USP is updating the General Chapter <591> «Zinc Determination» monograph to include ion chromatography as a method for the assay. Zinc oxide is used in various skin care creams, drugs, and drug products. The ion chromatography analysis involves separation of zinc using, e.g., L91 (Metrosep A Supp 10) followed by post-column reaction using 4-(2-pyridylazo)resorcinol (PAR) reagent and subsequent detection at 530 nm wavelength.

Keywords: USP<591>



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