Use of Folded Micromachined Pillar Array Column with Low-Dispersion Turns for Pressure-Driven Liquid Chromatography

Abstract

In this study, we show for the first time that the separation efficiency of a pillar array column under pressure-driven liquid chromatography (LC) conditions can be improved using a separation channel with low-dispersion turns. The pillar array column was fabricated by reactive ion etching of a silicon substrate. With the low-dispersion-turn geometry, a column with a length and width of 110 mm and 400 microm, respectively, could be fabricated on a 20 x 20 mm microchip. Under nonretained conditions, the solute bands obtained for fluorescent compounds remained almost unchanged even after passing through the low-dispersion turns; however, significant skewing of the solute bands was observed in the case of constant-radius turns. Two coumarin dyes were well resolved under reversed-phase conditions, and a maximum theoretical plate number of 8000 was obtained. Successful separation of the fluorescent derivatives of six amino acids was achieved in 140 s. These results indicated that the separation efficiency of microchip chromatography could be significantly improved using a long separation channel with low-dispersion turns.

Rapid determination of amino acids in biological samples using a monolithic silica column

“…Because 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) was used as the fluorescence derivatization reagent (Watanabe and Imai 1982;Nonaka et al 2005Nonaka et al , 2006Aoyama et al 2010), this method was more sensitive than those using other fluorescent derivatization reagents. This method is useful because it requires only an ordinary HPLC system.…”

Retention and Bandwidth Predictions by Fast Gradient Elution Chromatography Using a Pillar Array Column

“…The microchip fabrication has been described in previous studies [7][8][9][10]. The 20 mm × 20 mm microchip was composed of a cross-Tesla mixer, a separation channel, and a sample channel.…”

“…In addition, pillar array columns have been utilized to separate biological compounds. Six fluorescently labeled amino acids were analyzed within 100 s by isocratic elution using the pillar array column [7,8]. Furthermore, to separate the components of complex biological samples, a gradient elution system was developed to accelerate the elution of strongly retained solutes using pressure-driven liquid chromatography (LC) on a microchip [9,10].…”

Tube Radial Distribution Chromatography on a Microchip Incorporating Microchannels with a Three-to-One Channel Confluence Point

“…Also, microfluidic analysis using capillary chromatography requires specific separation columns such as monolithic or packed channels or tubes. 14,19 Although they can improve separation performance, including resolution, they are costly, time-consuming and tedious to prepare. Miniaturization on a microchip incorporating microchannels was applied to the TRDC system, as described in our previous paper, 1 but temperature control was required for the process to be successful.…”