Title: Optical and spectroscopic characterization of crystalline structures in cannabis extracts
Abstract
Marijuana and hemp represent two broad classes ofCannabis sativaplants that are distinguished based on the concentration of the psychoactive cannabinoid delta‐9‐tetrahydrocannabinol (Δ9‐THC). In this work, solvent extracts derived from marijuana and hemp were characterized using optical and spectroscopic techniques. The crystalline components of the solvent extracts were first analyzed using polarized light microscopy to determine optical properties, namely, crystal system, optical sign, and principle refractive indices. Crystals from the marijuana‐derived extracts exhibited an orthorhombic crystal system and were optically negative, with nβbetween 1.6320 and 1.6330 ± 0.0002. In contrast, crystals from hemp‐derived extracts exhibited a monoclinic crystal system and were optically positive, with nβbetween 1.600 and 1.6040 ± 0.0002. Crystals were further distinguished through infrared spectroscopy, which highlighted structural differences between the two sample types, primarily based on differences in O‐H stretching. Finally, single‐crystal X‐ray diffraction was used to definitively identify the crystalline components, confirming the presence of tetrahydrocannabinolic acid in marijuana‐derived extracts and cannabidiol in hemp‐derived extracts. Given the differences in crystal structure identified between marijuana‐derived and hemp‐derived solvent extracts, optical characterization provides a screening method to differentiate visually similar samples prior to confirmatory analysis.
Hemp and marijuana are the two major varieties ofCannabis sativa. While both contain Δ9-tetrahydrocannabinol (THC), the primary psychoactive component ofC. sativa, they differ in the amount of THC that they contain. Presently, U.S. federal laws stipulate thatC. sativacontaining greater than 0.3% THC is classified as marijuana, while plant material that contains less than or equal to 0.3% THC is hemp. Current methods to determine THC content are chromatography-based, which requires extensive sample preparation to render the materials into extracts suitable for sample injection, for complete separation and differentiation of THC from all other analytes present. This can create problems for forensic laboratories due to the increased workload associated with the need to analyze and quantify THC in allC. sativamaterials.
Method
The work presented herein combines direct analysis in real time—high-resolution mass spectrometry (DART-HRMS) and advanced chemometrics to differentiate hemp and marijuana plant materials. Samples were obtained from several sources (e.g., commercial vendors, DEA-registered suppliers, and the recreationalCannabismarket). DART-HRMS enabled the interrogation of plant materials with no sample pretreatment. Advanced multivariate data analysis approaches, including random forest and principal component analysis (PCA), were used to optimally differentiate these two varieties with a high level of accuracy.
Results
When PCA was applied to the hemp and marijuana data, distinct clustering that enabled their differentiation was observed. Furthermore, within the marijuana class, subclusters between recreational and DEA-supplied marijuana samples were observed. A separate investigation using the silhouette width index to determine the optimal number of clusters for the marijuana and hemp data revealed this number to be two. Internal validation of the model using random forest demonstrated an accuracy of 98%, while external validation samples were classified with 100% accuracy.
Discussion
The results show that the developed approach would significantly aid in the analysis and differentiation ofC. sativaplant materials prior to launching painstaking confirmatory testing using chromatography. However, to maintain and/or enhance the accuracy of the prediction model and keep it from becoming outdated, it will be necessary to continue to expand it to include mass spectral data representative of emerging hemp and marijuana strains/cultivars.
Cs2SnI6perovskite displays excellent air stability and a high absorption coefficient, promising for photovoltaic and optoelectronic applications. However, Cs2SnI6‐based device performance is still low as a result of lacking optimized synthesis approaches to obtain high quality Cs2SnI6crystals. Here, a new simple method to synthesize single crystalline Cs2SnI6perovskite at a liquid–liquid interface is reported. By controlling solvent conditions and Cs2SnI6supersaturation at the liquid–liquid interface, Cs2SnI6crystals can be obtained from 3D to 2D growth with controlled geometries such as octahedron, pyramid, hexagon, and triangular nanosheets. The formation mechanisms and kinetics of complex shapes/geometries of high quality Cs2SnI6crystals are investigated. Freestanding single crystalline 2D nanosheets can be fabricated as thin as 25 nm, and the lateral size can be controlled up to sub‐millimeter regime. Electronic property of the high quality Cs2SnI62D nanosheets is also characterized, featuring a n‐type conduction with a high carrier mobility of 35 cm2V−1s−1. The interfacial reaction‐controlled synthesis of high‐quality crystals and mechanistic understanding of the crystal growth allow to realize rational design of materials, and the manipulation of crystal growth can be beneficial to achieve desired properties for potential functional applications.
Song, L.; Pathipaka, S.B.; Leese, J.D.; Chao, M.; Collins, T.; Westein, J.P.(
, 2020 American Academy of Forensic Sciences Annual Scientific Meeting)
After attending this presentation, attendees will gain knowledge in the strategy to achieve high-throughput and simultaneous analysis of cannabinoids and appreciate a validated LC-UV method for analysis of twelve cannabinoids in hemp oil.
