Bio-Synthesis offers Alexa 633 fluorescent dye oligonucleotide labeling services. Alexa 633 is near infrad red,  far red fluorescent dye with an excitation maximum of 633 nm and 635 nm. Alexa Fluor® 633 and Alexa Fluor® 635 dyes are a perfect match to the 633 nm spectral line of the He-Ne laser and the 635 nm spectral line of red diode lasers. The Isomeric mixture of oligo conjugates are bright and photostable, with excitation/emission maxima of ~632/647 nm. The fluorescence of this long-wavelength dye is not visible to human eye but it can be deteced by most imaging system.

  • Far-red fluorescence
  • Good spectral separation from green fluorophores
  • pH-insensitive fluorescence between pH 4 and 10

Alexa 633 dye can be incorporated at any position within an Oligonucleotide. A primary amine modified oligonucleotide is used to covalently attach with dye via NHS conjugation chemistry; other cross-linking chemistries are also available depending on particular project specifications. Dual HPLC purification is used to remove failure sequences during first HPLC purification,  after labeling, the second HPLC is performed to remove unlabeled oligonucleotides and excessive dye in order to obtain a full length labeled oligonucleotide.

Contact us for Alexa 633 fluorescent dye oligonucleotide labeling services.


Product Information


Product Name:

Alexa 633 Oligo Labeling


Fluorescent dye Label, far-red dye

Modification Code:


Excitation (nm):


Emission (nm):


Extinction Coefficient, ε(λ):



Dual HPLC required

Delivery Format:


Shipping Conditions:

Room Temperature

Storage Conditions:

-20°C To -70°C
Oligonucleotides are stable in solution at 4°C for up to 2 weeks. Properly reconstituted material stored at -20°C should be stable for at least 6 months. Dried DNA (when kept at -20°C) in a nuclease-free environment should be stable for years.