Froehde reagent

The Froehde reagent is used as a simple spot-test to presumptively identify alkaloids, especially opioids, as well as other compounds. It is composed of a mixture of molybdic acid or a molybdate salt dissolved in hot, concentrated sulfuric acid, which is then dripped onto the substance being tested.

The United States Department of Justice method for producing the reagent is the addition of 100 mL of hot, concentrated (95–98%) sulfuric acid to 0.5 g of sodium molybdate or molybdic acid.^[1]

The Virginia Department of Forensic Science method uses 0.5 g ammonium molybdate per 100 mL H₂SO₄ (conc.)^[2]

Unheated sulfuric acid can be used to prepare the reagent in a less dangerous manner, but 2-4 hours must be allowed for the molybdate to dissolve.

Final colors produced by Froehde Reagent with various substances

Substance	Color
Amphetamine	No reaction[3] or Red[4]
Cathinone	No Reaction[5]
Methcathinone	No Reaction[5]
4-MMC	No Reaction [5]
3-FMC	No Reaction[5]
MDMA	Black[3]
Methylone	Bright Yellow[5]
MDPV	Bright Yellow[5]
Butylone	Yellow > Green[6]
3,4-DMMC	Light Brown[6]
Naphyrone	Orange[6]
PMA	Pale Green[3]
PMMA	Pale Green[3]
4-MeO-PCP	Light Yellow[6]
Methoxetamine	Yellow - Green[6]
3-HO-PCE	Black[6]
5-MeO-DALT	Yellow[6]
4-AcO-DALT	Yellow > Green[6]
4-HO-MET	Yellow > Green[6]
4-HO-MIPT	Yellow > Green[6]
4-AcO-DET	Yellow > Green[6]
aMT	Yellow[6]
5-IT	Red Brown[6]
5-APB	Dark Purple[6]
6-APB	Purple[6]
Camfetamine	Tan > Dark Yellow[6]
Methiopropamine	Light Brown[6]
MDAI	Green > Black[6]
5-IAI	Orange[6]
Allylescaline	Green > Black (fast)[6]
2C-T-2	Orange > Purple[6]
2C-B	Yellow[2]
2C-P	Green[6]
b-methoxy-2C-D	Red[6]
Acetaminophen	Pale Blue[2]
Aspirin	Grayish Purple[1] or Blue > Purple[2]
Alimemazine	Purple Red[4]
Chlorphentermine	Green[4]
Chlorpromazine HCl	Very Deep Red[1][4]
Contac HCl	Moderate Olive Brown[1]
Dimethoxy-meth HCl	Very Yellow Green[1]
Diphenhydramine	Orange[4]
Doxepin HCl	Deep Reddish Brown[1][4]
Dristan	Light Bluish Green[1]
Ephedrine	Brown[4]
Exedrine	Brilliant Blue[1]
Flurazepam	Orange[4]
LSD	Moderate Yellow Green,[1] Yellow Green[4]
Mace	Light Olive Yellow[1]
MDA HCl	Greenish Black[1][4]
Mescaline	Green or Brown or Light Yellow[4]
Meperidine	Grey[2]
Modafinil	Deep orange/red[7]
Morphine monohydrate	Deep Purplish[2] Red[1] > Slate[2]
Heroin HCl	Deep Purplish Red[1][4] > Green[2]
Opium	Brownish Black[1][4]
Oxycodone HCl	Strong Yellow[1][2] - Blue[4] or Green[4]
Codeine HCl	Very Dark[1] Green[4] > Red - Brown[2]
Hydromorphone	Blue > Purple[2]
Hydrocodone	Light[2] Yellow[4]
Pentazocine	Blue[2][4]
Pethidine	Yellow[4]
Phenoxymethylpenicillin	Blue[2]
Phenyltoloxamine	Green[4]
Promazine	Orange[4]
Promethazine	Purple Red[4]
Propoxyphene HCl	Dark Grayish Red[1][4] or Brown[2]
Propylhexadrine	Purple Red[4]
Sugar	Brilliant Yellow[1]
Salicylic acid	Purple Red[4]
Tetracycline	Purple Red[4]
Thioridazine	Purple Red[4]
Guaifenesin	Green with Purple streaks[2]
Methapyrilene	Purple[2]
Pyrilamine	Purple[2]
Trifluoperazine	Orange[4]
Triflupromazine	Orange[4]

See also

• Pill testing
• Dille–Koppanyi reagent
• Folin's reagent
• Liebermann reagent
• Mandelin reagent
• Marquis reagent
• Mecke reagent
• Simon's reagent
• Zwikker reagent

References

1. "Color Test Reagents/Kits for Preliminary Identification of Drugs of Abuse" (PDF). Law Enforcement and Corrections Standards and Testing Program. July 2000. Retrieved 2011-07-24.
2. "Controlled Substances Procedures Manual" (PDF). Virginia Department of Forensic Science. 2013. Retrieved 2013-08-06.
3. EMCDDA (30 Mar 2011). EMCDDA Risk Assessment: Report on the Risk Assessment of PMMA in the Framework of the Joint Action on New Synthetic Drugs. Dictus Publishing. p. 54. ISBN 978-3-8433-2695-7. Retrieved 2012-01-25.
4. "Clarke's Analysis of Drugs and Poisons". Pharmaceutical Press. 2011. doi:10.1080/00450618.2011.620006. ISBN 978-0-85369-711-4.
5. Toole KE, Fu S, Shimmon RG, Kraymen N (2012). "Color Tests for the Preliminary Identification of Methcathinone and Analogues of Methcathinone" (PDF). Microgram Journal 9 (1): 27–32.
6. "Color Tests and Analytical Difficulties With Emerging Drugs of Abuse" (PDF). Johnson County Sheriff’s Office Criminalistics Laboratory. 2012. Retrieved 2013-07-16.
7. "Modafinil reaction with the Froehde reagent and others". Reagent Tests UK. 13 December 2015. Retrieved 18 December 2015.

External links