Chromotropic acid

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Chromotropic acid
IUPAC name 4,5-dihydroxynaphthalene-2,7-disulfonic acid[1]
Identifiers
CAS number [148-25-4]
SMILES OS(=O)(=O)c1cc(O)c2cc(O)cc(c2c1)S(O)(=O)=O
Properties
Molecular formula C10H8O8S2
Molar mass 320.30 g/mol
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Chromotropic acid has the formula is (HO)2C10H4(SO3H)2.

It can be used for as a reagent in the quantitative determination of the systemic herbicide, 2,4-Dichlorophenoxyacetic acid.[2]

The usefulness of this reagent in quantitative determination is the formation of a red colouration (peaking at 580 nm wavelength) when chromotropic acid in 75% sulfuric acid reacts with formaldehyde. The colouration is specific to this aldehyde and is not produced from other organic species such as ketones and carboxylic acids.

[edit] References

  1. ^ Safety (MSDS) data
  2. ^ Plant Physiology Letourneau and Krog 27 (4): 822. (1952)