三溴偶氮氯膦比色测定1AW中的总稀土

TRIBROMO-CHLOROPHOSPHONAZO USED FOR PHOTOSPECTROMETRIC DETERMINATION OF TOTAL RARE EARTH IN HIGH-LEVEL LIQUID WASTE

一、引言三溴偶氮氯膦(CPA-tB)是氯膦偶氮的衍生物,引入“三溴”为的是引起变色酸双偶氮化合物的不对称性,调整分子的截面积,改善分子共轭体系的状态,使反应的灵敏度与选择性有所提高。它是由武汉大学合成的,同时已直接用它来比色测定土壤中的总稀土。在此,为测定高放废液中的总稀土,也选用这一试剂。

The Procedure determining the cocentrations of total rare earth and their determination photospectrometrically with a new reagent, tribromochlorophosphonazo (CPA-tB), that is 7-[1-(2,4,6-tribromo-phenyl) azo]-2-[1-(2-phosphono-4-chloro-phenyl) azo]-chromotropic acid, in high-level liquid waste and some charactors of CPA-tB are studied. CPA-tB and its complexes of rare earth elements are stable in the glycol-H_2O system. Adding glycol shifts the absorption spectrum to left and increases the molar extinction coefficient. The molar extinction coefficients are respectively 7.16×10~4(Y), 11.9×10~4(La),11.7×10~4(Ce,Pr),11.9×10~4(Nd), 11. 6×10~4(Sm,Eu), 11.4×10~4(Gd) and 11.4×10~4 (RE) in the glycoI-H_2C_2O_4-H_3PO_4-H_2O system at 643 nm. Th interferes severely the determination of total rare earth, and other elements, U(<100μg), Al(<20μg),Fe(<400μg),Ni,Zr(<100μg respectively) and some anions, MoO_4^(2-)(<2800μg), EDTA(<20mg), F-(<266μg), Cl-(<110 mg), NO_3-(<150mg) do not interfere it.