The ALMA-QUARKS survey: Extensive detection of acetamide in multiple high-mass star-forming regions

Acetamide (CH 3 CONH 2 ), a key interstellar amide and a methyl derivative of formamide (NH 2 CHO), has rarely been detected, limiting insights into its prebiotic relevance. We present the first systematic survey of acetamide toward 52 hot molecular cores using ALMA Band 6 data. We have detected acetamide in ten cores, markedly expanding the inventory of known emitters. The derived column densities of acetamide range from (2.5 ± 0.9) × 10 14 to (1.5 ± 0.6) × 10 16 cm −2 , compared to formamide’s (1.1 ± 0.1) × 10 15 to (6.9 ± 0.4) × 10 16 cm −2 . The nearly constant abundance ratios (~3–9) and strong abundance correlation between the two amides across sources suggest a chemically linked formation pathway, likely on grain surfaces. The presence of peptide-like molecules in these regions implies that complex organic species can survive star formation processes, offering a potential pathway toward prebiotic chemistry. These findings constrain the dominant grain-surface formation routes of acetamide, confirm its broader prevalence in high-mass star-forming regions, and underscore the importance of targeted amide surveys in tracing the chemical evolution toward prebiotic complexity.