微量铽的萤光光度测定——铽与吡啶-2,6-二羧酸螯合物的萤光

铽与吡啶-2,6-二羧酸(以下简称DPA)形成螯合物的萤光有人从生物化学角度作过一些研究^1],但对测定稀土氧化物中微量铽的研究未见报导。本文系统地研究了Tb³⁺-DPA螯合物萤光产生的条件,拟订了测定稀土氧化物中微量铽的萤光光度法,探讨了螯合物萤光强度与其组成的关系。

SPECTROFLUORIMETRIC DETERMINATION OF MICROAMOUNTS OF TERBIUM-FLUORESCENCE OF CHELATE OF TERBIUM WITH DIPICOLINIC ACID

The chelate compound formed by terbium with dipic clinic acid (DPA) has been used as the basis for a selective spectrofluorimetric determination of microamounts of terbium. At pH5-12, DPA]/Tb]≥10, the chelate of terbium with DPA forms quickly. The composition of the chelate is Tb:DPA=l:3. The system absorbs the radiation characteristic of DPA at 280nm, and emits the band fluorescence of the dipicolinate of terbium with the emission characteristic of terbium at 542nm.A linear increase in 542nm emission intensity was obtained in solution containing 4-40ng/ml and 0.02-0.24/μg/ml of terbium. The interference of other metals was examined. When sufficient DPA was present to chelate the terbium, the remaining lanthanides and Ca, Mg, Cu, Zn, Al did not affect the fluorescence intensities. The interference of ferric ion can be masked by EDTA. Satisfactory results were obtained by the proposed method for the determination of terbium in LaOBr and La₂O₃ Samples.