This presentation will first impact the forensic science community by introducing three fast LC separations of twelve cannabinoids that can be used with either UV or mass spectrometric (MS) detection. It will further impact the forensic science community by introducing a validated LC-UV method for high-throughput and simultaneous analysis of twelve cannabinoids in hemp oil, which can be routinely used by cannabis testing labs.
In recent years, the use of products of Cannabis sativa L. for medicinal purposes has been in a rapid growth, although their preparation procedure has not been clearly standardized and their quality has not been well regulated. To analyze the therapeutic components, i.e. cannabinoids, in products of Cannabis sativa L., LC-UV has been frequently used, because LC-UV is commonly available and usually appropriate for routine analysis by the cannabis growers and commercial suppliers. In the literature, a few validated LC-UV methods have been described. However, so far, all validated LC-UV methods only focused in the quantification of eleven or less cannabinoids. Therefore, a method able to simultaneously analyze more cannabinoids in a shorter run time is still in high demand, because more and more cannabinoids have been isolated and many of them have shown medicinal properties.
In this study, the LC separation of twelve cannabinoids, including cannabichromene (CBC), cannabidiolic acid (CBDA), cannabidiol (CBD), cannabidivarinic acid (CBDVA), cannabidivarin (CBDV), cannabigerolic acid (CBGA), cannabigerol (CBG), cannabinol (CBN), delta-8 tetrahydrocannabinol (Δ8-THC), delta-9 tetrahydrocannabinolic acid A (Δ9-THCA A), delta-9 tetrahydrocannabinol (Δ9-THC), and tetrahydrocannabivarin (THCV), has been systematically optimized using a Phenomenex Luna Omega 3 µm Polar C18 150 mm × 4.6 mm column with regard to the effects of the type of organic solvent, i.e. methanol and acetonitrile, the content of the organic solvent, and the pH of the mobile phase. The optimization has resulted in three LC conditions at 1.0 mL/minute able to separate the twelve cannabinoids: 1) a mobile phase consisting of water and methanol, both containing 0.1% formic acid (pH 2.69), with a gradient elution at 75% methanol for the first 3 minutes and then linearly increase to 100% methanol at 12.5 minutes; 2) a mobile phase consisting of water and 90% (v/v) acetonitrile in water, both containing 0.1% formic acid and 20 mM ammonium formate (pH 3.69), with an isocratic elution at 75% acetonitrile for 14 minutes; and 3) a mobile phase consisting of water and 90% (v/v) acetonitrile in water, both containing 0.03% formic acid and 20 mM ammonium formate (pH 4.20), with an isocratic elution at 75% acetonitrile for 14 minutes.
In order to demonstrate the effectiveness of the achieved LC separations, a LC-UV method is further validated for the high-throughput and simultaneous analysis of twelve cannabinoids. The method used the mobile phase at pH 3.69, which resulted in significant improvement in throughput compared to other validated LC-UV methods published so far. The method used flurbiprofen as the internal standard. The linear calibration range of all the cannabinoids were between 0.1 to 25 ppm with R2≥0.9993. The LOQ (S/N=10) of the cannabinoids was between 17.8 and 74.2 ppb. The validation used a hemp oil containing 3.2 wt% CBD and no other cannabinoids, which was reported by the vendor with a certificate of analysis, as the matrix to prepare control samples: the hemp oil was first extracted using liquid-liquid extraction (LLE) with methanol; cannabinoids were then spiked into the extract at both 0.5 ppm and 5 ppm level. Afterwards, the recovery, precision (%RSD) and accuracy (%Error) of the control samples were assessed and the results met the requirements by the ISO/IEC 17025 and ASTM E2549-14 guidelines.
Karki, Santosh; Meher, Anil K.; Inutan, Ellen D.; Pophristic, Milan; Marshall, Darrell D.; Rackers, Kevin; Trimpin, Sarah; McEwen, Charles N.(
, Rapid Communications in Mass Spectrometry)
Rationale
Successful coupling of a multi‐ionization automated platform with commercially available mass spectrometers provides improved coverage of compounds in complex mixtures through implementation of new and traditional ionization methods. The versatility of the automated platform is demonstrated through coupling with mass spectrometers from two different vendors. Standards and complex biological samples were acquired using electrospray ionization (ESI), solvent‐assisted ionization (SAI) and matrix‐assisted ionization (MAI).
Methods
The MS™ prototype automated platform samples from 96‐ or 384‐well plates as well as surfaces. The platform interfaces with Thermo Fisher Scientific mass spectrometers by replacement of the IonMax source, and on Waters mass spectrometers with additional minor source inlet modifications. The sample is transferred to the ionization region using a fused‐silica or metal capillary which is cleaned between acquisitions using solvents. For ESI and SAI, typically 1 μL of sample solution is drawn into the capillary tube and for ESI slowly dispensed near the inlet of the mass spectrometer with voltage placed on the delivering syringe barrel to which the tubing is attached, while for SAI the sample delivery tubing inserts into the inlet without the need for high voltage. For MAI, typically, 0.2 μL of matrix solution is drawn into the syringe before drawing 0.1 μL of the sample solution and dispensing to dry before insertion into the inlet.
