2,6-Dichloroindophenol sodium can be used for the determination of ascorbic acid, and redox indicator and chromatographic analysis reagent.
Dissolve it in 0.001M phosphate buffer, pH 7.5 (alternatively, about 2g of the dye is dissolved in 80mL of M HCl), and extracted into diethyl ether. The extract is washed with water, extracted with aqueous 2% NaHCO3, and the sodium salt of the dye is precipitated by adding NaCl (30g/100mL of NaHCO3 solution), then filtered off, washed with dilute NaCl solution and dried. It has max at 605nm. [Hiromi et al. Anal Biochem 101 421 1980.] The acetate M 310.1 has m 101-103o (from Et2O/pet ether) and 99.5-100.5o (from Et2O). [Beilstein 13 IV 1078-1079.]
