I looked at the google results before posting this thread. All titration kits and methods i've seen deal with freebase nicotine, which gets converted to nic salt with acid, so titrations are basically strong acid reaction with freebase nic. In my case i am starting with nic salt.
Have you tried to estimate concentration of the nicotine and solvents, and compare it to the result obtained? You have 1.44 g of the solution and tens of mg of nicotine, does it add up?
The estimated concentration of nicotine in solvent is 24mg/ml (assuming nic salt manufacturer actually sold me 48mg/ml nic as advertised). The value i get from titration by NaOH is 26mg/ml from the first equivalence point... Don't know how to interpret or what to do with 2nd equivalence point.
I guess i'll try with H2SO4 and/or HCl tomorrow to see if i get similar results. Need to create standard solutions first though... I was worried about titrating with strong acid, just like a freebase nic, because of, to me unknown effect by acetic or benzoic acid. But since their pKa is around 4, i guess they'll pick up H+ from HCl nicely, in effect leaving ph unchanged until equivalence point.
All videos for nic titration kits i saw online stated that it is for freebase nic only, not for nic salts; and all these kits were HCl based... so i did not think far enough...