Patent ID: 7862779

Claim:
A composition of matter comprising an indicating dye encapsulated by an encapsulating material so as to provide an encapsulated dye composition, wherein: the indicating dye is hydrophobic and organo- or oleophilic and is selected from the class of anthracene, azo, anthraquinone, pyrazoline and quinone dyes and a combination whereof; the encapsulating material includes an acrylate polymer or copolymer, and is soluble in at least one liquid selected from the group consisting of acetone, gasoline, benzene, toluene, octane, heptane, hexane, pentane, kerosene, diesel fuel, a jet fuel, mineral of heating oil, light machine oil, motor oil, transformer oil, crude oil, distillation bottoms and reactor bottoms; and the encapsulated dye composition is in a form of a particle about from fifty to two thousand microns in diameter.