Spectrophotometric determination of micro palladium with chlorophenolazo rhodanine in microemulsion medium

The color reaction of the reagent chlorophenolazo rhodanine with Pd (Ⅱ) was studied in the presence of microemulsion consisting of CTMAB,n-C4H9 OH,C7H14,H2O.A new spectrophotometry for the determination of trace Pd(Ⅱ)has been proposed.Results show that the new color reagent reacts with Pd(Ⅱ) to form a stable red complex(1∶2)in the medium of HAc-NaAc buffer solution at pH 5.3.The maximum absorption wavelength and apparent molar absorptivity are 500 nm and 1.79×105 L·mol-1·cm-1,respectively.Beer's law is obeyed in the range of 0.01～12 μg for Pd(Ⅱ) in 10 mL of color solution.The detection limit is 0.000 3 μg/mL.The method has been applied to the determination of trace Pd (Ⅱ) in palladium catalyst and molecular sieve with the RSDs of 1.17%-2.34%(n=6)and recoveries of 98.1%-98.6%.