Metal contaminants in commercial thiazine dyes.
The iron, potassium, sodium and zinc content of commercial samples of the thiazine dyes azure A (C.I. 52005), azure B (C.I. 52010), azure C (C.I. 52002), methylene blue (C.I. 52015), new methylene blue (C.I. 52030), polychrome methylene blue, thionine (C.I. 52000) and toluidine blue (C.I. 52040) have been determined by atomic absorption spectrophotometry. The metal concentration varied widely in the 38 samples examined--iron, potassium, sodium and zinc together comprised between 0.02% and 25.35% of individual samples.
D002852:Chromatography, Ion Exchange; D004340:Drug Contamination; D004880:Ergothioneine / Q000032:analysis; D007501:Iron / Q000032:analysis; D008670:Metals / Q000032:analysis* / Q000302:isolation & purification; D008751:Methylene Blue / Q000032:analysis; D011188:Potassium / Q000032:analysis; D012964:Sodium / Q000032:analysis; D013054:Spectrophotometry, Atomic; D013843:Thiazines / Q000032:analysis*; D015032:Zinc / Q000032:analysis
D008670:Metals; D013843:Thiazines; D012964:Sodium; D004880:Ergothioneine; D007501:Iron; D015032:Zinc; D011188:Potassium; D008751:Methylene Blue