Presentation at ACS Spring 2022 conference. Recently, there has been a flood of cannabidiol (CBD)-containing products, with divers marketing claims for a plethora of use cases. With this new market segment, regulatory oversight is still developing, and label claims of CBD concentration is often verifiable. CBD is unstable in solution and some CBD products are anecdotally reported to turn purple on storage; however, the decomposition products of CBD are mostly unknown. Delic Lab embarked on a long and painstaking hunt for those decomposition products, established their identity through complementary chemical methods and established reaction pathways between them. We will present our findings about common CBD oxidation products, who those are highly photochemically unstable and decomposes rapidly. Decomposition leads to a multitude of new cannabinoid derivatives.

1. Deep Purple: Identification of origin
of discolouration in CBD products
Brodie Thomson, Dr. Markus Roggen

2. Introduction
DELIC Labs is a research venture that seeks to add fundamental scientific
insight to the field of cannabis and mushroom production.
We seek to support the cannabis and mushroom industries by
establishing a centralized hub in Vancouver, BC, for collaborative
research focused on:
• Process Design
• Process Optimization
• Process Analytics
• Formulation Research

3. Collaborative Research
DELIC Labs collaborates with academic, industry and private groups
around the globe. Some highlights of those collaborations are:
• University of British Columbia, Vancouver
• Loyalist College, Belleville
• Via Innovations by Dr. Monica Vialpando
• Veridient Science by Dr. Linda Klumpers
Fundamental Collaboration

4. Research Topics
• Chemometrics and data analytics for process control and optimization
• Kinetic studies to understand mechanisms
• In-process analytics for process control
• Computational studies to understand mechanisms
• Process development, like crystallization
Fundamental Cannabis and Mushroom Chemistry

5. 3
Outline
- Purple CBD: Current understanding of its origin

6. 3
Outline
- Purple CBD: Current understanding of its origin
- Testing the current hypothesis

7. 3
Outline
- Purple CBD: Current understanding of its origin
- Testing the current hypothesis
- Identification of the compound responsible for the
formation

8. 3
Outline
- Purple CBD: Current understanding of its origin
- Testing the current hypothesis
- Identification of the compound responsible for the
formation
- Future work

9. CBD Degradation
- Global CBD sales predicted to exceed
US $19 billion by 2025.1
[1] Dobian, CBD Market to reach $19.5 billion by 2025, but only with FDA approval says top researcher. Forbes. July
28, 2021.
Available at https://www.forbes.com/sites/irisdorbian/?sh=2cd295c94bf8.
2

10. CBD Degradation
- Global CBD sales predicted to exceed
US $19 billion by 2025.1
- Current reports demonstrate differences
between advertised and measured CBD
concentrations.2
(1/3 of tested products contained <50% of
advertised CBD content)
[1] Dobian, CBD Market to reach $19.5 billion by 2025, but only with FDA approval says top researcher. Forbes. July
28, 2021.
Available at https://www.forbes.com/sites/irisdorbian/?sh=2cd295c94bf8.
[2] Liebling, J. P.; Clarkson, N. J.; Gibbs, B. W.; Yates, A. S.; O’Sullivan, S. E. An analysis of over-the-counter
cannabidiol
products in the United Kingdom. Cannabis Cannabinoid Res. 2020. doi: 10.1089/can.2019.0078.
4.5
3.2
0 1 2 3 4 5
Advertised
Measured
Percentage CBD (%)
Mean CBD content in tested
products
Adapted from Liebling et. al2
2

11. CBD Degradation
- Anecdotal evidence supports the
degradation of CBD solution with multiple
reports of CBD e-liquids and solutions
turning purple.
Sourced from Reddit3
[3] Reddit. CBD E-juice turned purple in the
tankhttps://www.reddit.com/r/Vaping/comments/e0z2ru/cbd_ejuice_turned_purple_in_the_ta
nk/ (Accessed March, 2022). 3

