What's this white powder?

September 24, 2012 8:58 PM

What (if any) powdered drugs, illegal or pharmaceutical, can be identified by taste or smell - you know, like how the cops do on TV?

[Bonus question: what about trained police dogs - could they identify powdered drugs?]

My guess here is that some illegal substances could be identified, not from a primary taste or smell, but perhaps from the residue of chemicals used in the production process (assuming said process is a little less "refined" than that of a pharmaceutical multi-national)?

posted by forallmankind to Science & Nature (15 answers total)

Not so much taste, but cocaine should work as a topical anaesthetic, and thus numb the tongue. Dentists use(d) it, IIRC.
posted by pompomtom at 9:07 PM on September 24, 2012

Not so much taste, but cocaine should work as a topical anaesthetic, and thus numb the tongue. Dentists use(d) it, IIRC.

Disgusting historical note: cocaine was (and still is, to an extent I think) used as a local anesthetic for nose and eye surgery, because it has the additional effects of reducing the blink reflex and acting as a vasoconstrictor.
posted by pullayup at 9:15 PM on September 24, 2012

Police dogs can definitely identify certain drugs by smell. A scent-hound's sense of smell is incomparably more sensitive than a human's for both distance and minuteness. Powdered drugs are probably the easiest as they have the best aerosolizability.
posted by griphus at 9:29 PM on September 24, 2012

Dogs can indeed be trained to detect a wide variety of things by smell, including illegal drugs. Keep in mind, however, that there's been some effort made recently to regulate this practice. The reason being that a dog may be trained, unintentionally or maliciously, to cue off its handler rather than an actual smell, giving police probable cause for what would be an otherwise unjustifiable search.
posted by 2N2222 at 9:41 PM on September 24, 2012 [2 favorites]

How positively do you want to identify something? Taste is fine if you want to know if you're dealing with salt or sugar (or in the case of your TV cops, cocaine or powdered sugar or baking soda) but if you're just handed a chemical and it could be anything on Earth, it gets a lot harder. If someone handed me a chemical, and it could be anything on earth, there's no one indent-a-tron you could just inject the sample into and get back an ID. Typically you do orthogonal testing where it has to be like a in test A, b in test B and c in test C until you have little doubt what you're dealing with.
posted by Kid Charlemagne at 10:04 PM on September 24, 2012 [1 favorite]

the Tribune reported today (Jan. 6) that only 44 percent of sniffer dogs' positive signals led to the actual discovery of drugs or paraphernalia. The Tribune's analysis also shows that among drug alert roadside traffic stops of Hispanic drivers, the sniffer dogs' success rate was 27 percent.
posted by drjimmy11 at 10:35 PM on September 24, 2012 [11 favorites]

Cocaine and amphetamine sulphate can most assuredly be identified by smell.
posted by anagrama at 4:45 AM on September 25, 2012

cocaine and ketamine both have very distinct identifiable flavours, ones that you could never mistake for anything else if you've tasted them. Ditto for pcp, but that's not really a "powder" per se- it's cut with other substances, usually icing sugar, to make it snortable. (the bitter chemically taste of pcp offset by the incredibly powerful sweetness of icing sugar is one of the more revolting- and distinct- flavours and aromas in the whole entire world. However, it's a pretty generalised "chemical" aroma- I've smelled chemical cleaning agents and, for a moment, thought that I was getting a whiff of pcp).

The thing though is that many many drugs just taste bitter, so I think that you might be hard-pressed to find a lot of distinctivley flavoured drugs. Also, most pharmmeceutical drugs that are powders are sold in capsules, so a lot of people will have no idea how they smell or taste.
posted by windykites at 5:18 AM on September 25, 2012 [2 favorites]

MDMA also has a fairly identifiable taste. Ketamine is actually sometimes flavored-- at least it was 10 years ago when I was buying it. The drip is completely foul tasting otherwise. I don't know that I've ever noticed a smell for any of them. Cocaine is also easily identifiable because its a topical anesthetic.
posted by empath at 6:10 AM on September 25, 2012

Are you asking in your bonus question if a police dog could differentiate say, meth from cocaine? I have met the local PD's drug-sniffing dogs at the county fair and as I understand it they give the same signal no matter what kind of drug they find. I suppose they could be trained to give a different signal for each drug but I'm not sure PDs would find that valuable enough to train into them when they can just send the drugs to a lab.
posted by IndigoRain at 7:58 AM on September 25, 2012

I remember a professor of chemistry who worked in this area (applying forensic chemistry to illegal drugs) saying that many are identifiable by the smells of their contaminants. Specifically:
- Heroin typically smells of vinegar, because it is made from morphine by the addition of acetic anhydride, which also produces acetic acid as a byproduct.
- Cocaine hypochloride typically smells of hydrochloric acid.
- Amphetamines typically smell of mineral oil.
posted by James Scott-Brown at 8:47 AM on September 25, 2012

Cocaine is indeed still used as a topical anesthetic. It's Schedule II in the US, meaning it's legal to prescribe, though naturally its use is heavily restricted.

The drug itself technically has no smell, but it hydrolyzes in air to produce a chemical called methyl benzoate, which has a distinctive and pleasant smell. It smells a little bit like paper currency. I've heard that drug-sniffing dogs will occasionally find large bundles of cash by mistake. The similarity is probably a coincidence, but it might also be due to the fact that the average dollar bill has something like 10 nanograms of cocaine imbedded in it.
posted by dephlogisticated at 8:49 AM on September 25, 2012 [1 favorite]

the average dollar bill has something like 10 nanograms of cocaine imbedded in it.

seriously? Like, from people using bills to snort with? Or are you making some kind of drugs-and-money joke that I'm not picking up on?
posted by windykites at 11:31 AM on September 25, 2012

Of the 234 U.S. bills collected in 17 large and small cities, nearly 90 percent had traces of cocaine, especially in larger cities such as Baltimore, Boston, and Detroit. Ninety-five percent of the dollars found in Washington, D.C., had cocaine embedded in their fibers—among the highest in the study.
posted by griphus at 11:34 AM on September 25, 2012 [1 favorite]

From experience of illegal use: the nasal drip associated with snorting ecstasy tastes different than the nasal drip of cocaine, but that's not noticeable right away, and it's entirely possible this is due to fillers typically used for either drug in my part of the world.

Marijuana, of course, has a distinctive smell, but I've been accused of smoking it by a cop when all that I'd been smoking was too much tobacco.

From my experience administering drugs in a hospital: the only thing that I remember with a really distinct odor was phenergan (aka promethazine), an IV anti-emetic typically given alongside opiate analgesia. Phenergan is mildly sedating, so there's some potential for abuse, but the high's apparently not good enough to justify any kind of illegal market in the stuff. Interestingly, I, the heaviest smoker around, could easily tell when somebody was drawing up some phenergan, and many other nurses couldn't smell it.
posted by nathan v at 11:28 PM on November 16, 2012