Abstract: A method for preparing a hydrogel that reversibly changes color depending on pH includes: (S10) dissolving a carboxyl group-containing polysaccharide in buffer to obtain a polysaccharide solution; (S20) adding a cross-linker solution composed of a mixture of an organic solvent and a cross-linker to the polysaccharide solution; (S30) adding, to the cross-linker-containing polysaccharide solution resulting from step (S20), an organic solution composed of a mixture of an organic solvent and a first organic compound containing an aromatic functional group having at least one hydroxyl group bonded thereto, to form a mixture solution, and allowing the mixture solution to react; (S40) obtaining a polymer complex from the reaction mixture resulting from step (S30); and (S50) mixing the polymer complex from step (S40) with an organic dye comprising a second organic compound containing an aromatic functional group having at least one hydroxyl group bonded thereto.

Abstract: The present invention relates to a hydrogel bead for detecting hydrofluoric acid and a kit comprising the same, and more particularly, to a hydrogel bead capable of detecting hydrofluoric acid using an organometallic ligand compound that reversibly changes color depending on the concentration of hydrofluoric acid when coming into contact with hydrofluoric acid, and to a kit for detecting hydrofluoric acid comprising the same. In an embodiment, a method for preparing a hydrogel bead for detecting hydrofluoric acid comprises the steps of: mixing an organic compound, which contains an aromatic functional group having at least one hydroxyl group bonded thereto, with a solution of a metal-ligand compound that bonds with the organic compound, thereby preparing a mixed solution; dropping the mixed solution onto a gelling agent; and adding coagulating agent to the mixture resulting from the dropping step to form a porous bead.

Abstract: A method for preparing a hydrogel that reversibly changes color depending on pH includes: (S10) dissolving a carboxyl group-containing polysaccharide in buffer to obtain a polysaccharide solution; (S20) adding a cross-linker solution composed of a mixture of an organic solvent and a cross-linker to the polysaccharide solution; (S30) adding, to the cross-linker-containing polysaccharide solution resulting from step (S20), an organic solution composed of a mixture of an organic solvent and a first organic compound containing an aromatic functional group having at least one hydroxyl group bonded thereto, to form a mixture solution, and allowing the mixture solution to react; (S40) obtaining a polymer complex from the reaction mixture resulting from step (S30); and (S50) mixing the polymer complex from step (S40) with an organic dye comprising a second organic compound containing an aromatic functional group having at least one hydroxyl group bonded thereto.

Abstract: The present invention relates to a hydrogel bead for detecting hydrofluoric acid and a kit comprising the same, and more particularly, to a hydrogel bead capable of detecting hydrofluoric acid using an organometallic ligand compound that reversibly changes color depending on the concentration of hydrofluoric acid when coming into contact with hydrofluoric acid, and to a kit for detecting hydrofluoric acid comprising the same. In an embodiment, a method for preparing a hydrogel bead for detecting hydrofluoric acid comprises the steps of: mixing an organic compound, which contains an aromatic functional group having at least one hydroxyl group bonded thereto, with a solution of a metal-ligand compound that bonds with the organic compound, thereby preparing a mixed solution; dropping the mixed solution onto a gelling agent; and adding coagulating agent to the mixture resulting from the dropping step to form a porous bead.

Abstract: The present invention relates to a hydrogel, a preparation method thereof, and a pH sensor comprising the same, and more particularly, to a hydrogel, which can substitute for conventional pH paper, is continuously usable, can be used in various applications, and reversibly changes color depending on the pH of a sample, and to a pH sensor comprising the same. The hydrogel comprises: a polymer complex wherein a first organic compound containing an aromatic functional group having at least one hydroxyl group bonded thereto is joined to a carboxyl group-containing polysaccharide by a peptide bond; and an organic dye comprising a second organic compound containing an aromatic functional group having at least one hydroxyl group bonded thereto.