Liquid Chromatography Chip with Low-Dispersion and Low-Pressure-Drop Turn Structure Utilizing a Distribution-Controlled Pillar Array

Abstract

To realize efficient, fast separations on pillar array columns with turns, a novel turn with low-dispersion and low-pressure-drop properties was developed. This "pillar-distribution-controlled" (PDC) turn was designed as a constant-radius turn filled with octagonal pillars that were arranged to control the linear velocity of the mobile phase in the radial direction. After the pillar positions were adjusted by computational fluid dynamics analysis, 27 mm long pillar array columns with two turns were fabricated on a 20 × 20 mm(2) silicon glass plate. The PDC turns suppressed the sample dispersion to a similar extent as the previously developed tapered turn, and the pressure drop of the newly designed turn was reduced to ∼1/6 that of the tapered turn. Moreover, the C18-modified pillar array column with the PDC turns showed good bioanalytical applicability; five fluorescently labeled amino acids were separated in only 24 s at a linear velocity of 7.5 mm/s. The developed turn structure offers the advantages of longer pillar array columns with more turns for the fast analysis of complex samples.

Preparation and evaluation of mesoporous silica layers on radially elongated pillars

“…In order to perform separations of complex mixtures, large plate numbers and therefore also sufficiently long channels are required. To this end, Tsunoda et al developed pillar-distribution-controlled turns to achieve low-dispersion and low-pressure-drop in the turns in PACs [29]. In parallel, our group introduced the approach with narrow turn channels connected to the wider separation channels with radially elongated pillars (REPs), thereby minimizing peak dispersion, however at the expense of a slightly higher pressure drop [30].…”

Development of an Automated Sample Injection System for Pillar Array Columns

“…In order to employ pillar array column in practical applications, such as the analysis of biological samples, it is necessary to secure a certain degree of flow path on a small chip. Low-dispersion turns that prevent sample diffusion have been developed, and pillar array columns with long channels were created while suppressing sample diffusion [14,15]. These long-channel pillar array columns have excellent resolution, allowing for the analysis of complex samples.…”

Retention of Fluorescent Amino Acid Derivatives in Ion-pairing Reversed-phase Liquid Chromatography

“…Pillar array columns with perfectly ordered structures can shorten separation times significantly without lessening the quality of the separation. [9][10][11][12][13][14][15][16] However, pillar array columns filled with non-porous pillars have limited retention ability since only the outer surface of the pillars is available for separation. Therefore, until now, only fluorescent derivatives of hydrophobic amino acids, such as valine (Val), phenylalanine, and tyrosine, derivatized with the flurogenic reagent, 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), were retained and separated by pillar array columns.…”