SPECTROPHOTOMETRIC DETERMINATION OF TRACES OF PALLADIUM BASED ON ITS INHIBITORY EFFECT ON THE ADDITION REACTION BETWEEN SULFITE ION AND METHYL GREEN

A simple and sensitive kinetic method for the determination of traces of palladium (40-280 ng/ml) based on its inhibitory effect on the addition reaction between methyl green and sulfite ion is proposed. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of methyl green at 630 nm using the fixed time method. The limit of detection is 15 ng/ml and the relative standard deviation for 100 ng/ml Pd^2+ is 1%. The interfering effect of various ions was studied. The method was applied to the determination of palladium in a sample of activated charcoal.