Simultaneous Determination Of U(Vi) and Pd (Ii) Using 4-Hydroxybenzaldehyde Thiosemicarbazone By Second Order Derivative Spectrophotometric Technique

The metals U(VI) and Pd (II) gives yellow coloration with the reagent 4-Hydroxy benzaldehyde thiosemicarbazone(4-HBTS) in acidic medium simultaneous determination of both the metal ions U(VI) and Pd (II) can be done by using second order derivative spectrophotometric technique. For the determination of composition of metal complexes Job’s method and mole ratio method were employed.


Introduction
Uranium is hexavalent and palladium is divalent transition metals. Uranium is a highly reactive metal, especially at elevated temperatures. Uranium is radioactive, and is the element for which the phenomenon of radioactivity was first discovered. Palladium is little harder than pure platinum and it is catalytically active in the colloidal state. Simultaneous determination of these two metal ions becomes difficult and poses many problems. A second order derivative spectrophotometric method is used for the simultaneous determination of two metal ions based on their reaction with 4-hydroxy benzaldehyde thiosemicarbazone (4HBTS).
Thiosemicarbazones have wide range of analytical applications in the determination of metal ions [1][2][3][4][5]. Thiosemicarbazones can be synthesized easily (Figure 1). Thiosemicarbazones forms stable complexes with different metal ions [6][7][8][9][10][11][12][13]. For getting improved resolution of spectral bands derivative spectrophotometry is chosen, for resolving two overlapped spectra and to eradicating matrix interferences in two component mixtures zero crossing method can employed [14,15]. Two simultaneous equations should be solved for the determination of components in a mixture in the absence of zero crossing point [16,17]. Without solving simultaneous equations, derivative spectrophotometric technique can be employed for analysis of two component mixtures [18,19]. The tolerance limit value of foreign increases using derivative spectrophotometric technique which intern decreases the interference of foreign ions. Resolution of spectral bands can be achieved using derivative spectrophotometry, which allows location and detection of wavelength of complex spectra which is poorly resolved and also decrease the effect of interferences of spectral background. Simultaneous determination of metal ions by derivative spectrophotometric technique is not much exploited [20][21][22].

Experimental Part
Shimadzu UV-Visible spectrophotometer (model UV-160A) used for the measurement of absorbance values and pH measurements were made by Elico digital pH meter (modelLI20).

Characterization
Perkin-Elmer 137 infrared spectrometer is used for IR spectrum of the compound in KBr. The assymmetric as well as symetric (-N-H) steching frequencis assigned to primary amino-group are noticed at 3458cm -1 and 3342cm -1 . frequency of aromatic proton (Ar-H) is observed at 3218 cm -1. The peak noticed at 1595cm -1 is ascribed to C=N stretching frequency of azomethine. The peak for -OH group is obeserved at 3028-3092 cm -1 . C=S stretching frequency is observed as strong peak at 1056cm -1 . The peaks for aromatic ring stretching frequency are observed in the range of 1530 -1 360cm -1 frequency. DRX 300 NMR spectrophotometer was used to record H-NMR spectrum. The charectarisation of phenolic -OH gives a peak noticed at δ-value 10.74 (1H). the peak for aromatic proton was observed at a peak attained at δ-value 7.86(4H) the peak recorded at δ-value 6.8 (2H) can be assigned to -NH 2 proton assigned to thionyl (C=S) group. the aldehydic proton gives a peak detected at δ-value 9.0. The -NH proton (Azomethine) given a peak at δ value 11.5.

Results and Discussion
The precursors, 1 ml of 1 x 10 -3 M uranyl acetate and 1 ml of 1      259

Simultaneous determination of U(VI) and Pd (II)
A

Tolerance effect
Tolerance limit of different metal ions associated with U(VI) and Pd(II) is investigated. Influence of several anions is also studied.
The appropriate data is presented in Table 1. An analysis of the data reveals that Cu (II), Ni (II), V(V) and Cr (VI) did interfere seriously in the determination of metal ions. Utmost of the anions does not interfere.

Application
The method developed by the author has been employed for the simultaneous determination of U(VI) & Pd (II) in simulated mixtures. The outcomes are presented in Table 2 and they are satisfactory.

Conclusion
The current work is simple, sensitive and highly selective for