Talk:Marquis reagent

Vitamin-C tablet reaction vs amphetamine

The Marquis reagent is used by police all over the world to test pills for amphetamine and various drugs. What the police don't know, is that this test isn't fool-proof. The test reacts even to glucose in the same way it would with amphetamine, so basically even if they test a pill with vitamine-C (that has glucose in it), the test will show positive for amphetamine. —The preceding unsigned comment was added by Mr Soros (talk • contribs) 09:52, 4 July 2007 (UTC).

Please provide a source for that claim. Also keep in mind that the Marquis reagent test is generally only used as a preliminary test. Forensic tests such as GC/MS are much more reliable. Simishag 21:18, 4 July 2007 (UTC)

Yes, I know I don't have any sources, which is why I only added this to the talk page: I have not yet found any sources for this on the internet. But I still want people to be able to find this information, because it can be vital. For me for example, it is, because I have been found with 12 pills of vitamin-C by the police, who tested the pills with this test, and the test showed positive for amphetamine (brown). Mr soros 23:25, 4 July 2007 (UTC)

Couple of questions here: How do you know the field test being used was a marquis reagent? Did you ask him, also how do you know what color it turned? I just don't picture an officer allowing a person suspected of narcotics possession to stand there along side him and watch anxiously to see what colors develop. I'm being facetious of course, and I have no idea the circumstances, I'm just curious how you knew it to indeed be a marquis reagent. As you observed, your experience is anecdotal and that tends to become problematic. You did the right thing by throwing it up on here first so we can speculate about your finding at leisure. So lets speculate:

Firstly, it would help to clear up what you meant by glucose? Are you perhaps referring to the D-glucose units found in powdered cellulose, a common filler used in pressed tablets? Glucose, sucrose, cellulose, regardless, they are all likely to have the same color result in the presence of sulfuric acid; Black, as carbon is liberated after dehydration of the carbohydrate.

The bulk of any vitamin c tablet is going to (hopefully) be ascorbic acid, although a little bit of cellulose is going to going to taint the reaction greatly, obscuring the subtle colors evolved during the reaction with ascorbic acid with the highly pigmented carbon, and its broad-spectrum absorption bands, hence the brown, dull or lack of color.

Saying what the resulting mess is after the reaction has completed, isn't very helpful. You have to carefully watch what colors develop, and at what increment of time it happened, to be able to accurately predict which vitamin your trafficking accost state lines that particular night. Did it start out orange then turn to brown? If so, that might be interesting to note, but I'm confident It would still act notably different than amphetamines, where nitrogen would be present unlike any other compound we have been speculating at thus far.

In conclusion, the notion of a cop using a marquis reagent, roadside, under poor lighting conditions, without a stopwatch or failing to index changes over the development of time, then taking a brownish or or anything dark or void of color, that could have easily be the result of fillers in nearly every commercially produced tablet, or sugar or any other number of possible and deliberate adulterants, and be able to say conclusively and with confidence that there was amphetamine in those tablets, is laughable. My advice to you would be to take solstice in the fact that they are going to pay good money to elucidate the mass of ascorbic acid, which I could have looked up in any number of books or websites for half the cost. Okay, I'm going to stop now before I breach Wikipedia's rant policy...

Well some of your assumptions are incorrect. I was taken to the anti-drug headquarters for the testing of tablets. Also, since I was vehemently affirming I was just carrying vitamin C tablets, the cops did the test right in front of my eyes. I thought it was a marquis test because when I got home from the police headquarters, I searched all over the internet to find out what happened (amphetamines in vitamin C???), and finally someone answered on the #chemistry channel on freenode and this was his explanation. I put it on wikipedia so anyone in my situation would find this information more easily. Now, 10 years later, I know they figured out it was vitamin C since I never had any follow up about this case.Mr soros (talk) 15:14, 14 November 2017 (UTC)

DrBurningBunny (talk) 17:55, 22 April 2011 (UTC)

Opiates

In the second paragraph, methadone is listed as an opiate that can be tested with Marquis. Marquis can be used to test methadone, but methadone is not at all an opiate, and should not be listed as such. It has opiate-like effects on people, but it is not structurally related to any opiates and therefore would not react with Marquis in the same fashion as, say, heroin. 206.194.127.112 (talk) 22:43, 6 April 2009 (UTC)

Alloys

There are three significant Alloys in the List, which have almost no explanory power at all:

- Dristan is an Alloy of Acetaminophen, Phenylephrine and Chlorpheniramine.
- Excedrin enthält Paracetamol, ASA and caffeine
- Mace contains as a grinded pit of a fruit a lot of different Alkaloides

I would delete all of them because each of these "test scores" is a mixture of colors which leads to no concrete inference. --78.52.194.180 (talk) 15:16, 6 August 2010 (UTC)

Who were they?

Marquis, Mecke, Mandelin, Simon and even Robadope... Everyone knows these reagents, but who were they named after? 91.85.166.51 (talk) 18:00, 19 March 2012 (UTC)

• Eduard Marquis. No article, yet. All the best: Rich Farmbrough, 13:09, 11 March 2019 (UTC).