shape distributions of broadly polydisperse analytes is a driving force in particle size analysis. Multi-detector hydrodynamic chromatography (HDC), which has previously shown promise in its ability to characterize the size and shape of monodisperse, spherical polystyrene latex standards, is applied here to include the characterization of bi-, tri-, and tetramodal latex blends and their constituents varying in size, chemistry, and compactness. The ability of multi-detector HDC to distinguish between similar-sized particles of different chemistry is realized by the coupling of a concentration-sensitive detector and two different types of light scattering detectors. The use of both multi-angle static and quasi-elastic light scattering permits for determination of two different size parameters across the elution profiles of the blends. Combining the size information obtained from both light scattering methods provides a measure of how particle compactness changes as a function of size in a latex blend. Multi-detector HDC was shown to be a rapid and precise method for characterizing particle size, shape, and their distributions of broadly polydisperse analytes.

Detection Orthogonality in Macromolecular Separations: Role of the On-Line Viscometer in Characterizing Polymers at Conditions of “Spectroscopic Invisibility”

“…Furthermore, the viscometer chromatograms show that the analytes elute in an order inversely proportional to their size (size, for linear polymers, being directly proportional to molar mass). This latter is confirmed by the larger VISC peak area of PDMS 440 versus that of PDMS 116 as, all other factors being equal, the response of the viscometer is directly proportional to molar mass (except in special cases such as homogeneous hard spheres [16], or for certain monomer and oligomer solutions, which can behave [14,15] as near-hard spheres [13] or can even possess negative viscosities [17,18]). It is further confirmed by the specific viscosities of both analytes, which are overlaid upon one another in Fig.…”

Multi-detector hydrodynamic chromatography of colloids: following in Hamish Small's footsteps

“…Packed-column HDC remains a low-resolution chromatographic technique. This can be compensated for, to a certain (very limited) extent, by the use of multiple detectors [2]. A more powerful incarnation of HDC, as regards resolution, is microcapillary HDC, where dozens of peaks can be separated during the course of one experiment [47,48].…”

“…thank you Hamish Small "HDC" stands for hydrodynamic chromatography and I, of course, knew who Hamish Small was. It took me virtually no time to reply to Hamish (according to my Outlook e-mail records, I did this within 15 min of receiving the reprint request) and to flood him with everything we had published on HDC up to that point [1,2,3,4,5,6,7,8]. The unintended humor of this was not lost on Hamish, whose reply to me began "Dear Andre, Many thanks for all the articles.…”

Possibilities and Limitations of Different Separation Techniques for the Analysis of the Protein Corona

“…Inside a capillary or a column packed with nonporous beads a hydrodynamic flow profile is developing. Since the center of mass of larger particles cannot come as close to the wall as the one of small particles, they will move in faster stream lines of the flow profile and elute first . Because the separation is only flow‐driven, a minimum of outer forces is acting on the sample, very similar to AF4.…”