N hexane hplc grade

Curcumae longae rhizomae pulv. subt. was purchased from Heinrich Klenk GmbH & Co. KG (Schwebheim, Germany). Carbon dioxide (Technical grade, ≥99.5%) was obtained from Westfalen AG (Muenster, Germany). Methanol (HPLC gradient grade) and n-hexane (HPLC grade) were purchased from Sigma-Aldrich Chemie GmbH (Taufkirchen, Germany). formic acid (HPLC grade) was obtained from Carl Roth GmbH + Co. KG (Karlsruhe, Germany). Acetonitrile (HPLC grade) was purchased from Honeywell Riedel-de-Haën AG (Seelze, Germany). Highly purified water for HPLC was produced using a Purelab Option Q7, Veolia Water Technologies Deutschland GmbH (Celle, Germany). Potassium carbonate, Hydranal-Methanol dry, and Hydranal-Composite 5 were purchased from Honeywell International Inc. (Charlotte, NC, USA)). Acetonitrile (LC-MS grade) and formic acid (98%) for LC-MS analyses were obtained from Sigma-Aldrich (Steinheim, Germany). Analytical standards of curcumin and ar-turmerone were obtained from Sigma-Aldrich Chemie GmbH (Taufkirchen, Germany) and α-turmerone was obtained from Toronto Research Chemicals (Toronto, ON, Canada).

All tocopherol homologues (purity > 95% by HPLC) were obtained from Calbiochem-Merck Biosciences (Darmstadt, Germany). n-Hexane (HPLC-grade), and 1.4-dioxane (HPLC-grade) were purchased from Merck (Darmstadt, Germany). All other solvents and chemicals used in this study were of analytical grade.

Dimethyl disulphide, iodine, 9cis-hexadecenoic acid methyl ester and the other commercially available cis and trans FAMEs and CEs were commercially available (Sigma Aldrich, Milan) and used without further purification. Pure samples of 6cis-16:1 and 7cis-16:1 were also commercially available (Lipidox, Sweden). Chloroform, methanol and n-hexane (HPLC grade, Merck) were used without further purification. Non-commercially available trans isomers as standard references were prepared and analyzed as previously described [22 (link), 28 (link)–30 (link)].

Absolute ethanol was obtained from Fisher Chemical (Loughborough, England). Methanol, gallic acid, Folin–Ciocalteu reagent, sodium carbonate (Na₂CO₃), boron trifluoride (BF3), and 1,4-dioxane were purchased from Sigma (St. Louis, MO, USA). Nitric acid (HNO₃), hydrogen peroxide (H₂O₂), Kjeldahl tablets catalyst, sulphuric acid, boric acid, potassium hydroxide (KOH), anhydrous sodium sulfate (Na₂SO₄), and n-hexane (HPLC grade) were obtained from Merck (Darmstadt, Germany). Tocol (2-methyl-2-(4,8,12-trimethyl-tridecyl) chroman-6-ol) was obtained from Matreya Inc. (State College, PA, USA). Vitamin E standards were from Calbiochem (La Jolla, CA, USA). Fatty acid methyl ester standard mixture (FAME) Supelco 37 was obtained from Supelco (Bellefonte, PA, USA). Water was purified in a Milli-Q system (Millipore, Bedford, MA, USA).

PAH4 (benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene) standards and the formaldehyde standard were purchased from Anpel Laboratory Technologies Inc. (Shanghai, China). All standards were 100 mg/L in concentration and the purity was ≥99%.
2,4-dinitrophenylhydrazine (DNPH), sodium acetate, acetic acid (analytical grade), and magnesium sulphate (guaranteed reagent) were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Acetonitrile (ACN) and methanol (HPLC grade) were supplied by Sigma-Aldrich Company (St. Louis, MO, USA), N-hexane (HPLC grade) was obtained from Merck (Darmstadt, Germany), and dichloromethane (DCM) (analytical grade) was purchased from TEDIA Company (Fairfield, OH, USA).
Primary secondary amine (PSA), particle size 40, octadecyl (C18) solid-phase extraction filler (particle size 40), was purchased from Aomi (Shandong) Technology Co., Ltd. (Jinan, China), and diatomaceous earth as a filling material was obtained from Merck (Darmstadt, Germany).

7890B-7000D gas chromatograph-tandem mass spectrometry and HP-5MS UI gas chromatography column (30 m × 0.25 mm, 0.25 μm, Agilent, USA); 6460 Triple Quadrupole LC/MS (Agilent, USA); Centrifuge 5810R High-speed centrifuge (Eppendorf, Germany); ME204/02 Electronic Balance (Mettler AG, Switzerland); EVA 50A Nitrogen Blow Instrument (Beijing Pritech Instrument Co., Ltd.); KS501 Shaker (IKA, Germany); Vortex -5 Vortex Mixer (China Qilinbel Instrument Manufacturing Co., Ltd.); MS 205DU electronic balance (accurate to 0.1 mg, Mettler AG, Switzerland).
155 species of pesticide residue standards (See Tables S1 and S2, purity ≥ 95%, Drehrenstorfer, Germany). Acetonitrile, n-hexane (HPLC grade, Merck, Germany); QuEChERS extraction kit 5982-5650 (anhydrous magnesium sulfate, anhydrous sodium acetate, sodium chloride) and purification tube 5982–-5256[N-propylethylenediamine (PSA), graphitized carbon black (GCB) and magnesium sulfate] were purchased from Agilent, USA; The test water was Milli-Q ultrapure water. The other reagents have reached analytical purity.

All chemicals were of the highest grade (analytical grade). N-hexane (HPLC grade), ethanol (purity > 98%), N, O-Bis(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylsilyl chloride (TMCS), polyethylene glycol (M_n: 6000), and castor oil were purchased from Merck KGaA, Darmstadt, Germany. Dimethyl sulfoxide (DMSO, GC grade, purity > 99.99%) was acquired from Sigma-Aldrich Co., St. Louis, MO, USA. 5-fluorouracil 1000 mg vial was purchased from Iran Darou, Tehran, Iran. Ultrapure Milli-Q water (18.2 MW) was used in all experiments.