Preservation of liquid MDMA

[primal440]

Hello, recently SWIM's mom acquired some grams of high-quality MDMA and given that she doesn't own a scale she decided to dilute the powder in 10 mls. of liquid and dose with a syringe. Apparently, because there were no other options available she was forced to use tap water and now she is afraid she might have fucked up. She put the syringe in the freezer around 6 hours after doing the preparation and now she is concerned about the drug's degradation, because she then tried it again and had minimal effects (although it might have been because of prior usage of a mild SSRI less than a week before).

Her question is has she really fucked it up so bad or is she just too alarmed? Is there any solution to stop the degradation of the solution besides taking it sooner than expected? And could she in some way carefully titrate, upping the dosage in case she needed more of the solution to get high? Thank you very much, I hope nobody gets as foolish as she; although SWIM can very confidently say that mixing it with vodka hasn't altered the potency of the solution for the 6 months it has spent in the fridge. Alcohol and apparently distilled water would do the same; and of course, storing it in powder form would do as well.