12. CBD Degradation
- Anecdotal evidence supports the
degradation of CBD solution with multiple
reports of CBD e-liquids and solutions
turning purple.
- Common conception that HU-331 and its
anion are the cause.
[3] Reddit. CBD E-juice turned purple in the
tankhttps://www.reddit.com/r/Vaping/comments/e0z2ru/cbd_ejuice_turned_purple_in_the_ta
nk/ (Accessed March, 2022).
Sourced from Reddit3
3

13. The Beam Test
- A classical colourimetric test for the identification of hashish using ethanolic KOH (5%).4
[4] Beam, W. Chemistry section in Fourth Report of Wellcome Tropical Research Laboratories, part B.
Khartoum, 1911; pp 25.
4

14. The Beam Test
- A classical colourimetric test for the identification of hashish using ethanolic KOH (5%).4
Cannabinoids
responsible for a
positive test result5
[4] Beam, W. Chemistry section in Fourth Report of Wellcome Tropical Research Laboratories, part B.
Khartoum, 1911; pp 25.
[5] Adams, R. Marijuana. Harvey Lecture. Bull. N. Y. Acad. Med. 1942, 18 (11), 705-730.
4

15. The Beam Test
- A classical colourimetric test for the identification of hashish using ethanolic KOH (5%).4
Example quinones
responsible for
the purple
colouration6
Cannabinoids
responsible for a
positive test result5
[4] Beam, W. Chemistry section in Fourth Report of Wellcome Tropical Research Laboratories, part B.
Khartoum, 1911; pp 25.
[5] Adams, R. Marijuana. Harvey Lecture. Bull. N. Y. Acad. Med. 1942, 18 (11), 705-730.
[6] Mechoulam, R.; Ben-Zvi, Z.; Gaoni, Y. Hashish-XIII. On the nature of the beam test. Tetrahedron,
1968, 5615-5624.
4

16. Tracking HU-331 Concentration
(65% PG, 30% VG, 5%
CBD)
5

17. Tracking HU-331 Concentration
(65% PG, 30% VG, 5%
CBD)
25 °C, 60% RH, O2
10 weeks
Light + dark storage
10 weeks
Dark storage
25 °C, 60% RH, O2
5

18. (65% PG, 30% VG, 5%
CBD)
25 °C, 60% RH, O2
10 weeks
Light + dark storage
10 weeks
Dark storage
25 °C, 60% RH, O2
[HU-331]
0.05 µg/g
Tracking HU-331 Concentration
5

19. (65% PG, 30% VG, 5%
CBD)
25 °C, 60% RH, O2
10 weeks
Light + dark storage
10 weeks
Dark storage
25 °C, 60% RH, O2
[HU-331]
0.05 µg/g
Tracking HU-331 Concentration
[HU-331]
116.03 μg/g
5

20. (65% PG, 30% VG, 5%
CBD)
25 °C, 60% RH, O2
10 weeks
Light + dark storage
10 weeks
Dark storage
25 °C, 60% RH, O2
[HU-331]
0.05 µg/g
Tracking HU-331 Concentration
[HU-331]
116.03 μg/g
[HU-331]
25.04 μg/g
5

21. (65% PG, 30% VG, 5%
CBD)
25 °C, 60% RH, O2
10 weeks
Light + dark storage
10 weeks
Dark storage
25 °C, 60% RH, O2
[HU-331]
0.05 µg/g
Tracking HU-331 Concentration
[HU-331]
116.03 μg/g
[HU-331]
25.04 μg/g
- CBD is oxidizing to HU-331
5

22. (65% PG, 30% VG, 5%
CBD)
25 °C, 60% RH, O2
10 weeks
Light + dark storage
10 weeks
Dark storage
25 °C, 60% RH, O2
[HU-331]
0.05 µg/g
Tracking HU-331 Concentration
[HU-331]
116.03 μg/g
[HU-331]
25.04 μg/g
- CBD is oxidizing to HU-331
- HU-331 is deprotonated
5

23. Tracking HU-331 Concentration
- CBD is oxidizing to HU-331
- HU-331 is deprotonated
6

24. Tracking HU-331 Concentration
- CBD is oxidizing to HU-331
- HU-331 is deprotonated
Where is the
base?
6

25. Tracking HU-331 Concentration
- CBD is oxidizing to HU-331
- HU-331 is deprotonated
Where is the
base?
𝒉𝒗
(65% PG, 30% VG, 5%
CBD)
6

