IV is different from IM in that the blood circulates and allows access to biochemicals breaking down foreign material. In the muscle it seems easier for something, especially insolubles, to get stuck for a while and turn to crap probably worst of all bacteria or fungi. That will give you an abscess. On the other hand, when shit does hit the fan with IV'ing you got sepsis on your hands which is obviously less contained than an abscess. All in all extremely nasty stuff you will want to avoid entirely.
Don't skimp out on the extraction, separation and filtering steps and the materials required. Yes wheel filters are not cheap and really cleaning your product up will take a bit of work, but I'd say it is a must if you are stubborn enough to inject extract to begin with.
Carbonate, bicarbonate, CO2 blood gas, sodium yeah all of those are endogenous to the human body - the carbonate is part of the pH buffering system actually. This helps stabilizing the pH.
{ I had a panic attack once from a drug cocktail, so bad that the hyperventilation caused metabolic acidosis: too much air means too much CO2 which makes the blood acidic. }
I used citric acid to dissolve my 5-MeO-DMT and DMT freebases. Just calculated stoichiometrically how much too add, only a very slight excess of acid was needed or none at all I am not sure IIRC.
Pure citric acid of course, no lemons. And the tryptamines are both synthetic, big difference. The last time I injected 5-MeO-DMT there was no burn or sensation at all but the first time maybe there might have been. Reasonable deviation from neutral pH shouldn't be a problem for the body, especially because of the pH buffer and because it is absorbed from the muscle over the course of a couple of minutes. By this I mean that I don't think it is necessary for me to use a digital pH meter to check for safety.
{ I don't think blood has pH 7.0 - oh apparently it is pH 7.35-7.45 ... }
By the way I did use a wheel filter, not for particulate matter but to maintain sterility.
Sorry for tangent reveries.