10273. SPADNS

Nomenclature

CAS number: 23647-14-5
4,5-Dihydroxy-3-[2-(4-sulfophenyl)diazenyl]-2,7-naphthalenedisulfonic acid sodium salt (1:3); 4,5-dihydroxy-3-[(4-sulfophenyl)azo]-2,7-naphthalenedisulfonic acid trisodium salt; 2-(4-sulfophenylazo)-1,8-dihydroxy-3,6-napthalenedisulfonic acid trisodium salt; trisodium 2-(p-sulfophenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonate.
C16H9N2Na3O11S3; mol wt 570.41.
C 33.69%, H 1.59%, N 4.91%, Na 12.09%, O 30.85%, S 16.86%.

Description and references

Cation chelant; dye ligand that reacts with metal ions to form colored complexes. Prepn from chromotropic and sulfanilic acids, q.q.v.: G. Banerjee, Fresenius Z. Anal. Chem. 146, 417 (1955) DOI. Metal chelate studies: idem, ibid. 147, 105 (1955) DOI; idem, ibid. 148, 349 (1955) DOI; idem, Anal. Chim. Acta 16, 56, 62 (1957) DOI; A. K. Bhattacharjee, M. K. Mahanti, Indian J. Chem. 20A, 427 (1981); M. S. Rizk et al., Egypt. J. Chem. 36, 199 (1993); and antifungal activity: G. Pandey, K. K. Narang, Bioinorg. Chem. Appl. 3, 217 (2005) DOI. Fluorine determn: G. Banerjee, Anal. Chim. Acta 13, 409 (1955) DOI; R. P. Hollingworth, Anal. Chem. 29, 1130 (1957) DOI; E. Bellack, P. J. Schouboe, ibid. 30, 2032 (1958) DOI; L. C. Peck, V. C. Smith, Talanta 11, 1343 (1964) DOI. Infrared and Raman spectroscopy studies: G. G. Siu, Z. L. Chen, J. Raman Spectrosc. 24, 173 (1993) DOI.

Chemical structure

Properties

Red powder. Irritant. Aq soln is scarlet, pH 6.9, pKa ~ 9. Absorption max (pH 5.3-6.9): 512 nm. Sol in water; slightly sol in ethanol.

Use

Chromogenic indicator for spectrophotometric determn of metal ions including beryllium, thorium, zirconium, cobalt, nickel, iron, aluminum, magnesium, calcium, and rare earth metals. Also in determn of fluoride ion, especially in biological samples.