Abstract
Silver is quantitatively extracted by shaking with thiothenoyltrifluoroacetone (STTA) solution in carbon tetrachloride from an aqueous solution containing pyridine at pH 6.8±0.1. The silver complex extracted is stable and has an absorption maximum at around 420 nm against a reagent blank. Beer's law holds over the range of 2.5-35 μg of silver/10 ml of organic phase. The molar absorptivity is 5800. The sensitivity is 0.019 μg Ag/cm2 for an absorbance of 0.001. The coefficient of variation in precision is 1.9% for 30 μg of silver. The effect of various kinds of co-existing ions was examined. Copper, cobalt, lead, zinc, nickel, mercury, manganese, cadmium, aluminum, iron, gold, sulfide, and cyanide interfere in the determination but the permissible amount of these interfering ions except gold, mercury, sulfide, and cyanide can be increased by adding EDTA solution as a masking agent.
