CAS NO 494-38-2 Acridine Orange Base powder

General description

Acridine Orange base (3,6-Bis(dimethylamino)acridine) is a cell-permeable fluorescent dye that binds to nucleic acids. It emits green fluorescence when bound to dsDNA and red fluorescence when bound to ssDNA or RNA. It is also known to be a positive solvatochromic dye.

Application

Acridine orange has also been used as a lysosomal dye. It is widely used to detect the presence of homeopathic potencies.

Purification Methods

The double salt with ZnCl2 (6g) is dissolved in water (200mL) and stirred with four successive portions (12g each) of Dowex-50 ion-exchange resin (K+ form) to remove the zinc. The solution is then concentrated in vacuum to 20mL, and 100mL of ethanol is added to precipitate KCl which is removed. Ether (160mL) is added to the solution from which, on chilling, the dye crystallises as its chloride. It is separated by centrifugation, washed with chilled ethanol and ether, and dried under vacuum, before being recrystallised from ethanol (100mL) by adding ether (50mL), and chilling. Yield 1g. [Pal & Schubert J Am Chem Soc 84 4384 1962]. It was recrystallised twice as the free base from ethanol or methanol/water by dropwise addition of NaOH (less than 0.1M). The precipitate was washed with water and dried under vacuum. It was dissolved in CHCl3 and chromatographed on alumina: the main sharp band was collected, concentrated and cooled to -20o. The precipitate was filtered off, dried in air, then dried for 2hours under vacuum at 70o. [Stone & Bradley J Am Chem Soc 83 3627 1961, Blauer & Linschitz J Phys Chem 66 453 1962, Albert J Chem Soc 244 1947, Beilstein 22 III/IV 5490, 22/11 V 326.]