The Home Scientist 018 - Forensic Presumptive Drug Testing I

Forensic presumptive drug testing using Marquis Reagent and Mandelin Reagent to test various over-the-counter drugs.

For more details, see:

Color Test Reagents/Kits for Preliminary Identification of Drugs of Abuse
http://www.ncjrs.gov/pdffiles1/nij/183258.pdf

Viriginia Department of Forensic Science CONTROLLED SUBSTANCES PROCEDURES MANUAL
http://www.dfs.virginia.gov/manuals/controlledSubstances/procedures/221-D100%...

Mandelin Reagent
0.1 grams of ammonium metavanadate dissolved in 10 mL of concentrated sulfuric acid.

Marquis Reagent
10 mL of concentrated sulfuric acid added to 0.5 mL of 37% formalin (formadehyde) solution.

Substances tested:

1. Aspirin

2. Loperamide hydrochloride (Imodium antidiarrheal)

3. Chlorpheniramine maleate (allergy medication)

4. Loratidine (Claritin, allergy medication)

5. Diphenhydramine (Benedryl, allergy medication)

6. Meclizine (dramamine, antinausea medication)

Category:

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[CarnalDiafragma]

This is really good! I've made ammonium metavanadate yesterday and was looking for a good use. This is a great idea.

I am really wondering about the chemistry behind these tests. Why do you get those specific colours? What happens?

[TheHomeScientist]

@CarnalDiafragma

Good question, but I'm not sure anyone really knows the answer. The reactions that are occurring must be extremely complex, producing numerous chromophores that change as the reaction progresses. I'm not sure how even to begin investigating the actual mechanisms.

[slateflash]

Would caffeine or theobromine give a positive reaction?

[TheHomeScientist]

@slateflash

Why not try it and find out?

[Gmc42082]

would this work with a urine sample,or would it be too dilute for this type of test. i think those types of tests(homekits) use some type of an antibody reaction.

[TheHomeScientist]

In practical terms, no. Presumptive color spot tests are now used only on actual suspect material. Before instrumental analysis, CSTs were sometimes used to test body fluids. Depending on the compound, how much of it is metabolized versus excreted unchanged, and the sensitivity of the reagent, forensic toxicologists through the mid-20th century were sometimes able to detect and identify specific alkaloids from body fluid samples. However, they had to do a lot of separation/purification first.

[drfinkster]

Meclozine is sometimes sold as a "less-drowsy formula" of Dramamine, but plain old Dramamine is always the combo of diphenhydramine and 8-chlorotheophylline. Ironic that the "more drowsy" Dramamine actually has a CNS stimulant in it, huh?

[drfinkster]

I know this video's been posted for a while now, but I just wanted to correct a minor error you made towards the end. Your last test was with Meclozine, an OTC antihistamine and anti-nausea medicine. You said this is usually known as Dramamine. This is not the case. Dramamine is usually dimenhydrinate, which is actually a combo of 2 drugs - diphenhydramine (aka Benadryl) and 1,3-dimethyl-8-chl​oroxanthi​ne, a synthetic xanthine stimulant. Meclozine (Bonine) is an unrelated piperazine derivative.

[98JMA]

@bletnahuj

That would (a) produce hot sulfuric acid fumes, and (b) cold sufuric acid is scary, hot sulfuric acid is terrifying. It's easier just to buy drain unblocker conc. sulfuric acid.

[bletnahuj]

@breathfire2001

Boil down some battery acid you can find at your local automotive supply store

[CarnalDiafragma]

@TheHomeScientist

Well, after some research, I know the Chen-Kao Test forms coloured chelate complexes with copper sulphate and Simons tests form complexes with [ONFe(CN)5]2- (nitroprussid-acetaldehyde I believe, a prussian blue derivative), So my guess is that the Mandelin reagent forms coordination complexes with vanadium. But I can't even guess how the Marquis works, because there is no d-block metal for coordination complexes in the reagent.

[Breathfire2001]

I would like to make some marquis reagent but I'm not sure I can obtain such concentrated H2SO4. How concentrated must it be to work? And is there an OTC source for such concentrations?