Seminaphtharhodafluor

Seminaphtharhodafluor or SNARF-1 is a fluorescent dye that changes colour with pH. It can be used to construct optical biosensors that use enzymes that change pH.

The absorption peak of carboxy SNARF at pH 6.0 is at wavelength (515 and) 550 nm, while that at pH 9.0 is at 575 nm.

The emission peak of carboxy SNARF at pH 6.0 is at wavelength 585 nm, while that at pH 9.0 is at 640 nm.