Orcinol may be obtained from some species of lichens such as Lecanora tinctoria and Rocella tinctoria for use in the production of the natural dye, orcein, and for use as a reagent in chemical tests such as Bial's orcinol test.
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... acid. I would guess there’s HPLC and/or spectrophotometric/colorimetric assays. Keto-glutarate, for example, is (if I remember correctly) an orcinol-positive sugar, but then so are many sugars so if it needs to be specific, there has to be some sort of separation before quantitation.
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