I tried to do the amidation for activated carbon, by using some coupling agents, but it did not work. I used NHS/EDC, HATU-DIPEA, DCC with DMF as solvent. I analyzed the amount of nitrogen by using EDX analysis, but the still, the N percentage was less than 1%. I tried this method, because i didnt wan to use SOCl2 or COCl2 for acylation, as the reaction was too harsh. Could you please give any suggestions? Thank you.