再取一份: F AⅣ酸性,三乙醇胺Ca2pH125YCaY Ca2(掩蔽Fe3、AⅣF)Mg2+钙指示剂Mg(OH2测Ca Mg2+ (purplish red) (blue)3 再取一份： Fe3+ Al3+ 酸性，三乙醇胺 Ca2+ pH 12.5 Y  CaY Ca2+ （掩蔽Fe3+ 、Al3+）Mg2+ 钙指示剂 Mg(OH)2 测Ca Mg2+ (purplish red) (blue)