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PAN INDICATOR Print Download

C.A.S. No. 85-85-8
M.F. C15H11N3O
M.W. 249.27gm/mole


Solubility 0.1 %(0.1N EtOH) Clear solution
Absorption Maximum (in EtOH) ?max 462-466nm
Absorptivity (A1%/1cm in EtOH, at ?max) >670
Loss on drying (110°C) <5%
Suitability as metal indicator Passes test

Chemical name


InChI Key



Soluble in acetone, alcohol, and dilute aqueous alkali. Insoluble in water. 33.3 mg soluble in 1 mL of methanol

Product Description:

1-(2-Pyridylazo)-2-naphthol (PAN), an orange colored dye, is commonly used as an acid-base indicator. It can form chelates with metal ions, which makes it a valuable indicator in complexometric titrations. 1-(2-Pyridylazo)-2-naphthol is an indicator in complexometry and a reagent for the extraction and spectrophotometric determination of many transition metals.


The compound forms various colored metal chelates. The stability is greatly affected by the acidity. The alkali and alkaline earth metals do not form chelate with APN. The compound is used as an indicator in the complexometric titration of zinc, copper, cadmium, with EDTA. Amoung the metals reacting with the dye, most form reddish colored chelates.

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