There's this compound 9-Aminoacridine, that I need removed from the tissue slides it was applied to. Thing is everytime I use ethanol, Acetone, water, methanol, all the usual solvents; our pathologist says there are still remnants of it in tissue. It's key that we can remove it but it remains there nonetheless. I'm not sure what other solvents exist that can be used, it does happen to have a 2 aromatic rings in the structure. Let me know if there are solvents or a way to find them. In the SDS it says ethanol but that is a lie for my case I guess. Here's the structure: enter image description here

  • $\begingroup$ Maybe add some acid? $\endgroup$
    – Mithoron
    Jun 16, 2023 at 16:07
  • 1
    $\begingroup$ If you use the acridine as a stain / as an indicator and it hampers subsequent analysis / work, is there an established protocol in your field (maybe histochemistry) which uses a different compound instead which does not adsorb or (chemically) bind this much? Perhaps indication of the tissue (dermis, epidermis, subcutis, etc), protocol applied, intended analysis after the rinse can provide a direction. E.g., what concentration of remaining acridine would be below the limit of detection of the next analysis, or (compared to your signal of interest) weak enough (with a signal/noise ratio of 3)? $\endgroup$
    – Buttonwood
    Jun 16, 2023 at 17:06

1 Answer 1


The issue with removing biological stains is that they interact with cellular components and adhere to them. 9-aminoacridine intercalates with DNA, so it would take a large amount of solvent to remove it, by the law of mass action.

Since it is freely soluble in ethanol, the best course might be many repeated washings in ethanol, perhaps with gentle agitation (e.g., magnetic stirrer) at elevated temperature. However, that treatment is also likely to destroy the structure of the specimen.

It might be best to measure the effectiveness and harm of washing on a few specimens.

  • Using a UV lamp and UV-blocking filter on a light meter or camera (by looking at exposure info), measure fluorescence of the 9-aminoacridine to establish a baseline on how much stain is present.
  • Wash a set number of times.
  • Measure the amount of dye left, as above.
  • Examine under a microscope for damage.

You'll likely see a logarithmic drop in fluorescence, and then have to decide at what point the game is worth the candle, i.e., if dye removal is worth the damage to the slide, the time and the effort.

  • $\begingroup$ Thank you so much this is monuemntal help! 9-aminoacridine has a natrual fluoresence correct? $\endgroup$
    – Sciguyyy
    Jun 16, 2023 at 21:22
  • $\begingroup$ @Sciguyyy, "9-Aminoacridine is a fluorescent weak base which distributes across the plasma membrane according to the pH gradient, and can be used to monitor changes in intracellular pH in eukaryotic cells." sciencedirect.com/science/article/pii/0014579384811400 $\endgroup$ Jun 16, 2023 at 21:50
  • $\begingroup$ So do you think under a hood UV light, I should see some fluoresence? And your comments are super appreciated, this could beyond help my work, thank you! $\endgroup$
    – Sciguyyy
    Jun 17, 2023 at 16:15
  • $\begingroup$ @Sciguyyy, sorry, but it's doubtful I can be of much practical help beyond the above suggestion. Try it and see. $\endgroup$ Jun 18, 2023 at 1:42
  • $\begingroup$ Thanks!!! I'll play around with some tools. $\endgroup$
    – Sciguyyy
    Jun 18, 2023 at 23:35

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