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Appearance
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Dark blue, crystalline powder with a copper-coloured sheen, or green crystals with a bronze-coloured sheen
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Dye content
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Min 82%
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Absorption maxima in 50% ethanol
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660 - 665 nm
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Specific absorptivity A1%/1 cm (λmax; 0.003 g/L; ethanol)
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2250-2750
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Loss on drying (at 105°C)
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8.0 - 22.0%
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