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3, 4-Dihydroxybenzaldehydeisonicotinoylhydrazone was prepared, characterized with spectral analyses and used for developing a new method for the simple, sensitive and rapid spectrophotometric determination of vanadium(V) which gives maximum absorbance at wave length 360 nm. The metal ion gives a yellow colored complex with 3, 4-DHBINH in acetate buffer of pH 5.5 with 1:1 (metal:ligand) composition. The method obeys Beer's law in the range 0.5-5.3 microg mL(-1) of vanadium(V). The molar absorptivity and Sandell's sensitivity were found to be 1.29 x 10(4) L mol(-1) cm(-1) and 0.003949 microg cm(-2) respectively. The correlation co-efficient of the V(V)-3, 4-DHBINH complex was 0.992 which indicated an excellent linearity between the two variables. The repeatability of the method was checked by finding the relative standard deviation (RSD) as 0.424% (n = 5), and its detection limit 0.01677 microg mL(-1) of vanadium(V). The instability constant of the method was calculated by Asmus' method as 4.1666 x 10(-3). The interfering effect of various cations and anions were also studied. The proposed method was successfully applied to the determination of vanadium(V) in environmental samples (water and soil) tobacco leaves and alloy samples. The validity of the method was tested by comparing the results with those obtained using an atomic absorption spectrophotometer.

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A new reagent, benzyloxybenzaldehydethiosemicarbazone (BBTSC) was synthesized and a new method was developed for the simple, highly selective and extractive spectrophotometric determination of palladium(II) with BBTSC at wave length 365 nm. The metal ion formed a yellow colored complex with BBTSC in acetate buffer of pH 5.0, which was easily extractable into cyclohexanol with 1:1 (Metal: Ligand) composition. The method obeys Beer's law in the range of 5-60 ppm. The molar absorptivity and Sandell's sensitivity were found to be 0.4´10 4 Lt. mol -1 cm -1 and 0.02661 mg cm -2 , respectively. The correlation co-efficient of the Pd(II)-BBTSC complex was 0.9657, which indicated an excellent linearity between the two variables. The repeatability of the method was checked by finding the relative standard deviation (RSD) (n = 10), which was 0.321% and its detection limit 0.016875 mg.mL -1 . The instability constant of the method was calculated by Asmus' method as 3.5714´10 -4 . The interfering effect of various cations and anions were also studied. The proposed method was successfully applied for the determination of palladium(II) in synthetic and water samples. The results were compared with those obtained using an atomic absorption spectrophotometer, testing the validity of the method.Keywords: Palladium(II); Benzyloxybenzaldehydethiosemicarbazone (BBTSC); Sensitive extractive spectrophotometry; Environmental and synthetic samples. INTRODUCTIONPalladium and its alloys have a wide range of applications, both in the chemical industry and in instrument making. It also has widespread use in dental and medical devices and the manufacture of jewelery.1,2 Due to its wide applications, the need arose for the development of simple and rapid methods for the quantitative determination of palladium(II). For the determination of palladium at micro levels, several analytical techniques such as AAS, ICP-AES, ICP-MS, X-Ray fluoroscence spectroscopy and spectrophotometer are employed. Among these, spectrophotometric methods are preferred because they are cheaper and easy to handle. Many carbonyl derivatives are used for spectrophotometric as well as extractive spectrophotometric determination of metal ions. Among these reagents, thiosemicarbazones play a unique role. The metal chelates of these sulfur and nitrogen containing organic reagents find a wide range of applications in medicine and agriculture.3 A thorough literary survey has revealed that many thiosemicarbazones are available for the extractive spectrophotometric determination of palladium(II). [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] However, some of these existing methods are less sensitive and have poor selectivity for the determination of palladium(II). In the present paper, a new reagent, benzyloxybenzaldehydethiosemicarbazone (BBTSC) is synthesized and used as a complexing agent for the development of a selective, rapid and sensitive extractive spectrophotometric determination of palladium(II) in water samples and synthetic mixtures. This developed method is...