Defense Date


Document Type

Directed Research Project

First Advisor

Rebecca Wagner, PhD


With the passing of the 2018 Farm Bill, which legalized hemp, law enforcement agencies and forensic laboratories needed a more efficient testing scheme to differentiate marijuana and hemp Cannabis plants. The validation of the 4-aminophenol chemical test and the subsequent analytical scheme allows for this differentiation to be performed. The evaluation of eighteen different cannabinoids, including acids, demonstrated that compounds with structures similar to tetrahydrocannabinol (THC) produced a blue result and compounds with structures similar to cannabidiol (CBD) produced a pink result. Several titration curves with varying concentrations of cannabinoids indicated a pink result when the THC concentration was less than the CBD concentration and a blue result when the THC concentration was greater than the CBD concentration. When the concentrations on THC and CBD were nearly equal, inconclusive results were obtained. The impact of other cannabinoids was also evaluated with a titration evaluation. Although not all cannabinoids produced the expected color result when analyzed, the cannabinoids are minor components of Cannabis plant material and would not be expected to be in high enough concentrations to skew the color results. Preprocessed, processed, and casework plant material samples were used to validate the 4-aminophenol chemical test. The remainder of the newly proposed analytical scheme, including thin-layer chromatography and gas-chromatography-flame ionization detection-mass spectrometry was used to corroborate this validation. The validation of a high performance liquid chromatograph-diode array detector method to fully quantitate samples is still in progress. The 4-aminophenol chemical test also has potential as a viable screening method for oil and food samples as well, but further validation is required.


© The Author(s)

Is Part Of

VCU Master of Science in Forensic Science Directed Research Projects

Date of Submission



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