Ammonium oxalate

We purchased Bi (NO₃)₃·5H₂O, Na₂WO₄·2H₂O, Fe (NO₃)₃·9H₂O, cetyltrimethylammonium bromide (CTAB), terephthalic acid, ethylene glycol(C₂H₅OH), ammonium oxalate, isopropanol, sodium sulfate (Na₂SO₄), terephthalic acid, 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and hydrogen peroxide solution from Sino Pharm Chemical Reagent Co., Ltd. (China). All chemicals were used without further purification.

The ripe apples (Red Fuji) and tomatoes (Iseaei tomato) produced in Shandong province of China were used in this work, which were purchased from the supermarket. Ethanol, acetone, citric acid, oxalic acid, ammonium oxalate, dimethyl sulfoxide (DMSO), Carbazole (C₁₂H₉N), sodium nitrate (NaNO₃), acetic anhydride ((CH₃CO)₂O) and sodium azide were of analytical grade, while mEthanol and chloroform were of high-phase liquid chromatography grade (Sinopharm Chemical Reagent Co., Ltd., Beijing, China). All the chemicals were purchased from Shen Test Chemical Co., Ltd. (Wuhan, China). The sugar standards including Glc, fucose (Fuc), Ara, Xyl, Gal, GalA, Rha, and mannose (Man) were purchased from Sinopharm Chemical Reagent Co., Ltd. (Beijing, China). Methyl iodide (CH₃I) was purchased from Energy Chemical Reagent Co., Ltd. (Shanghai, China). Sodium borodeuteride (NaBD₄), N-(3-Dimethylamino-propyl)-N′-ethyl-carbodiimide hydrochloride (EDC), and trifluoroacetic acid (TFA) were purchased from Sigma-Aldrich Co. Ltd. (St. Louis, Missouri, USA). 1-Phenyl-3-methyl-5-pyrazolone (PMP) was purchased from Aladdin Co., Ltd. (Shanghai, China).