biochemical indicator of the presence of carbohydrates in a solution; if carbohydrates are present a violet ring is formed by reaction with alpha-naphthol in the presence of sulfuric acid
indicador bioquímico da presenza de carbohidratos nunha solución; se os carbohidratos están presentes, fórmase un anel violeta pola reacción co alfa-naftol na presenza de ácido sulfúrico