The Miniaturization, Optimization, and Chemometric Evaluation of Colorimetric Tests for the Indication of Hemp-Type and Marijuana-Type Cannabis

Authors

Alexander G. Acosta, Florida International UniversityFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Chemistry

First Advisor's Name

Jose R. Almirall

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Bruce McCord

Second Advisor's Committee Title

Committee Member

Third Advisor's Name

Martin Quirke

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

Anthony DeCaprio

Fourth Advisor's Committee Title

Committee Member

Fifth Advisor's Name

Shekhar Bhansali

Fifth Advisor's Committee Title

Committee Member

Keywords

Cannabis, Hemp, Marijuana, Color Tests, FBBB, 4-AP, LDA, SIMCA

Date of Defense

10-26-2022

Abstract

Hemp is defined as Cannabis Sativa containingCannabis Sativa with containing ≥0.3% THC and is federally illicit. A colorimetric test known to distinguish between THC and CBD, 4-Aminophenol (4-AP) was miniaturized and optimized to improve sensitivity, specificity, and applicability in the field. For the first time, a fluorescence test is combined with a colorimetric test using Fast Blue BB (FBBB) and Red, Green, Blue (RGB) color codes were obtained for the fluorophore/chromophore formed and used to build chemometric models to determine the utility of both the new miniaturized 4-AP and FBBB tests.

The FBBB test was miniaturized to a 3.5 mm Planar Solid-Phase Microextraction (PSPME) substrate form factor. THC reacts with FBBB to form and red color and fluoresces red under 480 nm light while CBD forms an orange color and does not fluoresce. Linear Discriminant Analysis (LDA) of 25 cannabis samples showed that FBBB is sensitive and specific when differentiating hemp from THC-rich marijuana (THC:CBD>2) when using color and fluorescence. 4-AP is known to form a pink color with hemp and a blue color with marijuana. This test was miniaturized to a 6.35 mm silicone treated filter paper substrate form factor. Authentic cannabis samples (n=192 representing both hemp and marijuana) were analyzed using both the 4-AP and FBBB tests. LDA and Data Driven-Soft Independent Modeling of Class Analogies (DD-SIMCA) models show that both tests differentiate between THC-rich marijuana with ~ 95% accuracy when used in combination. Characterization studies of the products of the THC and CBD reactions with 4-AP are also described for the first time using mass spectrometry. This work demonstrates that the FBBB and 4-AP colorimetric test methods are suitable for field analysis to distinguish hemp-type and marijuana-type cannabis.

Identifier

FIDC010988

ORCID

0000-0001-9725-0097

Previously Published In

Acosta, A.; Almirall, J. Differentiation between Hemp-Type and Marijuana-Type Cannabis Using the Fast Blue BB Colorimetric Test. Forensic Chemistry 2021, 26, 100376.

Acosta, A., Li, L, Weaver, M., Perr, J., Capote, R., Almirall, J. Validation of a combined Fast Blue BB and 4-Aminophenol colorimetric test for the Indication between Hemp-type and Marijuana-type Cannabis. Forensic Chemistry 2022, 31, 100448

Recommended Citation

Acosta, Alexander G., "The Miniaturization, Optimization, and Chemometric Evaluation of Colorimetric Tests for the Indication of Hemp-Type and Marijuana-Type Cannabis" (2022). FIU Electronic Theses and Dissertations. 5221.
https://digitalcommons.fiu.edu/etd/5221