Table 1.
Comparison of (a) 233 volatiles found in this study emitted from marijuana, including those emitted through-packaging with (b) volatiles previously reported as ‘signature’ compounds of marijuana in headspace.
Fig 1.
Effects of sampling time, as total ion chromatograms (TICs), of volatiles emitted from marijuana.
Orange signal represents volatiles emitted from 1 g desiccated marijuana, loose in a 473 mL glass jar. Black signal represents volatiles emitted from 1 g desiccated marijuana, in a plastic zip-top bag, in a 473 mL glass jar. The boxed retention time widow highlights where volatiles, from previously published articles, would elute from the analytical column of the MDGC-MS-O. The set of 3 TICs represent volatiles extracted over (A) 5 min, (B) 1 h, and (C) 68 h resulting 20, 54, and 101 chromatographic peaks (orange signal), and 25, 39, 108 chromatographic peaks (black signal), respectively. See S2 and S3 Tables for the complete summary of identified compounds.
Fig 2.
Simultaneous chemical and sensory analysis of volatiles emitted into headspace, through a duffel bag, and captured by SPME over 68 h.
Total ion chromatogram (black) and aromagram, (red, inverted) of VOC emitted from marijuana in a duffel bag. An 85 μm Carboxen/PDMS SPME fiber was exposed to headspace over the duffel bag, within an overturned glass jar to capture emitted volatiles for 68 h (see S2 Fig). A total of 53 aroma events and 178 compounds were recorded (S8 Table). Aroma events # 12, 15, 46, and 51 were recorded as a ‘characteristic’ smell (i.e. (*) the aromas that most represent the overall aroma of marijuana). Outlined boxes signify (A) big chemical peak detected, smell detected; (B) chemical peak detected, no smell detected; (C) Small or no chemical peak detected, smell detected. Zoomed boxes A, B, and C identify chemical peaks and aromas.
Fig 3.
Dot plot reporting shift in rank of volatiles emitted from marijuana by surrogate concentration vs. calculated OAV.
Markers represent VOC emitted from all marijuana samples and extracted from headspace by SPME over 68 h at room temperature. Compounds are ranked by surrogate concentration vs. calculated OAV using standardized ODT in air from Devos, et al. (1990) [35]. Data representing bagged and loose marijuana sampled for 68 h are similar to S5 Fig. Rank value (horizontal-axis) of 1 indicates low surrogate concentration or low OAV; rank of 60 indicates high surrogate concentration or high OAV. The general trend is a shift in rank between surrogate concentration and odor activity value. Nerol has a rank of 6 by surrogate concentration and has a rank of 51 by OAV (bottom red box); α-pinene has a rank of 49 by surrogate concentration and has a rank of 25 by OAV (top red box). Values of rank for each VOC are given in S6 Table. Compounds in the black box highlight VOC that were detected in fresh marijuana and permeated through a duffel bag, not detected or permeated in desiccated marijuana.
Fig 4.
Compounds with high odor impact are not always the most abundant in concentration.
Horizontal axis is peak area counts (PAC) of mass detector response on logarithmic scale, assuming equal response for all compounds. Vertical axis is calculated OAV (Eq 1) for each compound. Highly odorous compounds emitted from loose marijuana (blue circles) and through packaging (yellow triangles) over 68 h at room temperature are 1) Benzaldehyde, 2) Myrcene, 3) Decanal, 4) Heptanal, 5) Methyl anthranilate, 6) Octanal, 7) Hexanal, 8) Methylisohexenyl ketone, 9) Linalool, 10) β-caryophyllene, 11) α-humelene, 12) Acetic acid. Highly odorous compounds emitted from fresh evidence of marijuana through a duffel bag (black diamonds) over 68 h at room temperature are A) Nonanal, B) Decanol, C) o-cymene, D) Isobutyraldehyde, E) 1-chloroacetophenone, F) Nerol, G) Propylamine, H) o-guaiacol, I) Linalyl acetate, J) Methyl anthranilate, K) Benzaldehyde, L) Limonene.