Flow path device, nucleic acid purification method, and sample pretreatment system

Abstract

In order to remove impurities from a sample that includes nucleic acids and perform purification and treatment for purifying and recovering the nucleic acids in a highly efficient manner, the present disclosure (see fig. 9A and 9B) proposes a flow path device comprising: a purification membrane capable of recovering nucleic acids; a membrane accommodation section that is a space formed in a substrate, is connected to the flow path, and accommodates the purification membrane; and an annular resin ring press fitted into the membrane accommodation section, wherein the membrane accommodation section has a base surface formed such that the purification membrane can be installed between the upper surface and the lower surface of the substrate, the membrane accommodation section is divided with the base surface serving as a boundary into a membrane accommodation section upper part with a cylindrical shape and a membrane accommodation section lower part having a smaller diameter than the membrane accommodation section upper part, the flow path includes a first flow path that is connected with at least one valve mechanism, formed on the upper surface of the substrate, and connected to a side wall of the membrane accommodation section upper part, and a second flow path that is connected with at least one valve mechanism, formed on the lower surface of the substrate, and connected with the membrane accommodation section lower part, the resin ring has an outer diameter equal to or larger than the inner diameter of the membrane accommodation section upper part, the purification membrane is fixed between the base surface and the resin ring, the outer diameter of the press-fitted resin ring is smaller than the outer diameter of the resin ring when not accommodated in the membrane accommodation section, the inner diameter of the membrane accommodation section upper part is substantially the same as the inner diameter of the membrane accommodation section upper part when the resin ring is not accommodated in the membrane accommodation section, and the inner diameter of the membrane accommodation section upper part and the outer diameter of the press-fitted resin ring are substantially the same at least at a position where the side wall of the membrane accommodation section upper part and the press-fitted resin ring are closest to each other.