Whats the principle of the in-line total recoverable phenolics?
The sample is fed into a continuously flowing carrier stream, mixed with phosphoric acid and distilled in-line. The distillate, containing steam volatile phenolic compounds, is then mixed with continuously flowing solutions of 4-aminoantipyrine and potassium ferricyanide. Phenolic compounds in the distillate are oxidized by ferricyanide, and resulting quinones react with 4-aminoantipyrine forming yellow condensation products, which are determined by colorimetric detection at 500 nm.
