Manipulating hydrophilicity of conventional dye molecules for water tracer applications

A composition comprising:

• a functionalized fluorescent dye, wherein the functionalized fluorescent dye comprises an isothiocyanate-containing dye functionalized with a functional group comprising a primary amine, wherein:
• the isothiocyanate-containing dye is selected from the group consisting of Rhodamine B isothiocyanate, or tetramethylrhodamine isothiocyanate;
• and
• the functional group is selected from Group I or Group II, wherein:
• Group I consists of aminomethanesulfonic acid, 2-aminoethanesulfonic acid, 3-amino-1-propanesulfonic acid, 2-aminoethyl(trimethyl)azanium, and 3-aminopropyl(trimethyl)azanium;
• and
• Group II consists of 4-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, 3-amino-4-hydroxybenzenesulfonic acid, 4-amino-3-hydroxybenzenesulfonic acid, (4-aminophenyl)-trimethylazanium, 6-amino-4-hydroxy-2-naphthalenesulfonic acid, 1-amino-2-naphthol-4-sulfonic acid, 7-aminonaphthalene-1,3-disulfonic acid, 4-aminonaphthalene-1,7-di sulfonic acid, 8-amino-1,3,6-naphthalenetrisulfonic acid, and 8-aminopyrene-1,3,6-trisulfonic acid.