Identifying potential antioxidant compounds in NaOH extracts of UK soils and vegetation by untargeted mass spectrometric screening

► AOC of NaOH extracts of soil and vegetation were measured by two methods. ► Py-FIMS proposed groups of compounds present in both soil and vegetation. ► Some mass signals linked to AOC appeared in all extracts. ► Evidence suggests survival of some antioxidants during humification. ► Non-polar compounds contribute in large proportions to AOC in soils and vegetation.