title: Effect of aspect ratio on chemical reactions on microchip.
abstract: Parallel two-phase laminar flow, which is formed when two solutions flow in microchannels, has been developed and has advanced unique research in the area of microchip analysis. In two-phase laminar flow, channel size has a significant effect on the efficiency of chemical reactions. However, the sizes of microchannels vary greatly in many studies. In this paper, we report on the effect of microchannel size on chemical reactions on a microchip. Aspect ratio is defined as the ratio of depth to width of a microchannel. Five microchips with different aspect ratios (from 0.50 to 2.00) were fabricated by mechanical machining. The reaction of nitrous acid and Saltzman reagent was carried out on these microchips and the absorbance was measured on-line in a capillary tube, which was attached to the outlet on the microchip. The results showed that the color reaction occurred more efficiently as the aspect ratio increased. This result is expected to be useful when determining the size of microchannels.
authors.affiliation: Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami-Ohsawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Shimizu
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Masaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Korenaga
mesh_terms: D005029:Ethylenediamines / Q000737:chemistry; D046208:Microchip Analytical Procedures; D009608:Nitrous Acid / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D013425:Sulfanilic Acids / Q000737:chemistry
chemical_list: D005029:Ethylenediamines; D010756:Phosphoric Acids; D013425:Sulfanilic Acids; C008588:N-(1-naphthyl)ethylenediamine; C030242:phosphoric acid; D009608:Nitrous Acid