26. Tracking HU-331 Concentration
- CBD is oxidizing to HU-331
- HU-331 is deprotonated
Where is the
base?
Light-driven deprotonation in neutral, protic media?
𝒉𝒗
(65% PG, 30% VG, 5%
CBD)
6

27. Tracking HU-331 Concentration
- CBD is oxidizing to HU-331
- HU-331 is deprotonated
Where is the
base?
𝒉𝒗
(65% PG, 30% VG, 5%
CBD)
Mass Chromatogram
6

28. Isolation of HU-331 and its Anion
7

29. Isolation of HU-331 and its Anion
Hexane
Water
Hexane
Water
7
Hexane
Water

30. Isolation of HU-331 and its Anion
Hexane
Water
7

31. Isolation of CBDHQ and its anion
1H NMR (300 MHz, DMSO-d6) 1H NMR (300 MHz, DMSO-d6)
8

32. Isolation of CBDHQ and its anion
1H NMR (300 MHz, DMSO-d6) 1H NMR (300 MHz, DMSO-d6)
8

33. Isolation of CBDHQ and its anion
1H NMR (300 MHz, DMSO-d6) 1H NMR (300 MHz, DMSO-d6)
8

34. Isolation of CBDHQ and its anion
9

35. Isolation of CBDHQ and its anion
(2 mg HU-331 in 0.6 mL DMSO-d6)
9

36. Isolation of CBDHQ and its anion
High absorption coefficient of HU-331 anion
suggests low concentrations can result in drastic
colouration in CBD solutions
(2 mg HU-331 in 0.6 mL DMSO-d6)
9

37. HU-331 Rate of Decomposition
- Is HU-331 degradation a light-driven process?
10

38. HU-331 Rate of Decomposition
- Is HU-331 degradation a light-driven process?
HU-331 (0.23 mg) +
dinitrobenzene
internal standard in
DMSO-d6 (0.5 mL)
10

39. R² = 0.9933
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
0 10 20 30 40 50 60
HU-331
Degradation
Relative
to
T
0
Time (min)
Light
Dark
Storage
Conditions
HU-331 Rate of Decomposition
- Is HU-331 degradation a light-driven process?
HU-331 (0.23 mg) +
dinitrobenzene
internal standard in
DMSO-d6 (0.5 mL)
10

40. R² = 0.9933
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
0 10 20 30 40 50 60
HU-331
Degradation
Relative
to
T
0
Time (min)
Light
Dark
Storage
Conditions
HU-331 Rate of Decomposition
- 45% reduction in [HU-331] after 60
minutes exposure to white light
- Is HU-331 degradation a light-driven process?
HU-331 (0.23 mg) +
dinitrobenzene
internal standard in
DMSO-d6 (0.5 mL)
10

41. Conditions Absorption Maximum (λmax)
CBD (30 mg) + HU-331 (1 mg) + Light in IPA (2 mL) 544 nm
CBD (30 mg) + HU-331 (1 mg) + Light in PG (2 mL) 545 nm
Identification of the Anion in CBD Solutions
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
380 430 480 530 580 630 680
Absorbance
(A)
Wavelength (nm)
CBD+HU-331+Light in IPA
CBD+HU-331+Light in PG
11

42. 0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
380 430 480 530 580 630 680
Absorbance
(A)
Wavelength (nm)
Deprotonated HU-331 in IPA
CBD+HU-331+Light in IPA
CBD+HU-331+Light in PG
Conditions Absorption Maximum (λmax)
CBD (30 mg) + HU-331 (1 mg) + Light in IPA (2 mL) 544 nm
CBD (30 mg) + HU-331 (1 mg) + Light in PG (2 mL) 545 nm
HU-331 anion in IPA 542 nm
Identification of the Anion in CBD Solutions
11

