2. Materials and methods
2.1. Materials
Hydrochloric acid, soluble starch and sodium hydroxide from.
Merck (Chennai) were used as received. Glacial acetic acid was
purchased from Qualigens (Chennai). Zinc nitrate hexahydrate was
obtained from Hi-Tech Enterprises Private Limited (Chennai). Crab
shells and neem oil were purchased from import and export compa-.
nies (Chennai) and from Cyrus Enterprises (Chennai), respectively.