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.
| 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 | Greyish 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 greyish 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
editReferences
edit- ^ a b c d e f g h i j k l m n o p q r "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.
- ^ a b c d e f g h i j k l m n o p q r "Controlled Substances Procedures Manual" (PDF). Virginia Department of Forensic Science. 2013. Archived from the original (PDF) on 2013-08-13. Retrieved 2013-08-06.
- ^ a b c d 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.
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac "Clarke's Analysis of Drugs and Poisons". Pharmaceutical Press. 2011. doi:10.1080/00450618.2011.620006. ISBN 978-0-85369-711-4. S2CID 71790993.
- ^ a b c d e f 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. Archived from the original (PDF) on 2013-11-26. Retrieved 2013-10-28.
- ^ a b c d e f g h i j k l m n o p q r s t u v w "Color Tests and Analytical Difficulties With Emerging Drugs of Abuse" (PDF). Johnson County Sheriff’s Office Criminalistics Laboratory. 2012. Retrieved 2013-07-16.
- ^ "Modafinil reaction with the Froehde reagent and others". Reagent Tests UK. 13 December 2015. Retrieved 18 December 2015.