N hexane

Forty-two batches of Radix Bupleuri samples that were cultivated for two years were collected during September and October in 2021 from different cultivation regions in China, including Sanyuan County (SY) in Shaanxi Province, Shouyang County (SA) and Qingyang City (QY) in Gansu Province, Xinjiang County (XJ) and Wanrong County (WR) in Shanxi Province, Chengde City (CD) in Hebei Province, and Wuzhong City (WZ) in Ningxia Province. Their botanical origins were all authenticated to Bupleurum chinense DC by Professor Shumin Wang of Changchun University of Chinese Medicine, China. Authentic standards of SSa, SSd, SSc, SSe, and SSf were purchased from Shanghai Yuanye Biological Technology Co., Ltd. (Shanghai, China). HPLC-grade methanol, acetonitrile, and n-hexane were acquired from Tedia Company, Inc. (Fairfield, CT, USA), while formic acid was purchased from Thermo Fisher Scientific (Waltham, MA, USA). Analytical grade methanol, ammonia, and n-butanol were bought from Beijing Chemical Industry Group Co, Ltd. (Beijing, China). Ultrapure water was prepared by Milli-Q water purification apparatus (Merck Millipore, Bedford, OH, USA).

Major reagents included the mixed standard solution of 16 priority PAHs: Naphthalene (Nap), Acenaphthylene (Acy), Acenaphthene (Acp), Fluorene (FLR), Phenanthrene (PHE), Anthracene (Ant), Fluoranthene (FLT), Pyrene (PYR), Chrysene (CHR), Benzo [a] anthracene (BaA), benzo[k]fluoranthene (BkF), Benzo[a]pyrene (BaP), Benzo[b]fluoranthene (BbF), Dibenz[a,h]anthracene (DhA), Benzo[ghi]perylene (BgP), and Indeno[1,2,3,cd]pyrene (IcP). The mixed standard solution was purchased from AccuStandard Company, New Haven, CT, USA. Chromatography-grade n-hexane and dichloromethane as an extract and eluent of PAHs were purchased from TEDIA Company, Fairfield, OH, USA. The anhydrous Na₂SO₄ was purified and activated prior to analysis in a muffle furnace at 400 °C for 4 h. The internal standard compound, Philippine-d₁₀, was purchased from the J & K Company (San Jose, CA, USA). The internal standard compound was a pure substance, and the contents of the measured components were determined by comparison. Copper powder and silica gel were purchased from the National Pharmaceutical Group (Beijing, China). All other chemicals were analytical grade.

Chlorfenapyr standards (98.6%) were purchased from Tan-Mo Technology Co., Ltd., Changzhou, China. Tralopyril standards (98.6%) were purchased from Dr. Ehrenstorfer GmbH, Germany. Sodium chloride (AR) was purchased from Sinopharm Chemical Reagent Co., Ltd., Shanghai, Chian. PSA and GCB were purchased from Tianjin Bonaijer Technology Co., Ltd., Tianjin, China. Anhydrous sodium sulfate (AR) was purchased from Shanghai Runjie Chemical Reagent Co., Ltd., Shanghai, China. Chromatographically pure n-hexane and acetonitrile were purchased from Tedia Co., Ltd., Fairfield, USA. The Chlorfenapyr standard and Tralopyril standard were dissolved in n-hexane and acetonitrile to prepare a stock solution with a concentration of 1000 mg/L, stored at 4 °C in the dark. Diluted to different concentrations when used.

PAN powder, used without purification, was given by Tong-Hwa Synthesis Fiber Co. Ltd. (Taipei, Taiwan). The monomers for interfacial polymerization were as follows: p-phenylenediamine, C₆H₄ (NH₂)₂ (PPD, Alfa Aesar, Heysham, Lacashire, UK); ethylenediamine, C₂H₄(NH₂)₂ (EDA, Alfa Aesar, Heysham, Lacashire, UK); 1,4-cyclohexanediamine, C₆H₁₄N₂ (CHD, Tokyo Chemical Industry Co. Ltd., Tokyo, Japan); and trimesoyl chloride, C₉H₃Cl₃O (TMC, Tokyo Chemical Industry Co. Ltd., Tokyo, Japan). N-methyl-2-pyrrolidone and n-Hexane were solvents of PAN and TMC, respectively, and were procured from Tedia Company Inc. (Fairfield, OH, USA). Salts (MgCl₂, MgSO₄, Na₂SO₄, and NaCl) were purchased from Sigma-Aldrich (Saint Louis, MO, USA). Two commercial membranes (NF90 and NF270) were bought from DuPont, Taiwan. Brilliant blue R, as dye, was provided by Tokyo Chemical Industry Co. Ltd. (Tokyo, Japan). The distilled water was laboratory-produced using a Lotun Technic machine (Lotun Technic Co. Ltd., New Taipei, Taiwan).

Plant VOCs were collected with a closed loop dynamic headspace sampling system, similar to the method described by Sun et al.59 (link). One milliliter of n-Hexane (Tedia, USA) was applied to elute VOCs from absorbent traps and 1300 ng Nonyl acetate (Sigma, Switzerland) was added to each sample as an internal standard. VOCs emitted from the Xoo infected rice and control rice plants were collected for 24 h (16 h in light and 8 h in darkness) at room temperature; BPH-induced plant volatiles from rice plants (each rice plant was also infested with 15 gravid female adults for 24 h) were collected for 8 h in the light (20000 lx) as described by Lou et al.60 (link). Each treatment contained three to five biological replicates.
Gas chromatography–mass spectrometry (GC/MS) analyses of VOCs were performed on a QP-2010 GC/MS instrument (Shimadzu, Japan) equipped with an HP-5 MS fused-silica column (30 m × 0.25 mm × 0.25 μm). (Agilent Technologies, http://www.agilent.com). Helium (1 ml/min) was used as the carrier gas, and the initial oven temperature was 40 °C, held for 1 min, ramped at 8 °C min⁻¹ to 300 °C held for 5 min. VOCs were identified by comparing their GC retention indices and MS spectra with those from the NIST11 library. The Retention index for each compound was determined using a series of straight chain alkanes (C7-C30) as standards.

Five PAE analytical standards (≥99.0%) of DMP, DEP, DiBP, DBP, and DEHP were purchased from Dr. Ehrenstorfer GmbH (Augsburg, Germany). Optima GC–MS grade toluene, acetonitrile, and n-hexane were purchased from Tedia Co., Inc. (Fairfield, OH, USA). Analytical grade sodium chloride and anhydrous ethanol were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Solid-phase extraction glass columns (CARB/NH₂, 1000 mg/6 mL) were purchased from Dikma Technologies Inc. (Beijing, China).
To remove possible cross-contamination of PAEs, all glassware and chinaware used in the study were immersed in methanol overnight, rinsed with hexane, and dried at 140 °C for at least 4 h. Organic solvents were redistilled before being used. Sodium chloride was heated at 450 °C for 4 h in a muffle furnace and kept in sealed glass vials after cooling. For PAE analysis, a procedural blank and solvent blank were run with every batch of samples for quality assurance and quality control.