I have always used 100mg/ml Nic for my mixing. With my final mix being 3mg.
Out of curiosity. Would there be any reason/benefit for me to switch to using dilutions of Nic like 48mg/ml or 250mg/ml?
Higher concentrations take up less space in your freezer, lower concentrations oxidize slower.
Thank you, I had a feeling space would be a possible reason. So if I were storing Nic for an extended period of time the lower the concentration the better?
100mg is the DIY standard in part because it is relatively safe for hobbyists to handle, whereas higher concentrations require professional level safety precautions. Pure nicotine is not something you want to risk splashing on your skin or in your eye.
48mg nic can be shipped by air, so that would be your choice if you live on an island or need nic in a hurry.
For DIY purposes, there's no real advantage to higher concentrations than 100mg. 250mg and above is USDOT HazMat. FedEx and UPS ground do accept HazMats, but charge an extra fee.
250mg/ml is overkill when not mixing for high concentration pod system juices. When the difference is using 3% of your volume for nic vs 1.2%, you won't gain much. When your juice is either 50% nic base or 20% nic base? Well, assume you use nic in a 50:50 base - just your nic will be getting into throat-rape territory for PG (25% before flavor, almost certainly over 30% after) while with the 250mg/ml you've only put 10% PG in your mix, so you can easily keep the PG down in the comfortable range.
48mg/ml? Well, if you want to mix with VG base nic, l would not want any higher concentration than that. And since it would be 6.25% of your mix, I rould avoid using 48mg/ml PG base nic.
Some Nic suppliers sell pure nic. Is that something to consider? If so, for long term storage?
PurNic is a brand of nicotine. "Pure nic" (pure nicotine) is 1000 mg/ml and only available to registered companies (i.e. not available to the DIY mixer).
EDIT: the highest concentration I have found, available to us, is 250 mg/ml (either freebase or nicotine salt).