Barnstead tii super pure water system

Fresh SMB roots (PS01–PS12) were obtained from Mianchi (Henan, China), Fengxiang, Baoji, Shangnan, Luonan, Linyou, Baishui, Shanyang, Shangzhou, Tongguan, Huayin (Shaanxi, China) from Shaanxi Tasly Pharmaceutical Co. Ltd. Reference standards Tan I (HPLC ≥ 98%), Tan IIA (HPLC ≥ 98%), CTS (HPLC ≥ 98%) and DTS (HPLC ≥ 98%) were obtained from the Shanghai Yuanye Biotechnology Co. Ltd. (China). Chloroform-D (CDCl₃) were purchased from Qingdao Asfirst Science Co. Ltd. (D, 99.8%, Qingdao, China), 3,4,5-trichloropyridine were purchased from Shanghai Aladdin Bio-chemical Technology Co. Ltd. (GC, 98%, Shanghai, China), in which CDCl₃ was used as solvent and 3,4,5-trichloropyridine was used as the internal standard (IS). Methanol and acetonitrile of chromatographic grade (TEDIA) were used for extraction and HPLC analysis. Analytical grade phosphoric acid (Damao Chemical Reagent Factory, Tianjin, China) was used for the HPLC analysis. The pure water used in this study was obtained using a Barnstead TII Super Pure Water System (Thermo Fisher Scientific, Boston, MA, USA).

OS was collected from Yunnan Kunming in June 2017 and stored at room temperature until analysis. The reference standards of PCA, CAA, RA and chloramphenicol (CHL, IS) were purchased from Aladdin Chemistry (Shanghai, China). DSS was purchased from National Institutes for Food and Drug Control (Beijing, China). CA, Sal A, Sal B, SIN and EUP were purchased from Chengdu Weikeqi Bio-Technology Co., LTD (Chengdu, China). L-Ascorbic acid (VC) was purchased from Shanghai Macklin Biochemical Co., Ltd. (Shanghai, China). The purities of all the reference standards were higher than 97%. HPLC grade acetonitrile and methanol were supplied by Merck (Darmstadt, Germany). Formic acid of HPLC grade was supplied by Aladdin Chemistry (Shanghai, China). Ultrapure water was produced by Barnstead TII super Pure Water System (Thermoscientific, Massachusetts, USA). All other analytical grade chemicals used in this experiment were purchased from Yongda Chemical Reagent Company (Tianjin, China). The chemical structures of these compounds are shown in Scheme 1.