Extractive Spectrophotometric determination of palladium with 3-Hydroxy-2-(2'-thienyl)- 4H-chromen-4-one in alkaline medium

A rapid, simple, selective and sensitive method for the determination of palladium in trace amounts has been developed, which is based on the reaction of 3-Hydroxy-2-(2’-thienyl)-4H-chromen-4-one with the metal ion in alkaline medium(pH 8.5-9.2). The yellow colored palladium complex formed is quantitatively extracted into chloroform, whose absorbance is measured at 455nm. A large number of cations do not interfere; whereas , amongst anions/complexing agents , only nitrite ,thiourea and Ascorbic acid show interference. It obeys Beer’s law in the range 0.01-0.1 µg. PdmL -1 . The molar absorptivity and Sandell’s sensitivity of the system are 3.301x10 4 Lmol -1 cm -1 and 0.0032µgPdcm -1 respectively. The ratio of metal to ligand in the extracted complex is determined as 1:1.The validity of the method is tested by carrying out analysis of various samples with satisfactory results.