SEARCH Articles Figures Tables 2- Phosphonobutane-1,2,4-tricarboxylic acid 2-Phosphonobutane-1,2,4-tricarboxylic acid PBTC) 2-Phosphonobutane-l,2,4-tricarboxylic 2-Phosphonobutane-l,2,4-tricarboxylic acid Tricarboxylates