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The use of chemicals and waste generation from laboratory is one way to cause environmental pollution. As a result, the research in analytical chemistry is concerns to make laboratory practices to be more environmentally friendly, such as reduction or elimination of the use of hazardous chemicals, which are toxic to the environment. This work applied the flow injection analysis using roselle (Hibiscus sabdariffa L.) extract as a natural reagent for determination of sulfite. This method reduced the use of synthetic reagent. The dried roselle extract was prepared in acetate buffer (pH 3) and the red color was obtained. When reacted with sulfite, the color of the extract was decreased. The decreasing of color intensity could be measured by a laboratory made colorimeter. The calibration graph obtained was linear over the range of 5-100 mg/L. The method can be applied to determine the sulfite content in beverages samples.
Keywords: sulfite; flow injection; natural reagent
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