Butyrophenone

Benzene (99.8%), toluene
(99.7%), chlorobenzene (99.7%), benzonitrile (99%), butyrophenone
(99%), 1-phenyl-2-butanone (98%), 4-phenyl-2-butanone (98%), retinol
(95%), pseudoionone (>90%), 2,6-dimethyl-2,4,6-octatriene (80%),
tetracene
(98%), pentacene (99%), and chloroform (99.9%) were purchased from
Sigma-Aldrich (Vienna, Austria). Benzo[a]pyrene (99.6%)
was from LGC Standard. Methanol (99.9%) and acetonitrile (99.9%) were
purchased from Honeywell. For the solid analytes (PAHs and retinol),
solutions with concentrations of 50 μmol/L were prepared in
pure solvents, while for the liquid analytes (benzene derivatives
and ketones) the concentration of the measured solutions was 0.01%
v/v. The head space of the volatile analytes (benzene derivatives
and ketones) was injected into the ionization source as vapor samples.
A syringe pump (KD Scientific, series 100, USA) was used to inject
the solutions with flow rate of 20 μL min^–1 into the nebulizer. A commercially available tune mix (ESI-L Low
Concentration Tuning Mix, G1969-85000, Agilent Technologies) was prepared
according to manufacturer instructions for tuning and accurate mass
calibration of the mass spectrometer.

All samples of nut-based milks (i.e., almond beverages, walnut beverage, peanut beverage, almond and cacao beverage) were obtained from the local market in Thessaloniki, Greece. All samples were stored in the refrigerator (+4 °C). Butyrophenone (purity ≥99%) was used as internal standard (IS) solution (Sigma-Aldrich, St. Louis, MO, USA). A stock solution of IS was prepared in methanol (Panreac, Barcelona, Spain) at a concentration of 1000 mg L⁻¹. A stock standard solution containing heptane (purity >99%, Sigma-Aldrich), a-pinene (purity >95%, Fluka, St. Gallen, Swiss), toluene (purity >99.8%, Sigma-Aldrich), 2-methylpyrazine (purity >99%, Sigma-Aldrich), 3-heptanone (purity >98%, Sigma-Aldrich), heptanal (purity >95%, Sigma-Aldrich), 2-octanone (purity >98%, Sigma-Aldrich), 1-heptanol (purity >98%, Sigma-Aldrich), benzaldehyde (purity >99%, Sigma-Aldrich) and 1-octanol (purity >99%, Sigma-Aldrich) was prepared in methanol (concentration of each analyte 1000 mg L⁻¹) and used for the identification of the volatile compounds and method validation. Τhe stock solution was stored in the refrigerator (+4 °C) and it was found stable for up to 2 months. Working standard solutions were prepared daily by diluting appropriate amount of stock standard solution and IS solution in distilled water.

Reference standard JAK01 (CPL409116) and its impurities (JAK07, JAK08, JAK09, JAK ImpA, JAK ImpB, JAK ImpC, JAK ImpD, JAK ImpE, and JAK SM-05) were manufactured in-house by Celon Pharma S.A. (Lomianki, Poland).
Mix reference substances to the distribution coefficient chromatographically determinations (CHI logD) including paracetamol, acetanilide, acetophenone, propiophenone, butyrophenone, and valerophenone (purity >99.0%) were purchased from Sigma-Aldrich Chemie GmbH (Steinheim, Germany).
Acetonitrile (ACN) (hypergrade for LC-MS), and methanol (MeOH, hypergrade for LC-MS) were purchased from Merck KGaA (Darmstadt, Germany), and dimethyl sulfoxide (DMSO, for HPLC) from POCH (Gliwice, Poland). Formic acid (98–100%, eluent additive for LC-MS) and ammonia (25% solution, eluent additive for LC-MS) were obtained from CHEM-LAB NV (Zedelgem, Belgium). Ultra-pure water for HPLC was obtained from the water purification system Milli-Q IQ 7000 from Merck KGaA (Darmstadt, Germany).

Log D (pH 7.4) was determined by chromatographic hydrophobicity index (CHI) measurements for the (S)-enantiomer of each SCRA involved in this study. A calibration mix of ten compounds at 10 µg mL⁻¹ in 1:1 (v/v) water:ACN was used (theophylline, phenyltetrazole, benzimidazole, colchicine, phenyltheophilline, acetophenone, indole, propiophenone, butyrophenone and valerophenone (all Sigma-Aldrich)). Test compounds were prepared at 0.25 mM in 1:1 (v/v) water:ACN. Samples (n = 2 for calibration standards; n = 1 for test compounds) were analysed using UPLC-PDA as described above. Retention times of calibration compounds are used to calculate retention factor (k), which is plotted against literature CHI values for each compound. Linear regression was performed to obtain a line of best fit, from which the CHI and subsequently CHI log D of calibration and test compounds are calculated. Calculations used and calibration data from CHI log D studies are provided in Section S3 of the supplementary information.