Nile red (also known as Nile blue oxazone) is a lipophilic stain. It is produced by boiling a solution of Nile blue with sulfuric acid. As can be seen from the structural formulae, this process replaces an iminium group with a carbonyl group. Nile red stains intracellular lipid droplets red. In most polar solvents Nile Red will not fluoresce, however when in a lipid-rich environment can be intensely fluorescent, with varying colours from deep red to strong yellow-gold emission. The dye is highly solvatochromic and its emission and excitation wavelength both shift depending on solvent polarity and in polar media will hardly fluoresce at all.

CAS：7385-67-3
中文别名：9-(二乙胺基)-5H-苯并[a]吩恶嗪-5-酮;尼罗丝;
英文别名：DCC impregnated tablets;Nile red;9-(diethylamino)benzo[a]phenoxazin-5-one;Nile Blue A Oxazone;
分子式：C20H18N2O2
分子量：318.369
精确质量：318.137
Psa：46.34
Logp：4.2922

UNII：P476F1L81G

外观与性状：固体
密度：1.23g/cm3
沸点：484.7ºC at 760 mmHg
熔点：203-205°C(lit.)
闪点：246.9ºC
折射率：1.643
稳定性：Stable. Incompatible with strong oxidizing agents.

安全说明：S24/25
WGK Germany：3
海关编码：2933990090