A Raman spectral reference library of potential anthropogenic and biological ocean polymers.

Microplastics have been extensively documented in marine ecosystems and food webs with devastating impacts. To solve this global crisis, identifying the polymer composition is key for resolving the material origin, geographic source, and ecosystem life cycle of ocean plastics. Visually based techniques, importantly, are not diagnostic. Raman spectroscopy is an increasingly preferred identification method for its accuracy and reduced likelihood of misinterpretation, though it can be inaccessible due to cost of paywalled spectral libraries and availability of relevant polymer spectra for comparison. Here, we provide an open-access reference library of high-quality, broad-spectrum Raman spectra of major polymer categories germane to marine environments. The library includes high-quality spectra from: (a) pristine anthropogenic polymers newly sourced from manufacturers (n = 40), (b) weathered anthropogenic polymers collected from used consumer, beachcast, agricultural, and fishery sources (n = 22), and (c) biological polymers representing diverse marine taxa, trophic levels, and tissues (n = 17). We hope this reference library can help this rapidly expanding scientific community and facilitate progress in the global plastic pollution crisis.

Quantitative analysis of cannabinoids using benchtop NMR instruments.

The quantification of cannabinoids is an essential part of cannabis profiling and testing, whether for medical or recreational use. As regulatory bodies continue to increase testing requirements for these products, it is crucial that alternative and effective analytical methods be developed. Herein, we describe the use of benchtop NMR instruments for the quantification of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in a variety of cannabis concentrates and compare the values to those obtained using HPLC, the most common approach for the quantification of cannabinoids. Based on the discrepancies observed in test values from different laboratories using only HPLC, the value of orthogonal testing methods has been identified and is increasingly desired.

Engineering case report. Toluene and methyl ethyl ketone exposure from a commercially available contact adhesive.

A maintenance worker became ill after working indoors over the course of 3 days with a commercially available contact adhesive containing toluene and methyl ethyl ketone. Respiratory protection or local exhaust ventilation was not used. The worker subsequently suffered from numerous medical symptoms including tremors and elevated blood pressure. Magnetic resonance imaging documented the occurrence of encephalopathy. The worker has alleged that the cause of these effects was exposure to the vapors from the contact adhesive. The objective of this study was to characterize/estimate the level of the worker's exposure by obtaining air samples in an exposure chamber while performing similar activities under similar conditions. We found that the worker may have been exposed to approximately 159 ppm toluene and 58 ppm methyl ethyl ketone 8-hr time-weighted averages for 8 hr of adhesive application. The maximum 15-min average exposures were 233 ppm toluene and 85 ppm methyl ethyl ketone.