Acetone for hplc

Three different lignin samples were selected for this study. Softwood kraft Lignoboost was provided by Stora Enso (Finland). Hardwood birch lignin (Betula L.) was isolated using the BLN process, and obtained from CH Bioforce Oy (Espoo, Finland). Protobind 1000 was extracted from wheat straw by the soda process and acquired from GreenValue SA (Switzerland). Ethanol (Etax Aa, ≥99.5 %) was purchased from Altia Oy (Finland). Acetone for HPLC (≥99.9 %), acetyl bromide, vanillin, syringaldehyde, and citric acid monohydrate were acquired from Sigma‐Aldrich (Finland). Acetic acid (glacial) 100 % for analysis EMPARTA® ACS, Folin‐Ciocalteu reagent, and sodium carbonate were purchased from Merck (Finland). NMR solvent DMSO‐d6 was acquired from Eurisotop (Saint‐Aubin, France).

HPLC for the UV gradient-grade acetonitrile was purchased from J.T. Baker (Phillipsburg, NJ, USA). Acetone for HPLC and ammonium formate, from Sigma-Aldrich, and LiChrosolv methanol hypergrade for LC-MS, Emplura n-hexane, and LiChropur formic acid for LC-MS were purchased from Merck (Darmstadt, Germany). Ultrapure water (18.2 MΩ cm) was obtained from a Milli-Q Academic A10 Water Purification System (Millipore Ltd., Bedford, MA, USA). QuEChERS reagents, SupelTM QuE Citrate Tube containing anhydrous magnesium sulphate (MgSO₄), sodium chloride (NaCl), trisodium citrate dihydrate (NaCitrate tribasic dehydrate), disodium hydrogencitrate sesquihydrate (NaCitrate dibasic sesquihydrate), and clean-up mixture SupelTM QuE PSA Tube containing primary secondary amine sorbent (MgSO₄ + PSA) were purchased from Supelco (Bellefonte, PA, USA). High-purity pesticide analytical standards (Dr. Ehrenstorfer, Augsburg, Germany) were purchased from LGC (Teddington, UK) and were stored at −20 °C in dark conditions.

The components of an aqueous solution comprised of ammonia ≥27.5%, iron(II) chloride tetrahydrate ≥98.5%, iron(III) chloride hexahydrate ≥99%, anhydrous calcium chloride ≥99%, sodium carbonate ≥99%, ciprofloxacin ≥ 98.0% (HPLC), ethyl alcohol 99%, acetone for HPLC, crystal violet for biological stain, were obtained from Sigma–Aldrich (St. Louis, MO, USA). Deionized water 15 MOhm was produced with MilliQ Millipore Elix 3 system.