Homofuraneol

Sotolone (3-hydroxy-4,5-dimethyl-2(5H)-furanone), maple furanone (5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone), furaneol (4-hydroxy-2,5-dimethyl-3(2H)-furanone) and homofuraneol (mixture of 5-ethyl-4-hydroxy-2-methyl-3(2H)-furanone and 2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone) and other reagents were purchased in analytical grade from Sigma-Aldrich, Steinheim (Germany).

The deuterated internal standards of caffeic acid-d₆ (CAS 2708298-33-1, ≥99%) and furfural-d₄ (CAS 1219803-80-1, ≥98%) were purchased from CDN Isotopes (Pointe-Claire, QC, Canada). furfural ethyl ether (CAS 6270-56-0, ≥97%) was purchased from Fisher Scientific (Hampton, NH, USA). The following compounds were purchased from Sigma-Aldrich Inc. (Oakville, ON, Canada); caffeic acid (CAS 331-39-5, ≥98%), caftaric acid (CAS 67879-58-7, ≥97%), 3-acetyl-2,5-dimethylfuran (CAS 10599-70-9, ≥98%), 2-furanmethanethiol (CAS 98-02-2, ≥98%), 2,3-dihydrobenzofuran (CAS 496-16-2, ≥99%), 2-acetylfuran (CAS 1192-62-7, ≥99%), 5-methylfurfural (CAS 620-02-0, ≥98%), homofuraneol (CAS 27538-09-06, ≥96%), furfural (CAS 98-01-1, ≥99%), sodium chloride (NaCl, ≥99%) and ethyl-2-furoate (CAS 614-99-3, ≥99%). All solvents used were HPLC grade purity. Potassium metabisulphite (KMS) and potassium bitartrate (cream of tartar) were purchased from Scott Laboratories Ltd. (Niagara-on-the-Lake, ON, Canada). D-fructose (≥99%) was purchased from BioShop^® Canada Inc. (Burlington, ON, Canada). Milli-Q water was obtained Millipore (Saint-Quentin-en-Yvelines, France).