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Alexa Fluor™ 647 NHS Ester (Succinimidyl Ester), 1 mg - FAQs

Alexa Fluor™ 647 NHS Ester (Succinimidyl Ester), 1 mg - FAQs

View additional product information for Alexa Fluor™ 647 NHS Ester (Succinimidyl Ester) - FAQs (A37566, A20006, A20106, A37573)

2 product FAQs found

I am labeling a protein with Alexa Fluor 488 SDP ester. The manual recommends using a sodium bicarbonate buffer at pH 8.3. Can I use a different buffer instead?

Yes. The important thing is to use a buffered solution with a pH between 8.0 and 8.5. Do not use Tris buffer, which has amine groups. Most other buffers will work fine in that pH range. This is also true for other amine-reactive dyes, such as succinimidyl (NHS) esters or TFP esters.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

I am not going to use all of my Alexa Fluor succinimidyl ester reactive dye. Can I just make it up in DMSO and store aliquots at -20 degrees C?

This is not recommended. Any trace amounts of water in the DMSO can promote spontaneous hydrolysis over time. Even if using anhydrous DMSO, DMSO is hygroscopic; it readily absorbs moisture from the atmosphere over time. A better alternative is to dissolve the reactive dye in a volatile solvent, make smaller aliquots and then evaporate off the solvent using a vacuum pump. The smaller aliquots of solid reactive dye should then be stored frozen, desiccated and protected from light. Contact Technical Support by sending an email to techsupport@thermofisher.com for the recommended volatile solvent.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.