Identification, separation by spiral high-speed counter-current chromatography, and quantification of 7-chloro-5-methyl-2H-1,4-benzothiazin-3(4H)-one, an impurity in the thioindigoid color additive DC Red No. 30 and its lakes
| Autor: | Jackson F. Wood, Clark D. Ridge, Yoichiro Ito, Marianita Perez-Gonzalez, Adrian Weisz |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Thiazines
Color 010402 general chemistry 01 natural sciences Biochemistry High-performance liquid chromatography Analytical Chemistry chemistry.chemical_compound Countercurrent chromatography Impurity Coloring Agents Countercurrent Distribution Spiral Chromatography High Pressure Liquid Solvent system Chromatography Ethanol Color additive 010401 analytical chemistry Organic Chemistry Water General Medicine Contamination 0104 chemical sciences chemistry Solvents Hydrophobic and Hydrophilic Interactions |
| Zdroj: | Journal of chromatography. A. 1637 |
| ISSN: | 1873-3778 |
| Popis: | An impurity in the color additives D&C Red No. 30 (R30) and D&C Red No. 30 lakes (R30L) was newly identified and characterized as 7-chloro-5-methyl-2H-1,4-benzothiazin-3(4H)-one (BTZ), and its extent and level in certified batches of these color additives was determined. BTZ was extracted from the dye with ethanol, resulting in a crude extract enriched to a concentration of over 60%. BTZ was then separated from a portion of the enriched extract by high-speed counter-current chromatography using a spiral-tube assembly column with intermittently pressed tubing of 60 ml capacity. It was the first reported use of such a column to separate a small, moderately hydrophobic compound. The two-phase solvent system was also moderately hydrophobic, consisting of hexane-ethyl acetate-methanol-water (5:2:5:2), and the retention of the organic stationary phase measured after the separation was 83.3%. The separation yielded BTZ of two purity grades, the higher of which (~95.5%) was used as a standard to quantify the impurity in 37 batches of R30 and R30L using an HPLC method developed and validated for that purpose. Analyses revealed a wide range of BTZ levels across batches |
| Databáze: | OpenAIRE |
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