Synthesis of 5,6-Diphenyl-2,3-dihydro-1,2,4-triazine-3-thione as a New Reagent for Spectrophotometric Determination of Palladium

A new chromogenic reagent for the sensitive and selective determination of Pd ions in aqueous solution was synthesized. The reagent, 5,6-diphenyl-2,3-dihydro-1,2,4-triazine-3-thione, forms colored complexes with a few heavy metal ions. A 1:1 (M:L) yellowish orange colored complex of DPhDTT-Pd was formed in methanol. The molar absorptivity is 6.67×10 L mol cm. Bee’s law was obeyed in the concentration range of 10-50 μg/mL at λmax 385 nm. The accuracy and precision of the method were evaluated on within-day and between-day basis; the relative error was ≤ 3.13 and the relative standard deviation was ≤3.96. The method was successfully applied to the synthetic samples and results compared with atomic absorption method. There was no significant difference between two methods (p>0.05).