Dichlorometane

The chemicals used were β-carotene standard (Sigma, St. Louis, MO, USA); pyrogallol (99%; TCI, Tokyo Chemical Industry Co., Ltd., Tokyo, Japan); sodium chloride, potassium hydroxide (VWR International bvba, Leuven, Belgium); n-hexane (97% HPLC grade), tetrahydrofuran (99.7% HPLC grade; Avantor Performance Materials Poland S.A., Gliwice, Poland); ethyl acetate (99.7% HPLC grade; Sigma-Aldrich Co Chemie GmbH, Steinheim, Germany); ethanol (96%), methanol (HPLC grade), dichlorometane (stabilized with ethanol 0.1%; VWR International S.A.S., Fontenary-sous-Bois, France); butylated hydroxytoluene (Sigma-Aldrich Co., St. Louis, MO, USA).

All chemicals and reagents used, including the solvents, were of analytical grade. The solvents were distilled before use. Acetone (Ref.: 20066.330), methanol (MeOH, Ref.: 20903.368), sulfuric acid (H₂SO₄, Ref.: 470302.872), dichlorometane (DCM, Ref.: 23367.321), and dimethyl sulfoxide (DMSO, Ref.: 23486.322) were from VWR Chemicals). Other materials were hexane (Hex, Fisher Scientific, Ref.: H/0355/21), ethyl acetate (EtOAc; LabChem, Ref.: MP013-9025), trifluoroacetic acid (Sigma-Aldrich, Ref.: 8082600101), sand pure 40–100 mesh (Acrōs organics, Ref.: 370942500); MeOH HPLC grade (Fisher Scientific, Ref.: M/4056/17); ACN HPLC grade (Honeywell, Ref.: 608-001-00-3), K₂Cr₂O₇ (Labonal S.A., Ref.: 2635), and bidistillated water. Furthermore, filter paper (Whatman No. 5 paper, Inc., Clifton, NJ, USA), deuterated-chloroform 99.8 + 0.03% TMS (CDCl₃, Deutero.de-Rotoquímica, Ref.: 00405), and deuterated methanol (CD₃OD, Sigma Aldrich, Ref.: 1.06028) were used.