Lc ms grade acetonitrile acn

LC–MS grade acetonitrile (ACN) and methanol (MeOH) were purchased from Fisher Scientific (Loughborough, UK). Formic acid was obtained from TCI (Shanghai, China). Chloroform was obtained from Sinopharm (Shanghai, China). Ultrapure water was generated using a Milli-Q system (0.22 μm, Millipore, Bedford, USA). 2-Amino-3-(2-chloro-phenyl)-propionic acid was obtained from Aladdin (Shanghai, China). Ultrahigh-performance liquid chromatography (UHPLC) and high-resolution mass spectrometry (HRMS) columns were supplied by Shenzhen Huada Genetics Co., Ltd. (Shenzhen, China).

LC‐MS grade acetonitrile (ACN) and methanol (MeOH) were purchased from Fisher Scientific (Pittsburgh, PA). Deionized water was purified by a Milli‐Q Ultrapure Water Purification System from EMD Millipore Corporation (Billerica, MA). Cyclocreatine (cCr), Creatine‐d3 monohydrate (98 atom % D) (Cr‐d3), pcCr, phosphocreatine‐d3 (pcCr‐d3), 3‐Guanidinopropinonic acid (≥99%) (GPA), ammonium acetate and formic acid were purchased from Sigma Aldrich (St. Louis, MO). pcCr and stable‐labeled internal standard (IS), cyclocreatine‐D4 [2‐(2‐imino‐4,4,5,5‐D4‐imidazolidin‐1‐yl)acetic acid] (cCr‐d4), were synthesized in‐house.6

LC–MS grade acetonitrile (ACN) was purchased from Fisher Scientific (Hampton, New Hampshire, United States). Gradient grade ethanol (EtOH) was obtained from Merck KGaA (Darmstadt, Germany). Hydrochloric acid 37%, LC-MS grade formic acid (FA) >99.9%,-folded qualitative filter paper 313, 15-mL polypropylene centrifuge tubes with screw cap and PTFE syringe filters (25 mm, 0.45 µm) were obtained from VWR (Radnor, Pennsylvania, United States). Sodium acetate solution 3-M in H₂O was purchased from Sigma-Aldrich (St. Louis, Missouri, USA). ST-20 Ultraturrax tubes and D6 SiLibeads were purchased from IKA-Werke (Staufen, Germany). cyanidin-3-O-glucoside chloride, cyanidin-3-O-sambubioside chloride and cyanidin-3-O-sambubioside-5-O-glucoside chloride reference standards were purchased from Extrasynthese (Lyon, France). Wild elderberry samples were collected in Tyrol (Austria) at the coordinates presented in Table S1 (Supplementary Materials). Each sample represents the berries attached to one umbel. The umbels were removed and after collection, the wild berries were frozen at minus 20 °C until processing and measurement. Because of the origin of the samples and considerable difficulties in harvesting wild elderberries, the collected sample set was limited to 27 samples (Table S1).

Standard compounds: LC-MS-grade acetonitrile (ACN), formic acid and methanol (MeOH) were obtained from Fisher Scientific (Fair Lawn, NJ, USA). LC-MS-grade water (18 MX) was prepared using a Millipore Milli-Q purification system (Millipore Corporation, Bedford, MA, USA).
High-performance liquid chromatography (HPLC) separation was performed using a Thermo Scientific^TM Dionex Ultimate 3000 LC system (Thermo Fisher Scientific, Waltham, MA, USA) with a Thermo Hypersil Gold aQ (1.9 µm, 100 mm × 2.1 diameter). A Thermo Scientific Q Exactive Focus (Thermo Fisher Scientific, USA) equipped with a pump: HGP-3200RS, Autosampler: WPS3000TRS, column compartment: TCC3000RS, a degasser: SRD3400, Diode Array Detector (DAD), Orbitrap mass analyser with a heated-electrospray ionization (H-ESI II), and software of Xcalibur and Chromaleon was used for LC-MS and LC-MS/MS detection.

Methanol (HPLC grade) and hexane (HPLC grade), used for sample extraction, were purchased from Fisher Scientific (Illkirch, France). The solvents used for liquid chromatography were LC-MS grade acetonitrile (ACN), obtained from Fisher Scientific. Deionized water was purified using a Milli-Q water (Millipore, Bedford, MA, USA) purification system.

LC-MS-grade acetonitrile (ACN), methanol, formic acid, and water were purchased from Fisher Scientific (Ottawa, ON, Canada).