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

Acetamide (CH3CONH2), a key interstellar amide and a methyl derivative of formamide (NH2CHO), 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) × 1014 to (1.5 ± 0.6) × 1016 cm−2, compared to formamide’s (1.1 ± 0.1) × 1015 to (6.9 ± 0.4) × 1016 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.