Chemistry behind testing kits - ups and downs?

[Chameleon]

Out of interest, what is the chemistry behind testing kits?
Things to think about as an organic chemist:
i) What if there is a mixture of MDMA/speed/crap? What proportions of these give test results that are misleading (e.g. is the signal/reaction for MDMA 10x as strong as for speed or caffeine vice versa?)
ii) One should be careful if people know how to fool test kits with cheaper/legitimate chemicals? Other legal amines?
iii) If you wanted to be really paranoid, to fool the taste/scraping test you could coat the pill with good stuff and put crap/placebo in the middle.
I realise these things aren't nice (and don't want to give any shady dealers ideas), and as a consumer of untested pills, some of which have been duds (I'd say 1 in 8 have been crap) I'm all for testing.
All, I'm saying is that we should realise that simple colorimetric chemical-reaction based testing is _not_ a cure all. That being said, its better than nothing!
Chameleon.

 

[aj]

i) What if there is a mixture of MDMA/speed/crap? What proportions of these give test results that are misleading
++ If there is a mix, the reaction will be accordingly. Not to darkpurple, it is not an xtc like substance.
ii) One should be careful if people know how to fool test kits with cheaper/legitimate chemicals? Other legal amines?
++ There are no reports like that yet. However, DXM could fool inexperienced users but once you've seen a mdma reaction, you know the difference.
All, I'm saying is that we should realise that simple colorimetric chemical-reaction based testing is _not_ a cure all. That being said, its better than nothing!
++ Exactly, it is better than nothing. Definitely not a solution to this testing problem. It is a first step. We are trying to improve and make better testers ;-)
This whole testing thing also aims to raise awareness among xtc users and start a discussion.
aj

 

[PhreeX]

I don't think any of these fears would ever become a real problem ..
Few people even know what a testing kit is, fewer use them ..
Do you know how hard it would be to 'coat' a pill with something that taste like MDMA?
I don't think there is any risk of pill pressers trying to evade pill testers ..