hiya! im here to help you out.
there are 58 tonics in total. so that trophy is really saying “collect, invent and find ALL tonics!”. Plasmids, though, are not tonics, so they do not count.
Now im a bit of a freak and often like to check every room and every crack of that rooms until im sure i had found everything. and that's why i got the 58 tonics on my first run… but I can understand that it's very easy to miss at least one! so all I can say is count all the tonics you have (exclusind plasmis of course) and once you know how many you have, you then now what you're missing! If you really can't find them, then write down the names of the tonics you have and check an online guide. since it was previously a 360 game, im positive there will be one already up.
also, make sure you have invented the three tonics from the u-invent range. and also bought all the tonics (not the plasmids) from the galthiers garden using your ADAM. if you've rescued them all and have been smart on what you were buying, you should have at least 80 ADAM left over even after buying all tonics. But only if you DIDN'T get all of the plasmids. I didn't bother getting the cyclone trap, bee swarm or Winter blast because they are not needed!
Another thing is to make sure you have researched EVERYTHING! researching gives you a couple tonics here and there (the best one is natural camoflauge). And finally, you need to save ALL of the little sisters to get ALL of the tonics.
if you still don't have them all after that, then you need to go back to each level, check the maps and make sure you haven't missed out any rooms such as the ones that need to have something lit on fire, or struck with lightning.