N-Hexanoyl-L-Homoserine lactone-d 3 (C6-HSL-d 3 ) is deuterium labeled N-Hexanoyl-L-homoserine lactone. N-Hexanoyl-L-homoserine lactone is a short-chained N-acyl homoserine lactone (AHL). Diatoms are frequently found in association with Proteobacteria, many members of which employ cell-to-cell communication via AHLs in aquatic habitats.