硫氰酸根—吡罗红G显色体系的研究—分光光度法测定人尿中微量Zn和Mo

A STUDY OF COLOR SYSTEM OF THIOCYANATE AND PYRONINE G——SPECTROPHOTOMETRIC DETERMINATION OF MICROAMOUNT OF Mo AND Zn IN HUMAN URINE

用分光光度法在丙酮水溶液中,利用[MoO(SCN)_5]^(2-)和[Zn(SCN)_4]^(2-)络离子与吡罗红G(Pyronine简写PyG)发生的离子缔合反应,可以在不同酸度下,[H^+]=2.4mol.L^(-1)和PH=1.6分别测定钼和锌,本方法灵敏度高而不必事先分离. 在水溶液中,用连续变化法、斜率比及摩尔比法证明该离子缔合物的组成是PyG_2[Zn(SCN)_4]·2(PyG·SCN)和PyG_2[MoO(sCN)_5]·2(PyG·SCN),它们的摩尔吸光系数分别为ε_()576^(Mo)=1.05×10~5L/(mol.cm)和ε_(588)^(Zn)=7.19×10~4L/(mol.cm)·加入掩蔽剂此反应可直接测定人尿中锌和钼.

A highly sensitive spectrophotometric method has been developed for the determination of molybdenum and zinc based on the formation of ion-associate complex due to the [MoO(SCN)_5]^(2-) and [Zn (SEN)_4]^(2-)anionic complexes with pyronine G (PyG) in acetone-aqueous solution. By the change of the acidity, molybdenum(at [H^+]=2.4 mol·L^(-1)) and zinc (at pH=1.6) can be determined respectively and without preseparation. In the aqueous solution, the ion-associate complexes have the compositions of PyG_2 [MoO (SCN)_5]·2(PyG^+·SCN^-) and PyG_2 [Zn (SCN)_4]·2 (PyG^+·SCN^-)as established by the method of continuous variation, the slope ratio method and the Molar ratio method; the molar absorptivity of Mo(V)-SCN^--PyG complex is 1.05×10~5L·mol^(-1)·cm^(-1)at 576nm and that of ZN(11)-SCN^--PyG complex is 7.19×10~4L·mol^(-1)·cm^(-1) at 588nm. By addition of some masking agents, the reaction can be applied for direct determination of molybdenum and zinc in human urine.