An optimum pH for the demonstration of chitin in Periplanata americana using Lugol's iodine.

Modification of chitosan test of Campbell is suggested with a controlled procedure involving heating with saturated potassium hydroxide at 160 degrees C for a period of 45 min and subsequent washing of the deacetylated chitin in running water and application of Lugol's iodine solution (1:2:300, w/w/v) at a pH range of 1.4 to 4.0, thus replacing the use of dilute sulphuric acid. Consistent results were obtained not only with the cuticle of Periplanata americana but also with the cuticle of Emerita asiatica (crustacea).