43. 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
380 430 480 530 580 630 680
Absorbance
(A)
Wavelength (nm)
HU-331
HU-331 and CBD at 0.5 mg mL-1 in IPA. Λmax of HU-331, 413 nm.
Role of HU-331 vs CBD
12

44. 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
380 430 480 530 580 630 680
Absorbance
(A)
Wavelength (nm)
CBD
HU-331
HU-331 and CBD at 0.5 mg mL-1 in IPA. Λmax of HU-331, 413 nm.
Role of HU-331 vs CBD
12

45. 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
380 430 480 530 580 630 680
Absorbance
(A)
Wavelength (nm)
CBD
HU-331 and CBD at 0.5 mg mL-1
in IPA. Λmax of HU-331, 413 nm.
448 nm light emission
Role of HU-331 vs CBD
13

46. 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
380 430 480 530 580 630 680
Absorbance
(A)
Wavelength (nm)
CBD
HU-331 and CBD at 0.5 mg mL-1
in IPA. Λmax of HU-331, 413 nm.
448 nm light emission
Role of HU-331 vs CBD
13

47. 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
380 430 480 530 580 630 680
Absorbance
(A)
Wavelength (nm)
CBD
HU-331 and CBD at 0.5 mg mL-1
in IPA. Λmax of HU-331, 413 nm.
448 nm light emission
Complete degradation of HU-331 in under 15
minutes
Role of HU-331 vs CBD
13

48. 448 nm light emission
Role of HU-331 vs CBD
14

49. 448 nm light emission
48 h
Role of HU-331 vs CBD
14

50. 448 nm light emission
HU-331 responsible for the
colouration
48 h
Role of HU-331 vs CBD
14

51. 448 nm light emission
HU-331 responsible for the
colouration
No HU-331 anion detected by
NMR or mass spectrometry
48 h
Role of HU-331 vs CBD
14

52. Presence of HU-331 anion?
48 h
15

53. Presence of HU-331 anion?
48 h
15
No HU-331 anion at high
concentration (>10 mg HU-331)

54. Conclusions
- HU-331 forms spontaneously within E-
liquids in the presence of oxygen.
- The formation of purple-coloured
CBD solutions is a result of a light-
driven degradation of HU-331.
- HU-331 anion likely not solely
responsible for the purple colour, if at
all.
- Degradation of HU-331 leads to
significant formation of novel products
inside CBD solutions.
16

55. Conclusions
- HU-331 forms spontaneously within E-
liquids in the presence of oxygen.
- The formation of purple-coloured
CBD solutions is a result of a light-
driven degradation of HU-331.
- HU-331 anion likely not solely
responsible for the purple colour, if at
all.
- Degradation of HU-331 leads to
significant formation of novel products
inside CBD solutions.
48 h
16

56. Conclusions
- HU-331 forms spontaneously within E-
liquids in the presence of oxygen.
- The formation of purple-coloured
CBD solutions is a result of a light-
driven degradation of HU-331.
- HU-331 anion likely not solely
responsible for the purple colour, if at
all.
- Degradation of HU-331 leads to
significant formation of novel products
inside CBD solutions.
48 h
16

57. Conclusions
- HU-331 forms spontaneously within E-
liquids in the presence of oxygen.
- The formation of purple-coloured
CBD solutions is a result of a light-
driven degradation of HU-331.
- HU-331 anion likely not solely
responsible for the purple colour, if at
all.
- Degradation of HU-331 leads to
significant formation of novel products
inside CBD solutions.
48 h
16

58. Future Work
48 h
- What mechanism follows HU-331’s photoexcitation that leads to the purple-coloured
solution?
17

59. Future Work
- What mechanism follows HU-331’s photoexcitation that leads to the purple-coloured
solution?
- What is causing the purple discolouration if not HU-331’s anion?
48 h
17

60. Acknowledgements
DELIC Labs:
Kendra Payne
Sajni Shah
Dr Eric Janusson
Dr Tom Dupree
Amanda Assen
Dingding Xuan
Ali Wasti
University of British Columbia:
Dr Glenn Sammis – Supervisor
Dr Tao Huan
Dr Maria Ezhova
18

61. Thank you! Questions?