Plastic pollution transcends marine protected area boundaries in the eastern tropical and south-eastern Pacific.

The Eastern Tropical and South-Eastern Pacific region is of global biodiversity importance. At COP26, the governments of Costa Rica, Panama, Colombia, and Ecuador committed to the expansion of existing MPAs to create a new Mega MPA, safeguarding the Eastern Tropical Pacific Marine Corridor. It offers a profound step forward in conservation efforts but is not specifically designed to protect against the more diffuse anthropogenic threats, such as plastic pollution. We combine published data with our own unpublished records to assess the abundance and distribution of plastic pollution in the region. Macro- and microplastic concentrations varied markedly and were not significantly different when comparing areas inside and outside existing MPA boundaries. These findings highlight the diffuse and complex nature of plastic pollution and its ubiquitous presence across MPA boundaries. Understanding the sources and drivers of plastic pollution in the region is key to developing effective solutions.

Enantiomeric discrimination of isoxazoline fused ß-amino acid derivatives using (18-crown-6)-2,3,11,12-tetracarboxylic acid as a chiral NMR solvating agent.

(18-Crown-6)-2,3,11,12-tetracarboxylic acid is a useful chiral NMR solvating agent for isoxazoline-fused ß-amino acid derivatives. Isoxazoline substrates are analyzed as their hydrochloride salts in methanol-d(4). The crown ether and substrate associate through the formation of three hydrogen bonds between the protonated amine and crown ether oxygen atoms. Enantiomeric discrimination is observed for two or more resonances of every substrate. At least one of these resonances is free of overlap with other resonances in the spectrum and has large enough enantiomeric discrimination to enable the determination of enantiomeric purity. 2D COSY methods can be used to identify additional resonances that exhibit enantiomeric discrimination in the NMR spectrum.