Methanol

GFs of various ages were collected in June 2019 from Fusong (Jilin) and authenticated by Professor Changbao Chen (Changchun University of Chinese Medicine). After steaming at 40°C for 48 h, then crushed through 20-mesh sieves.
Ginsenoside Re (purity >98%) was obtained from the Department of Organic Chemistry, Jilin University; bovine serum albumin (BSA) was purchased from the Chinese Academy of Metrology; the glucose standard was purchased from Beijing Putian Tongchuang Biotechnology Co., Ltd. (Beijing, China); n-alkanes (C₈-C₃₀) was purchased from Alfa Aesar (Tewksbury, MA, USA); methanol, anhydrous ethanol, concentrated sulfuric acid, and glacial acetic acid (all analytically pure) were purchased from Beijing Chemical Plant (Beijing, China); polydimethylsiloxane-divinylbenzene solid-phase microextraction head (PDMS-DVB 65 μm) and 12 mL headspace vials were purchased from Supelco (Bellefonte, PA, USA).

ZnONPs were obtained from the Technical Institute of Physics and Chemistry, CAS (Beijing, China). Zinc salt (0.015 M, Aldrich) and 0.1 g of dimethyl sulfone (Aldrich) were first dissolved in 80 mL methanol (Beijing Chemical Works) with continuous stirring at 60 °C. Subsequently, 40 mL of 0.001 M KOH (Aldrich) was added at a rate of 1 mL per minute, and the reaction was kept at 60 °C for 12 h to obtain 10 nm ZnONPs. The precipitate was washed three times with ethanol to remove soluble impurities, dried at 65 °C for 12 h, and stored at room temperature before use.

Interventionary white mineral oil (WO) and oleic acid (OA), all of industrial grade were purchased from Jingkai Chemical Factory of Renqiu, Ltd. (Cangzhou, China). Concentrated sulfuric acid, sodium hydroxide, and sulfamic acid are all analytical purities and purchased from Guangdong Thorn Water Technology Co., Ltd. (Guangdong, China). Other reagents include methanol (MT), ethylene glycol (EG), and sodium carbonate anhydrous, which are of analytical purity and were purchased from Beijing Chemical Factory.

Chloroauric acid tetrahydrate (HAuCl₄∙4H₂O) was purchased from Shenyang Jinke Reagent Co., LTD (Shenyang, China). The pure product of clenbuterol hydrochloride (C₁₂H₁₈Cl₂N₂O·HCl, 98.8%) was received from Beijing Shengda-Huijie Technology Co., LTD (Beijing, China). Sodium citrate (C₆H₅Na₃O₇) and sodium chloride were obtained from Shanghai Macklin Technology Co., LTD (Shanghai, China). Ethyl acetate (C₄H₈O₂), acetone, methanol, and acetonitrile were purchased from Beijing Chemical Plant. All reagents were dissolved and diluted with ultrapure water. The fresh pig muscle tissues were bought at Beijing Xing-fu Supermarket. All glassware was cleaned with aqua regia before the test.

Petroleum ether, methanol, and phosphoric acid were analytical pure and purchased from Beijing Chemical Factory (Beijing, China). HPLC-grade acetonitrile and HPLC-grade methanol were purchased from Fisher (Fisher Scientific, Fair Lawn, NJ, USA). The ultrapure water was prepared from a gradient water purification system (Water Purifier, Sichuan, China). Eicosapentaenoic acid (EPA, Lot No: 32510020), docosahexaenoic acid (DHA, Lot No: 0501808), and arachidonic acid (ARA, Lot No: 2491801) were purchased from TanMo Quality Testing Technology Co., Ltd. (Beijing, China). α-Linolenic acid (ALA, Lot No: U-62A-J25-C), linoleic acid (LA, Lot No: U-52A-JA3-C), and oleic acid (OA, Lot No: U-46A-MA6-C) were purchased from ANPEL Laboratory Technologies (Shanghai) Inc. (Shanghai, China). The purity of each standard compound was higher than 99%, as determined by HPLC. Six kinds of PUFAs standards were formulated to different concentrations using HPLC-grade methanol and filtrated with a 0.22 μm filter membrane prior HPLC injection.
Jilin Province Rana Industry Association provided a total of 27 samples of Oviductus Ranae, which were collected from the Changbai Mountains area in Jilin Province, China. Collection sources covered the major production areas of Changbai Mountains. The specific collection information is shown in Table 1, and Figure 2 shows the geographical distribution of the samples.

Sodium 3-(trimethylsilyl)propionate-2,2,3,3-d₄ (batch no. 1668-E) was purchased from Merck. Deuterium oxide (D₂O) was purchased from Cambridge Isotope Laboratories. Methanol and acetonitrile (HPLC grade) were purchased from Beijing Chemical Works. Water (HPLC grade) was purchased from Hangzhou Wahaha Group. Dipotassium hydrogen phosphate (K₂HPO₄·3H₂O), sodium dihydrogen phosphate (NaH₂PO₄·2H₂O), and hydrochloric acid (analytical grade) were purchased from Beijing Chemical Works.