Cards (5)

    • Test for starch
      Add iodine (potassium iodide solution) to the sample. If the solution goes from brown-orange to blue black starch is present.
    • Test for lipids
      The emulsion test - add ethanol to the sample and shake the test tube then add water to it. Lipids are present if a white emulsion appears.
    • Test for reducing sugars
      The Benedict's test - add Benedict's reagent to the sample then heat the solution gently. A brick-red precipitate indicates that reducing sugars are present.
    • Test for non-reducing sugars
      The Benedict's test (for non-reducing sugars) - add hydrochloric acid to the sample and heat gently, then neutralise the sample with sodium hydrogencarbonate solution. Add Benedict's reagent to the sample. It's positive if there's a brick-red precipitate.
    • Test for proteins
      Biuret test - add sodium hydroxide solution to the sample. Add copper sulphate solution. If proteins are present the solution will turn purple, if not it will stay blue.