Paragraph 3 Reagents

All reagents shall be of analytical reagent (AR) grade, water for the preparation of reagents shall be distilled or de-ionised, and the reagents shall comprise the following solutions—

(a)

starch solution made up as follows—

(i)

an amount of soluble starch of known moisture content and of the appropriate grade for the determination of alpha-amylase, equivalent to 0.70 g of dry starch mixed to a thin cream with cold water; transferred to about 50 ml of boiling water, boiled for one minute and then cooled by immersion in cold water; three drops of toluene shall be added and the whole diluted with water to 100 ml in a volumetric flask; the solution shall not be retained for longer than 14 days;

(b)

solution of iodine made according to one of the following–

(i)

an accurately weighed amount of 0.1269 g of iodine and 3.6 g of potassium iodide dissolved in water such that the final volume of the solution is 1 litre; the volumetric flask containing the solution shall be protected from light and a fresh solution shall be prepared daily;

(ii)

the solution described in sub-paragraph (i) diluted from a stronger solution with appropriate adjustment of potassium iodide concentration; or

(c)

solution of trichloroacetic acid made up as follows—

(i)

15% (w/v) of trichloroacetic acid dissolved in water.