... .5 maxPhosphoric acid(as PO43-)%0.2 maxDensity (20°C) g/cm31.27 minpH(1% water solution)1.5~2.0Fe ppm10.0 maxChloride ppm10 ... , flush with water.Synonyms:PBTCA;PBTC;PHOSPHONOBUTANE TRICARBOXYLIC ACID;2-Phosphonobutane -1,2,4-Tricarboxylic Acid;2-Phosphonobutane-1,2,4-tricarboxylic acid PBTC; 2-Phosphonobutane -1,2,4-Tricarboxylic Acid (PBTCA)