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Appearance
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Dark red to maroon to violet or purple powder or crystals
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Identity
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Passes test
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pH transition range (4.2 - 6.2)
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Pink Red – yellow orange
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Insoluble matter in ethanol (1 g/L)
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Passes test
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Absorption maxima (buffer pH 4.2)
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523 - 526 nm
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Absorption maxima (buffer pH 6.2)
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427 - 437 nm
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Loss on drying (at 110°C)
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Max 5.0%
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Residue on ignition (as SO4)
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Max 2.0%
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