Chromasolv lc ms

Water (Chromasolv^® LC–MS), acetonitrile (Chromasolv^® LC–MS), methanol (Chromasolv^® LC–MS), gabapentin and formic acid were purchased from Sigma-Aldrich (Steinheim, Germany); (±)–baclofen was purchased from Polpharma SA (Starogard Gdański, Poland). Standard solutions of baclofen were prepared in water. gabapentin [internal standard(IS)] was prepared in methanol. The standard solutions were stored in a refrigerator at −20 °C.

Water (Chromasolv^® LC–MS), acetonitrile (Chromasolv^® LC–MS), and formic acid were purchased from Sigma-Aldrich (Steinheim, Germany); ammonium formate was purchased from Sigma-Aldrich (Bangalore, India); amphetamine, methamphetamine, amphetamine-d₁₁ (IS), methamphetamine-d₅ (IS), diazepam-d₅ (IS) were purchased from Cerilliant (Round Rock, TX, USA).

The extraction process was carried out as previously reported by [20 (link)], with solvent modifications. The frozen samples were thawed and then subjected to an extraction process based on two different extraction solvents: methanol and dichloromethane. To this aim, milk samples were skimmed by centrifugation at 4500× g for 10 min at 4 °C, then a 5 mL aliquot was put in contact with 10 mL of a methanol solution acidified with 3% formic acid. In parallel, another 5 mL aliquot of milk was mixed with 10 mL of dichloromethane acidified with 3% formic acid. Both extraction mixtures were centrifuged at 5000× g for 15 min at 4 °C (Thermo Scientific SL 40FR). Subsequently, the recovered supernatant was dried under a nitrogen stream, then resuspended in 1 mL of acetonitrile (LC-MS Chromasolv, ≥99.9% purity, Sigma-Aldrich) and filtered using a 0.22 µm cellulose membrane into amber vials for metabolomic analysis.

LC-MS grade methanol (LC-MS LiChrosolv^®, Merck (≥99.97%), formic acid (98–100%), water (LC-MS Chromasolv), trans-zeatin (≥97%), solasodine (≥95%), tomatidine hydrochloride (≥85%), α-solanine (≥95%), solanidine (≥95%), phenylalanine (≥98%), tyrosine (≥98%), tryptophan (≥95%), methyl dihydrojasmonate (≥96%), and DMSO (≥99.9%) were purchased from Sigma-Aldrich (St. Louis, MO, United States) and α-chaconine (≥95%) (PhytoLab, Germany).

Ginger, roughly ground, was purchased from Alfred Galke GmbH (Samtgemeinde Bad Grund, Germany) and industrial hemp (leaf and bud) was purchased from local growers in Slovenia. The type of hemp was Kc Dora, which was air dried at 38 °C. Kc Dora is characterized by a vegetative cycle of 145 days and grows up to 250 cm.
The chemicals used were 2,2-diphenyl-1-picrylhydrazyl (DPPH) (Sigma Aldrich, Darmstadt, Germany, ≥97.0%), carbon dioxide (Messer; MG-Ruše, Slovenia, purity 2.5), chloric acid (HCl), (Sigma Aldrich, 37%), dimethyl sulfoxide (DMSO), ethanol (EtOH), (Sigma-Aldrich, HPLC grade, ≥99.9%), ferrous sulfate heptahydrate (Fe(SO₄) × 7 H₂O) (Sigma Aldrich), Folin-Ciocalten reagent (FC), (Sigma Aldrich), gallic acid (Sigma Aldrich, 97.5–102.5%), methanol (MeOH), (Honeywell, Charlotte, NC, USA, LC-MS CHROMASOLV^®, ≥99.9%), n-butanol (Sigma Aldrich, ≥99.5%) and sodium(V)carbonate (Na₂CO₃), (Sigma Aldrich, ≥99.9%).

Chemical standards were from Sigma-Aldrich (Saint Quentin Fallavier, France). Liquid chromatography solvents, i.e., acetonitrile (ACN) and water, and extraction solvent (i.e., methanol) were LC-MS grade solvents (LC-MS Chromasolv, Sigma-Aldrich, Saint Quentin Fallavier, France). Mobile phase additive (i.e., formic acid) was from Sigma Aldrich. NIST SRM-1950 reference plasma was ordered from the National Institute of Standards and Technology (NIST, Gaithersburg, MD, USA).