Efficiency of multicapillary columns

Chip-Based Multicapillary Column with Maximal Interconnectivity to Combine Maximum Efficiency and Maximum Loadability

“…8 Coupling multiple capillaries in parallel is the obvious way out of this, but this solution has never been very successful. 9,10 One of the reasons is of a fundamental nature and is generally referred to as the polydispersity effect, describing how the lack of channel-interconnectivity between channels can easily lead to a dramatic extra dispersion due to the inevitable small channel-to-channel differences in migration velocity. 11,12 Inspired by the seminal Regnier paper 13 and focusing on the area of liquid chromatography, our group has in the past years shown that it is possible to produce packed bed columns that have a much lower eddy-dispersion than the traditional packed bed of spheres.…”

“…The novelty of the REP approach is that, with the proper spatial arrangement, the chip has the potential to act as the ideal multicapillary GC system, i.e., providing the same efficiency as a single open-tubular capillary and not suffering from any differences in channel-to-channel diameter, which strongly plagues the conventional multicapillary systems. 9,10 In the present study, we describe the design of a REP column that is optimized for GC, estimated the extra-column contributions to band broadening, and determined the efficiency before and after coating the column with a retentive PDMS polymer layer. Given we worked with relatively small silicon wafers (4 in., offering a useable circular working space with a diameter of 8 cm), while still trying to achieve a considerable column length (among others to avoid extracolumn effects), the column was designed as a serpentine channel with a total length of 70 cm, consisting of 10 segments connected by turns preceded by fluid distributors/collectors (Figure 1a).…”

“…Volumetric loadability in GC is, for example, a limiting factor in the analysis of very volatile components (air quality monitoring) or in the analysis of ultratrace compounds in the presence of major interfering solutes. − Similar problems arise, for example, in the metabolomics area, where the pursued biomarkers are often only present in very low concentrations (ng/L level and lower) together with, e.g., common fatty acids expressed at very high concentrations . Coupling multiple capillaries in parallel is the obvious way out of this, but this solution has never been very successful. , One of the reasons is of a fundamental nature and is generally referred to as the polydispersity effect, describing how the lack of channel-interconnectivity between channels can easily lead to a dramatic extra dispersion due to the inevitable small channel-to-channel differences in migration velocity. , …”

“…Whereas these studies used pillars with a square or circular cross-section, we believe this is the first study wherein the use of REPs in GC has been investigated. The novelty of the REP approach is that, with the proper spatial arrangement, the chip has the potential to act as the ideal multicapillary GC system, i.e., providing the same efficiency as a single open-tubular capillary and not suffering from any differences in channel-to-channel diameter, which strongly plagues the conventional multicapillary systems. , …”

Использование Золь-Гель Метода При Нанесении Полиэтиленгликоля На Поликапиллярные Колонки

“…Нанесение НФ на МКТ осуществляли статическим методом низкого давления коррелированным образом, при котором в капилляры большего диаметра вносится большее количество неподвижной фазы, что позволяет существенно увеличить эффективность получаемых ПКК [28,29].…”