Ferric chloride fecl3

The reagents were purchased from commercial sources and were used without further purification. Ferric chloride (FeCl₃) was purchased from Macklin (Shanghai, China). Cysteine and 3,3′,5,5′-tetramethylbenzidine (TMB) were purchased from Sigma-Aldrich (Shanghai, China). Chitosan (CS) and Glucose oxidase (Gox) were purchased from Sangon Biotech (Shanghai, China). DNS Reducing Sugar Detection Kits were purchased from Solarbio (Beijing, China).

Four-year-old roots of P. ginseng were collected from Changbai Mountain district, Jilin, China, and were authenticated by Prof. Guangshu Wang, School of Pharmaceutical Sciences, Jilin University, Changchun, China.
Distilled water was purchased from Hangzhou Wahaha Group Co., Ltd. (Hangzhou, China); 1, phenanthroline, ferrous sulfate (FeSO₄), potassium ferricyanide, trichloroacetic acid, ferric chloride (FeCl₃), ferrozine, vitamin C (VC), and ethylene diamine tetraacetic acid (EDTA) were from Macklin Biochemical Co., Ltd. (Shanghai, China); trifluoroacetic acid (TFA), hydroxylamine hydrochloride, pyridine, acetic anhydride, chloroform, n-butanol, and ethanol were from Sigma Aldrich Chemical Co., Ltd. (St. Louis, MO, USA); DEAE (diethyl amino ethyl) cellulose was from Yuanye Bio-Technology Co., Ltd. (Shanghai, China); Standard sugars including mannose, ribose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, and arabinose were from Sino-pharm Chemical Reagent Co., Ltd. (Shanghai, China); T-series Dextran standards including T-10, T-40, T-70, T-100, and T-500 kDa were from the National Institutes of Food and Drug Control (Beijing, China). All of the reagents used in this study were of the highest quality available from commercial vendors and were of analytical grade.