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Determination of Acidity in Corn Sweetener Refining

Mineral Acidity: pH of 4.3 and below (Steps 1-5)
Total Acidity: initial pH to pH 8.3 (Steps 1-7)

  1. 58.3 ml or aliquot sample
  2. Place in 125 ml white evaporating dish
  3. Add two to three drops of methyl orange
  4. Stirring gently, titrate with .02N NaOH (sodium hydroxide) from red to orange yellow (pH 4.3)
  5. The calculation you should now perform is:
    Mineral acid (M.A.) gpg as CaCO3 = (ml titre X 58.3)/(ml of sample).
  6. To the above sample, add two to three drops of phenolphthalein and continue titration with .02N NaOH until sample becomes pink.
  7. The calculation you should now perform is:
    Total acid (T) gpg as CaCO3 = (ml titre X 58.3)/(ml of sample)

Note: This test is usually applied to the cation effluent water.