荧光素 MSDS2-(6-Hydroxy-3-oxo-(3H)-xanthen-9-yl)benzoic acid
Fluorescein is nearly inactive as a photodynamic sensitizer. Fluorescein consequently is almost useless as a photodynamic sensitizer, but it is of great value in fluorescence immunoassays. The fluorescein dye is a common fluorescent probe. Its very high molar absorptivity at the wavelength of the argon laser (488 nm), large fluorescence quantum yield and high photostability makes it a very useful and sensitive fluorescent label. Fluorescein is commercially available in many derivatives, such as fluorescein isothiocyanate and fluorescein succinimidyl ester, that can be covalently attached to macromolecules and to amino acids. The labeled molecules can be detected with very high sensitivity which is utilized in, for example, capillary electrophoresis. The emission spectrum of fluorescein overlaps extensively the absorption spectrum of tetramethyl rhodamine, which is a related strongly fluorescent dye, making this pair very suitable for energy transfer experiments to determine distances within and between labeled macromolecules. Fluorescein in aqueous solution occurs in cationic, neutral, anionic and dianionic forms making its absorption and fluoresence properties strongly pH dependent.
荧光素外观呈橙黄或浅橙红色结晶粉末。熔点314-316℃（分解）。溶于热乙醇、冰醋酸、碱溶液，呈绿色萤光，不溶于水、苯、氯仿和乙醚。
荧光素是汞溴红的中间体，可用作萤光光度分析试剂，测定氯、溴、碘、硫离子；氧化-还原指示试剂；生物染色剂。
荧光素可用邻苯二甲酸酐与间苯二酚在硫酸参与下反应制得。