Abstract: [Object] An object is to provide a sulfonated fine cellulose fiber having excellent transparency, a sulfonated pulp fiber suitable for the sulfonated fine cellulose fiber, a method for producing these fibers, and a derivative pulp containing the sulfonated pulp fiber. [Means for achieving the object] The sulfonated pulp fiber of the present invention is a pulp fiber comprising a plurality of cellulose fibers, wherein a part of hydroxyl groups of the cellulose fibers of the pulp fiber is substituted with sulfo groups, an introduction amount of sulfur attributable to the sulfo groups is adjusted to be higher than 0.42 mmol/g while maintaining a fiber shape, and a water retention value of the pulp fiber is adjusted to 150% or more. Since the sulfonated pulp fiber has a predetermined water retaining property or more while maintaining the fiber shape, the degree of flexibility in handling can be improved.

Abstract: [Object] An object is to provide a sulfonated fine cellulose fiber having excellent transparency a sulfonated pulp fiber suitable for the sulfonated fine cellulose fiber, a method for producing these fibers, and a derivative pulp containing the sulfonated pulp fiber. [Means for achieving the object] The sulfonated pulp fiber of the present invention is a pulp fiber comprising a plurality of cellulose fibers, wherein a part of hydroxyl groups of the cellulose fibers of the pulp fiber is substituted with sulfo groups, an introduction amount of sulfur attributable to the sulfo groups is adjusted to be higher than 0.42 mmol/g while maintaining a fiber shape, and a water retention value of the pulp fiber is adjusted to 150% or more. Since the sulfonated pulp fiber has a predetermined water retaining property or more while maintaining the fiber shape, the degree of flexibility in handling can be improved.

Abstract: A functional material for testing a liquid sample includes a based material in a sheet shape and a channel part provided on a mounting surface of the base material wherein the channel part is composed with water-permeable fibers having permeability, and water-impermeable fibers having impermeability. The water-permeable fibers and the water-impermeable fibers are arranged along the longitudinal direction of the channel part, forming voids wherein the voids are in a mesh structure in which one of the voids connects to another of the voids such that the empty spaces are linked from a base end to a tip end of the channel part. A thickness of the channel part is ranged from 20 ?m mm to 5 mm, and a width of the voids is ranged from 10 ?m to 200 ?m, allowing the liquid sample to move from the base end to the tip end due to capillarity.

Abstract: An analysis tool for use in optical analysis, comprising a detection unit 10 having through-holes 10h penetrating through the surface and the rear side of a base material 11, the detection unit 10 comprising, inside of the base material 11, a plurality of voids 11h that allows a liquid to pass through by capillary action and that communicate with the through-holes 10h, and the through-holes 10h being formed with a size that enables a liquid to be held by surface tension. Therefore, by irradiating the detection unit 10 with light, it is possible to obtain transmitted light L2 that has been transmitted through a liquid film Lf. By analyzing the transmitted light L2, a target component in a sample L can be appropriately quantified.

Abstract: [Object] An object is to provide a sulfonated fine cellulose fiber having excellent transparency, a sulfonated pulp fiber suitable for the sulfonated fine cellulose fiber, a method for producing these fibers, and a derivative pulp containing the sulfonated pulp fiber. [Means for achieving the object] The sulfonated pulp fiber of the present invention is a pulp fiber comprising a plurality of cellulose fibers, wherein a part of hydroxyl groups of the cellulose fibers of the pulp fiber is substituted with sulfo groups, an introduction amount of sulfur attributable to the sulfo groups is adjusted to be higher than 0.42 mmol/g while maintaining a fiber shape, and a water retention value of the pulp fiber is adjusted to 150% or more. Since the sulfonated pulp fiber has a predetermined water retaining property or more while maintaining the fiber shape, the degree of flexibility in handling can be improved.

Abstract: A functional material for testing a liquid sample includes a based material in a sheet shape and a channel part provided on a mounting surface of the base material wherein the channel part is composed with water-permeable fibers having permeability, and water-impermeable fibers having impermeability. The water-permeable fibers and the water-impermeable fibers are arranged along the longitudinal direction of the channel part, forming voids wherein the voids are in a mesh structure in which one of the voids connects to another of the voids such that the empty spaces are linked from a base end to a tip end of the channel part. A thickness of the channel part is ranged from 20 ?m mm to 5 mm, and a width of the voids is ranged from 10 ?m to 200 ?m, allowing the liquid sample to move from the base end to the tip end due to capillarity.

Abstract: Disclosed herein is a functional material having the function of detecting a predetermined substance or the like present in a sample with high accuracy even when the amount of the sample is small, and a method for producing the functional material. The functional material includes a channel part 10 that allows a liquid to pass therethrough, and the channel part 10 is made of a water-permeable material 11 containing a water-impermeable material 12. The water-impermeable material 12 is placed between pieces of the water-permeable material 11, and therefore voids 10h can be formed between the water-impermeable material 12 and the water-permeable material 11. That is, a network of the voids 10h can be formed in the channel part 10. A liquid sample supplied to the channel part 10 is allowed to move while being allowed to penetrate into the voids 10h.

Abstract: Disclosed herein is a functional material having the function of detecting a predetermined substance or the like present in a sample with high accuracy even when the amount of the sample is small, and a method for producing the functional material. The functional material includes a channel part 10 that allows a liquid to pass therethrough, and the channel part 10 is made of a water-permeable material 11 containing a water-impermeable material 12. The water-impermeable material 12 is placed between pieces of the water-permeable material 11, and therefore voids 10h can be formed between the water-impermeable material 12 and the water-permeable material 11. That is, a network of the voids 10h can be formed in the channel part 10. A liquid sample supplied to the channel part 10 is allowed to move while being allowed to penetrate into the voids 10h.