Micron‐sized pillars for ion‐pair reversed‐phase DNA separations

In the present paper, the feasibility to construct micron‐sized silicon pillar channels to be used in HPLC is studied. For this, a channel with flow‐through pores of 1 μm and with critical sidewall dimensions below 1 μm was constructed using advanced deep‐UV lithographic equipment. Integrating a 3‐nL injection system on the chip directly in front of the separation channel and using elongated distribution structures, a very controlled and high aspect ratio sample definition across the relatively wide separation channel was accomplished. The system was evaluated in isocratic ion‐pair RP mode, allowing the separation of a mixture of two components with, respectively, 300 and 400 base pairs in 5 s only.