铝镁合金中镁的测定一般都采用络合滴定法。所用试剂有铬黑T、PAN-Cu等。用铬黑T时须加三乙醇胺、氰化钾掩蔽A1~(+++)、Fe~(+++)、Cu~(++)、Mu~(+++)、Ni~(++)等。用PAN-Cu时加酒石酸掩蔽Fe~(+++)、Al~(+++),在pH6用EDTA络合除镁以外之干扰元素,而后调到pH10测镁。铬黑T虽为测镁较灵敏之指示剂,但要用剧毒氰化钾试剂。PAN-Cu虽不用氰化钾,但要两次滴定,且酒精消耗量较大。 Determination of magnesium in aluminum magnesium alloy are generally used complexation titration. The reagents used are chrome black T, PAN-Cu and so on. When adding triethanolamine and potassium cyanide, the masking of A1 ~ (+++), Fe ~ (+++), Cu ~ (++), Mu ~ (+++), Ni ~ (++ )Wait. Tartaric acid masked Fe ~ (+++), Al ~ (+++) with PAN-Cu, complexed with EDTA at pH 6, and then adjusted to pH10 to measure magnesium. Although chromium black T is more sensitive indicator of magnesium, but to use highly toxic potassium cyanide reagent. Although PAN-Cu does not use potassium cyanide, it should be titrated twice and alcohol consumption is larger.