Barksdale, Larry; MA
Date of this Version
The Marquis reagent is a well-established and widely used chemical presumptive test for 3,4-Methylenedioxymethamphetamine (MDMA) and methamphetamine. It is composed of concentrated sulfuric acid and 40% formaldehyde, which act upon alkaloids causing them to complex into larger molecules. This complexation causes a color change that can be visually interpreted as a positive or negative result. Almost any sugar molecule can be complexed in this way as well, due to their many OH groups. Experimentally it was found that the sugar molecules did complex with one another when the Marquis test was administered. The color produced by this reaction was brownish-red. Meaning it tested positive for amphetamine, but not methamphetamine specifically. Methamphetamine is expected to turn a light blue color, while other amphetamines are expected to turn brownish-red. A principal molecular difference between methamphetamine and common sugars is the presence of carbon-carbon double bonds. All amphetamine molecules contain three of these pi bonds, while common sugars such as sucrose, glucose, and fructose do not contain any pi bonds. The Baeyer test is a well-established organic chemistry test that is not currently used in forensic field tests. The test uses a 1% potassium permanganate solution and acetone to react with pi bonds. If pi bonds are present in the sample, an aqueous layer will appear in the violet solution. If not, the solution will be uniformly violet. This was supported as an effective method of differentiation as in our experimental tests the control samples of pseudoephedrine were consistently positive for the test. While the samples of common sugar consistently did not test positive. This implies that there is a consistent issue of sugar samples testing positive for amphetamines, and the Baeyer test could be used as an effective secondary field test to decrease the number of individuals falsely accused of possessing amphetamines.