Now I'd be the last one to say that this paper is representative of all the work done in the area of identifying "signature" chemicals for canine odour detection of MDMA, but a couple of points are worth noting.
Firstly the paper says nothing much of MDMA produced from safrole, as the benzaldehyde piperonal is the only marker found with a detection level in the mgs. But without a doubt some if not a considerable amount of MDMA is made from safrole. I could argue as to why I think this is true, but it's not really the place. However, if we are to assume at least some "smelly" pills we see in Australia
are made from safrole as the starting material, then it could be that dogs here are trained to detect this rather than other markers (incl MDMA itself) which are effectively odorless to dogs.
BUT, if you look at the tables and graphs of the above linked paper, it can be seen that minimum canine detectable levels are as as high as 10mg for piperonal, which was concluded to be the
most detectable substance. Safrole and Isosafrole at 10ug weren't detectable at all, i.e. 100% failure (Table 2) Interesting to compare to the 50% detection level at only 1ug - canine + human - of cocaines methyl-butyl ester impurity !
In fact, the threshold detection levels for law enforcement trained detector dogs and humans are similar as seen in Fig. 1.
Now I know humans and dogs have different degrees of sensitivity for various things and that a dog's sense of smell is generally greater for most things. But it is interesting that for many markers and those examined in this article, dogs performed rather poorly, especially with something like safrole, which I would have thought would be detectable at very low levels. Even piperonal did rather poorly compared to similar compounds; benzaldehyde was detectable at the 10ug level. They are both aldehydes, structurally similar and both with quite a smell, so I'm quite surprised at this variation. Piperonal smells like a cross between vanilla and marzipan; distingtively different to safrole- more sickly sweet. One difference which in part accounts for this is that piperonal is a solid and benzaldehyde a liquid at room temperature & pressure (.`. benzaldehyde vaporises easier).
In reading the conclusion -
"In studies where different over the counter tablets were analyzed, it was concluded that none of the headspace compounds in the original trials were present these tablets " -it appears this article achieved little in identifying suitable candidate molecules for training detection dogs to uncover MDMA made from different sources via different routes. Does this then mean that a "zip bag with 10 pills down the daks" could be safe?
I wouldn't put my faith in it but it does raise a few questions. I can think of a couple of ways of putting it to the test....
Conclusions
Overall, these results demonstrate that SPME/GC/MS combined with field tests using certified detector dogs is an effective method for identifying active odor signature chemicals in forensic specimens. For the drug studies it was found that passive adsorption using DFLEX devices containing activated charcoal was not sensitive enough to recover signature odors from the headspace of MDMA tablets. Only when very large samples (i.e. greater than 250 g) were extracted for extended periods of time (i.e. 1 week) were odors reliably detected. However, with headspace SPME it was found that with the implemented use of the CW/DVB and PDMS fibers with 3 h extraction times it was possible to obtain consistent signature odors from the headspace of a single MDMA tablet. Many compounds of interest were found to be present in the headspace composition of these tablets, including piperonal, MD-P2P and methamphetamine.
Through examinations of different tablets, however, it was concluded that the metamphetamine found within certain tablets were present due to its addition as an adulterant or contaminant and not the direct result of synthetic manufacturing and that piperonal and MD-P2P were the common chemicals seen in all samples tested. In studies where different over the counter tablets were analyzed, it was concluded that none of the headspace compounds found within these tablets were present in the headspace of MDMA tablets, therefore negating the possibility of false positive alerts from the canines in association with these commonly encountered tablets. Field studies directly focusing on the signature odor of MDMA have shown that canines are alerting to approximately 10–100 mg of the piperonal compound that is found exclusively in MDMA tablets.
These results need further verification through repetitive field studies, but the results to date indicate that piperonal is the dominant odor used by the canines tested when alerting to MDMA samples. Since MDMA manufactured through different synthetic routes can yield different signature chemicals, it is important to perform ongoing studies of headspace odors from current street samples and more than one MDMA training aid may be required for optimal performance in the future....
