A deep microfluidic absorbance detection cell replicated from a thickly stacked SU-8 dry film resist mold

Daisuke Onoshima, Jun Wang, Michihiko Aki, Kenji Arinaga, Noritada Kaji, Manabu Tokeshi, Shozo Fujita, Naoki Yokoyama, Yoshinobu Baba

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Dry film resist SU-8 was used to make a thick mold for soft lithography of a poly(dimethylsiloxane) (PDMS) microfluidic chip with deep channels. The stacking of the SU-8 film enabled an ultra-thick (up to 500 μm) resist process on Si wafer. This process was fast and highly reproducible compared with the conventional liquid SU-8 process. The deep channel in the PDMS chip was utilized as a micro-flow cell for sensitive absorbance measurement. Sunset Yellow FCF dye was used to demonstrate absorption spectroscopy in the deep channel. Since the channel depth was proportional to the optical path length, which was proportional to the absorbance value, the PDMS chip achieved a detection limit (15.9 μM) comparable to U- or Z-shaped microfabricated absorbance detection cells in glass. Calibration curves for different solution concentrations were obtained with good R2 values (∼1).

Original languageEnglish
Pages (from-to)4368-4372
Number of pages5
JournalAnalytical Methods
Volume4
Issue number12
DOIs
Publication statusPublished - Dec 1 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Chemical Engineering(all)
  • Engineering(all)

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