No abstract

Cannabis consumer products are a $4.6 billion industry in the U.S. that is projected to exceed $14 billion by 2025. Despite an absence of U.S. Food and Drug Administration (FDA) regulation or clinical data, thousands of nutraceuticals, topical consumer products, and beauty products claim benefits of hemp or cannabidiol. However, a lack of required quality control measures prevents consumers from knowing the true concentration or purities of cannabis-labeled products. Thirteen over-the-counter consumer products were examined for the presence of cannabidiol (CBD), cannabinol (CBN), Δ9-tetrahydrocannabinol (THC), cannabidiolic acid (CBDA), and Δ9-tetrahydrocannabinolic acid A (THCA). Additionally, the efficacy of topical applications was investigated using a porcine skin model, in which particle size and zeta potential relate to skin permeability. Skin permeation was correlated to particle size and relative stability in skin-like conditions but not directly related to the CBD content, suggesting that topical products can be designed to enhance overall skin permeation. Of the products analyzed, all products have some traceable amount of cannabinoids, while seven products had multiple cannabinoids with quantifiable amounts. Overall, the need for further regulation is clear, as most products have apparent distinctions between their true and labeled contents.

Recently, topical products advertising cannabinoid ingredients have gained popularity. Consumers are seeing an increase of commercial products containing ingredients from hemp oil to cannabidiol (CBD) due to health benefit claims. Cosmetic products containing cannabinoids are currently not regulated at the federal level. A laboratory experiment for undergraduate students in analytical and organic chemistry courses was developed utilizing high-performance liquid chromatography (HPLC) analysis to identify and quantify cannabinoid compounds present in commercially available topical products. Students used calibration curves of a cannabinoid standard to quantify cannabinoids present in the CBD products. By comparing relative retention times of the cannabinoids present in the standard, students were able to identify the cannabinoids present in their lotion sample. Responsibilities and assignments suit students ranging from introductory to advanced chemistry courses. Students are provided the opportunity to extract and experimentally calculate the amount of CBD and compare to the amounts advertised on product labels. Results showed that the average CBD amounts were higher than advertised for all lotions except CBDFx when analyzed using HPLC. This experiment can be modified to incorporate a variety of different topical water-based products including hair products, shampoo, and other cosmetics. Furthermore, an analysis of samples using gas chromatography mass spectrometry (GC-MS) was also developed to adapt to instrument availability.

The building of van der Waals heterostructures and the decoration of 2D materials with organic molecules share a common goal: to obtain ultrathin materials with tailored properties. Performing controlled chemistry on van der Waals heterostructures would add an extra level of complexity, providing a pathway towards 2D-2D-0D mixed-dimensional heterostructures. Here we show that thiol-ene-like “click” chemistry can be used to decorate franckeite, a naturally occurring van der Waals heterostructure, with maleimide reagents. ATR-IR and NMR analyses corroborate the Michael addition mechanism via the formation of a S-C covalent bond, while Raman and HR-TEM show that the SnS₂-PbS alternating structure of franckeite is preserved, and suggest that SnS₂reacts preferentially, which is confirmed through XPS. We illustrate how this methodology can be used to add functional molecular moieties by decorating franckeite with porphyrins. UV-vis-NIR spectroscopy confirms that the chromophore remains operative and shows negligible electronic interactions with franckeite in the ground state, while its fluorescence is strongly quenched upon photoexcitation.

No abstract

With the advancements in broad-spectrum sunscreens and the recent bans on benzene-based sunscreens due to their environmental toxicity, there has been a push toward broad-spectrum sunscreens containing inorganic active ingredients. In this study, a procedure was developed to analyze the particle size and size distribution of inorganic active ingredients, titanium dioxide (TiO2) and/or zinc oxide (ZnO), of sunscreens with sun protection factor (SPF) values ranging from 15 to 50 using dynamic light scattering (DLS). These inorganic components are often engineered as nanoparticles in order to reduce visibility on the skin and retain UV scattering. Research suggests that the use of smaller nanoparticles to increase the efficacy of the inorganic filters may also be toxic to humans if it becomes permeable to the skin. This methodology allowed undergraduate students to work hands-on with particle sizing and compare sunscreen samples to nanopowder and dispersion standards using the effect of the hydrodynamic diameter. Students found that, due to agglomeration, the particle sizes for the nanopowder standards could exceed the manufacture’s labeled size when dispersed in solution, which they then compared with their sunscreen data. The results also showed that some sunscreens had two distinct layers at the end of sample preparation, which could be correlated to the matrix components within the sunscreens. This study is intended for undergraduate analytical students and can be altered using the potential variations and scanning electron microscopy (SEM) with electron dispersive spectroscopy (EDS) to create a more challenging upper-level lab and allow for instrumentation comparisons.

and Aakriti Damai, is available. There was an extra zero added on page 5, Sample CalculationsKEY. In the calculation, instead of 6250 mg/L (ppm) in two places, it should read 625 mg/L (ppm) in both instances.

<p>The building of van der Waals heterostructures and the decoration of 2D materials with organic molecules share a common goal: to obtain ultrathin materials with tailored properties. Performing controlled chemistry on van der Waals heterostructures would add an extra level of complexity, providing a pathway towards 2D‑2D-0D mixed-dimensional heterostructures. Here we show that thiol-ene-like “click” chemistry can be used to decorate franckeite, a naturally occurring van der Waals heterostructure with maleimide reagents. ATR-IR and NMR analyses corroborate the Michael addition mechanism via the formation of a S–C covalent bond, while Raman and HR-TEM show that the SnS₂-PbS alternating structure of franckeite is preserved, and suggest that SnS₂ reacts preferentially, which is confirmed through XPS. We illustrate how this methodology can be used to add functional molecular moieties by decorating franckeite with porphyrins. UV-vis-NIR spectroscopy confirms that the chromophore ground state remains operative, showing negligible ground-state interactions with the franckeite. Excited-state interactions across the hybrid interface are revealed. Time-resolved photoluminescence confirms the presence of excited-state de-activation in the linked porphyrin ascribed to energy transfer to the franckeite.</p>