SAINMHÍNIÚ organic compound that has wide use as a synthetic colouring agent TAGAIRT 'fluorescein'. Encyclopædia Britannica, http://www.britannica.com/EBchecked/topic/211332/fluorescein [5.3.2010]
NÓTA It is prepared by heating phthalic anhydride and resorcinol over a zinc catalyst, and it crystallises as a deep red powder with a melting point in the range of 314° to 316° C (597° to 601° F). Fluorescein is used as a dye to colour liquids in analytic instruments, in cosmetics, and as a water tracer or marker. <p>It is also used in conjunction with a blue light to detect foreign bodies in the eye and detect damage to the cornea, and in angiography since it allows the blood vessels at the back of the eye to be photographed.