BS 4427-3:1989(2011)
工业用三聚磷酸钠(三磷酸五钠)和焦磷酸钠(焦磷酸四钠)试验方法 第3部分:工业用缩合磷酸盐(包括食品):铁含量的测定
Methods of test for Sodium tripolyphosphate (pentasodium triphosphate) and sodium pyrophosphate (tetrasodium pyrophosphate) for industrial use — Part 3 : Condensed phosphates for industrial use (including foodstuffs): determination of iron content