10279. Xylenol Orange

Nomenclature

CAS number: 1611-35-4
N,N′-[(1,1-Dioxido-3H-2,1-benzoxathiol-3-ylidene)bis[(6-hydroxy-5-methyl-3,1-phenylene)methylene]]bis[N-(carboxymethyl)glycine]; 3-3′-bis[N,N-bis(carboxymethyl)aminomethyl]-o-cresolsulfonephthalein.
C31H32N2O13S; mol wt 672.66.
C 55.35%, H 4.80%, N 4.16%, O 30.92%, S 4.77%.

Description and references

Cation chelant; sulfonephthalein titration indicator that forms soluble, colored complexes with metal ions. Exists in multiple sodium salt forms. Prepn from cresol red, q.v.: J. Krbl, R. Pribil, Chem. Ind. (London) 1957, 233; and chromatography: M. Murakami et al., Talanta 14, 1293 (1967) DOI; H. Nakayama et al., Anal. Sci. 5, 619 (1989) DOI. Polarography studies: M. Véber, L. J. Csányi, J. Electroanal. Chem. 101, 419 (1979) DOI. Ionization constant determn: M. B. Gholivand et al., Talanta 46, 875 (1998) DOI. Spectroscopy studies: S. Kiciak, H. Gontarz, ibid. 33, 341 (1986) DOI. Metal chelate studies: K. Ogura et al., J. Inorg. Nucl. Chem. 43, 1243 (1981) DOI. Hydroperoxide assay studies: C. Gay et al., Anal. Biochem. 273, 149 (1999) DOI PubMed; C. A. Gay, J. M. Gebicki, ibid. 315, 29 (2003) DOI PubMed; K. Arab, J.-P. Steghens, ibid. 325, 158 (2004) DOI PubMed. Use in fluorometric detection of calcified tissue: B. A. Rahn, S. M. Perren, Stain Technol. 46, 125 (1971) PubMed; Y.-H. Wang et al., Biotechnol. Prog. 22, 1697 (2006) PubMed; in fluorine determn: J. A. Ruzicka, et al., Talanta 13, 1341 (1966) DOI; in DNA determn: X. Chen et al., Spectrochim. Acta A 61, 2215 (2005) DOI PubMed. Reviews of analytical uses: B. Budesinsky in Chelates in Analytical Chemistry, H. A. Flaschka, A. J. Barnard, Jr., Eds. (Marcel Dekker, Inc., 1967) pp 15-47; S. Rani et al., Chem. Era 13, 372-388 (1978).

Chemical structure

Properties

Dark solid. pKa1 1.74; pKa2 1.09; pKa3 0.76; pKa4 1.15; pKa5 2.58; pKa6 3.23; pKa7 6.40; pKa8 10.46; pKa9 12.58. Color of aq soln transitions from yellow to red between pH 6.4 and 10.4; color is dependent upon protonation state.

Derivative

Tetrasodium salt.

Nomenclature

CAS number: 3618-43-7
C31H28N2Na4O13S; mol wt 760.58.
C 48.95%, H 3.71%, N 3.68%, Na 12.09%, O 27.35%, S 4.22%.

Properties

Dark solid. Absorption max (0.1 N sodium hydroxide): 580 nm. Excitation max: 440 nm; 570 nm. Emission max: 610 nm. Freely sol in water; very slightly sol in ethanol.

Use

Chromogenic indicator for complexometric and spectrophotometric determn of numerous metal ions (restricted to pH range 0.0 to 6.0). Stain to demonstrate calcification in biological tissue. In the detection of fluorine, hydroperoxides, and DNA.