structure and normalization help

[Robert Jackson]

I'm not a newbie at using mysql, but I am an uncarved block (bloke?) in the ways of database normalization. I've read probably 30 articles dealing with the subject but nothing satisfies. I can do it to an extent but one thing has been plaguing me for a long time. It’s a product catalog that has the following characteristics:

Any given product of ours could be categorized as follows, Antigens, Immunoassays, Polymerases. An Immunoassay can have 4 possible types RIA, ELISA, IRMA, or LIA. But more importantly it (a RIA ELISA IRMA or LIA) can also test for one or all of the following parameters, like adrenaline, noradrenaline, dopamine. i.e. (an RIA called BA-0200 can test only for noradrenaline, but a RIA called BA 1600 can test for all of the aforementioned.) My question is how to break these down. I get lost in the many to many relationships that occur as you move down the tree. I 've done it multiple ways using parent ids or entirely separate tables and nothing I do seems to complement the system to get maximal functionality in pulling the information back out, without sometimes writing ridiculous queries. I want to make this as manageable and scaleable as possible for a web page. Can anyone help me? I'll send you a set of data if you need to play with it.