Integration of a microextraction system: Solvent extraction of a Co–2-nitroso-5-dimethylaminophenol complex on a microchip

A newly designed microchannel for solvent extraction was fabricated in a quartz glass chip and applied to solvent extraction of a Co–2-nitroso-5-dimethylaminophenol complex. The aqueous solution of Co complex and toluene were introduced into the microchannel, and the Co complex extracted in toluene was detected by thermal lens microscopy (TLM). The Co complex was quickly extracted into toluene when the flow was stopped. The observed extraction time, ca. 50 s, was almost equivalent to the value calculated using the diffusion distance and diffusion coefficient. The dependence of the TLM signal on the concentration of the Co complex showed good linearity in the range of 1·10−7–1·10−6 M.