Results
A comparison study of a mixture of angiotensin I, verapamil, crystal violet, and atrazine representative of peptides, drugs, dyes, and herbicides using SAI, MAI, and ESI shows large differences in ionization efficiency of the various components. Solutions of a mixture of erythromycin and azithromycin in wells of a 384‐microtiter well plate were mass analyzed at the rate ofca1 min per sample using MAI and ESI. In addition, we report the analysis of bacterial extracts using automated MAI and ESI methods. Finally, the ability to perform surface analysis with the automated platform is also demonstrated by directly analyzing dyes separated on a thin‐layer chromatography (TLC) plate and compounds extracted from the surface of a beef liver tissue section.
Conclusions
The prototype multi‐ionization automated platform offers solid matrix introduction used with MAI, as well as solution introduction using either ESI or SAI. The combination of ionization methods extends the types of compounds which are efficiently ionized and is especially valuable with complex mixtures as demonstrated for bacterial extracts. While coupling of the automated multi‐ionization platform to Thermo and Waters mass spectrometers is demonstrated, it should be possible to interface it with most commercial mass spectrometers.
We report results of the optical properties of Dy-doped CsPbCl3and KPb2Cl5bulk crystals for potential applications in yellow solid-state laser development. The crystals were synthesized from purified starting materials and melt-grown by vertical Bridgman technique. Optical transmission measurements revealed characteristic absorption bands from intra-4f transitions of Dy3+ions. Direct optical excitation at 455 nm (6H15/2→4I15/2) resulted in dominant yellow emission bands at ∼575 nm from the4F9/2excited state of Dy3+ions. In addition, both crystals exhibited weaker emission lines in the blue (∼483 nm) and red (∼670 nm) regions. The peak emission-cross sections for the yellow transition (4F9/2→6H13/2) were determined to be ∼0.22 × 10−20cm2for Dy: CsPbCl3(λpeak = 576.5 nm) and ∼0.59 × 10−20cm2for Dy: KPb2Cl5(λpeak = 574.5 nm). The spectral properties and decay dynamics of the4F9/2excited state were evaluated within the Judd-Ofelt theory to predict total radiative decay rates, branching ratios, and emission quantum efficiencies.
Abraham, Otyllia R., and Waddell Smith, Ruth. Optical and spectroscopic characterization of crystalline structures in cannabis extracts. Journal of Forensic Sciences 67.2 Web. doi:10.1111/1556-4029.14940.
Abraham, Otyllia R., & Waddell Smith, Ruth. Optical and spectroscopic characterization of crystalline structures in cannabis extracts. Journal of Forensic Sciences, 67 (2). https://doi.org/10.1111/1556-4029.14940
Abraham, Otyllia R., and Waddell Smith, Ruth.
"Optical and spectroscopic characterization of crystalline structures in cannabis extracts". Journal of Forensic Sciences 67 (2). Country unknown/Code not available: Wiley-Blackwell. https://doi.org/10.1111/1556-4029.14940.https://par.nsf.gov/biblio/10305457.
@article{osti_10305457,
place = {Country unknown/Code not available},
title = {Optical and spectroscopic characterization of crystalline structures in cannabis extracts},
url = {https://par.nsf.gov/biblio/10305457},
DOI = {10.1111/1556-4029.14940},
abstractNote = {Abstract Marijuana and hemp represent two broad classes ofCannabis sativaplants that are distinguished based on the concentration of the psychoactive cannabinoid delta‐9‐tetrahydrocannabinol (Δ9‐THC). In this work, solvent extracts derived from marijuana and hemp were characterized using optical and spectroscopic techniques. The crystalline components of the solvent extracts were first analyzed using polarized light microscopy to determine optical properties, namely, crystal system, optical sign, and principle refractive indices. Crystals from the marijuana‐derived extracts exhibited an orthorhombic crystal system and were optically negative, with nβbetween 1.6320 and 1.6330 ± 0.0002. In contrast, crystals from hemp‐derived extracts exhibited a monoclinic crystal system and were optically positive, with nβbetween 1.600 and 1.6040 ± 0.0002. Crystals were further distinguished through infrared spectroscopy, which highlighted structural differences between the two sample types, primarily based on differences in O‐H stretching. Finally, single‐crystal X‐ray diffraction was used to definitively identify the crystalline components, confirming the presence of tetrahydrocannabinolic acid in marijuana‐derived extracts and cannabidiol in hemp‐derived extracts. Given the differences in crystal structure identified between marijuana‐derived and hemp‐derived solvent extracts, optical characterization provides a screening method to differentiate visually similar samples prior to confirmatory analysis.},
journal = {Journal of Forensic Sciences},
volume = {67},
number = {2},
publisher = {Wiley-Blackwell},
author = {Abraham, Otyllia R. and Waddell Smith, Ruth},
}
Warning: Leaving National Science Foundation Website
You are now leaving the National Science Foundation website to go to a non-government website.
Website:
NSF takes no responsibility for and exercises no control over the views expressed or the accuracy of
the information contained on this site. Also be aware that NSF's privacy policy does not apply to this site.
