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Police tests for Ecstasy can produce false positives

Sir, for reasons I am unable to disclose I wounder if you could help me with a conundrum I have been saddled with.
Recently a colleague of mine was raided by the british drug squad due to a tip off that Ectasy was present in the house. However in the course of the raid they took samples from the waste disposal unit and found a trace of MDEA. Knowing this man and his life style it seems very odd that such a positive result has been found.

He has approached me as he is aware of my chemical background to see if I can come up with a reason for this positive test. Thus far in my enquiries I can only suggest that a chemical reaction of some kind has taken place to produce MDEA. They do use nutmeg to cook with on occasions. I believe that if this substance is mixed with orange juice the myristicin present in the nutmeg can cause a similar effect to drugs such as ecstacy. I wonder if chemical tests would reveal a positive test?

Reply from Alexander Shulgin:

You mentioned an instance where there had been the detection of a trace of MDEA in a waste-disposal unit. The evaluation of such a finding depends on the means of analysis that had been employed. The many types of analyses range from the presumptive tests (such as a color test) through immunological systems up to the state of the art spectrometers. All are subject to false positives, but they are increasingly rare as you go towards machines such as gas chromatography mass spectroscopy (GC-MS).

The color tests and related spot tests (usually field kits) are of value only for excluding possibilities -- they have no identification value of any kind. "We were wondering if this sludge contained LSD. LSD gives a purple color with reagent 'A'. The sludge gave a yellow color test with reagent 'A'. There is no reason to suspect LSD is present." If the sludge did indeed give a purple color, then you could justify taking a sample down to a forensic laboratory for further testing. One must always bear in mind that there are thousands of things that can give a purple color, besides LSD. That is the meaning of a presumptive test. If the color-generating part of the molecule being sought in your case is the methylenedioxy ring, then MDEA, or MDA, or nutmeg, or root-beer, or many other things could be positive. Quite possibly, any unexpected source of formaldehyde.

The in-between quality of analysis stage is usually some immunological assay such as EMIT. More selective, but within a family of chemicals, usually very cross-reactive. Evidence from such an analysis still requires further and more sophisticated confirmation. The same is true with TLC (Thin Layer Chromatography).

In any court presentation, GC-MS is absolutely required, and even then, it can be (and has been) successfully challenged.

Sorry not to be of more help, but I do not have the information needed to evaluate the findings fairly. The phrase, finding a trace of MDEA, has a sloppy ring to it.