The starch content in paper is determined using the RH 23/09 method developed by PTS. In this method, shredded paper pieces (about 2 g) are transferred to a fiber slurry with distilled water. The fiber slurry is adjusted to the pH range effective for the enzyme amyloglucosidase by means of diluted acetic acid and acetate buffer. The starch contained in the fiber slurry is hydrolyzed to glucose by addition of the enzyme and tempering.

Afterwards the glucose content is determined quantitatively by means of a biosensor and converted into the starch content. When determining the starch content of native starch, 100% recovery is assumed. Depending on the degree of modification of the starch, the recovery is reduced. The starch content is given in [mg starch/g fiber] or in [%]. The detection limit of this method is 2 mg/g.