关键词: 对甲基二溴偶氮胂, 稀土, 测定小麦, 铝合金

Abstract: Anew reagent,p-methyldjbronioarsenazo, was synthesized and a simple, rapid, seusitive and selective method for the spectro-protometric determination of rare earths was developed based upon the formation of p-methyldibromoarse-nazo-rare earth complexes.In HCl-NaAc medium, the reaction of rare earths with p-methyldibromoar-senazo forms blue violet complexes, which are stable over 24 hours. The absor-bance was measured at 635nm. The apparent molar absorptivity coefficient of rare earth complexes are very much the same (ε_La= 1.38×10⁵, ε_Yb = 1.01 ×10⁵, ε_Y= 1.17×10⁵). The composition of complex is La(Y):R= 1:2.The method has been successfully applied to the determination of micro amount of rare earths in wheat and aluminium alloy.

Key words: P-methyldibromoarsenazo, Rare earth, Determination wheat, Aluminium alloy