稀土硅鎂合金中稀土總量的測定——偶氮胂Ⅲ分光光度法

Spectrophotometric Determination of Total Amount of Rare Earth Elements in the Ferroalloy of Containing Rare Earth Silicon and Magnesium with Arsenazo-Ⅲ

摘要: 在水-乙醇介質中,稀土與偶氮胂Ⅲ在pH為1.2~2.1的酸度范圍內可形成1:2的紫紅色絡合物,摩爾吸光系數高達8.2×10⁴l·mol·cm^-1,含稀土總量為0~50μg/25ml范圍內服從比爾定律。鐵的干擾采用EDTA掩蔽,避免了復雜的分離手續。該方法具有較高的靈敏度,選擇性、重現性良好,用于稀土硅鎂合金中稀土總量的測定,分析結果滿意,已用于生產。

Abstract: A rapid sensitive and selective spectrophotometric method for the determination of total amount of the rare earth elements in the ferroalloy of containing rare earth silicon and magnesium has been developed. A purplish red complex which has ratio of RE to Arsenazo-Ⅲ to be 1:2 can be formed in the range of pH 1.2~2.1 in the ethanol aqueous solution (λ_max=648nm,λ₆₄₈=8.2×10⁴ mol^-1cm^-1). Beer's law is obeyed in the concentration range of 0 to 50μg/25ml.The interference of Fe(Ⅲ) can be covered with EDTA.