PBTCA has low content of phosphoric, has structural features ... , it is used as chelating agent and metal detergent. PBTCA is usually used together with zinc salt, copolymer, organophosphine, ... -1,2,4-Tricarboxylic Acid(PBTCA)SpecificationitemsindexAppearanceColorless or light yellow transparent liquidActive acid %50.0 minPhosphorous acid(as PO33-)0 ... minpH(1% solution)1.5~2.0 Solid PBTCA