Phosphoric acid

Methanol (HPLC grade) was purchased from J. T. Baker (Deventer, The Netherlands); toluene, phosphoric acid (85%) and hydrochloric acid (37%) were obtained from Honeywell (Charlotte, NC, USA); 2, 2, 2-trimethyl pentane (≥99%, ACS reagent), 1-butanol, sodium chloride, sodium hydroxide, ammonium iron (III) citrate, carboxymethyl cellulose (CMC), alpha-pinene (98%), beta-pinene (99%), myrcene (99%), limonene (99%), linalool (97%), alpha-terpineol (99%), beta-cutronellol (99%), nerol (98%), geraniol (98%), geranyl acetate (98%), beta-caryophyllene (99%), alpha-humulene (CRM) and caryophyllene oxide (95%) were purchased from Sigma Aldrich (St. Louis, MO, USA); ethylenediaminetetraacetic acid (EDTA) was obtained from Merck (Kenilworth, NJ, USA); international calibration extract 4 (ICE4), DCHA-Iso and DCHA-Humulinones were obtained from Labort Veritas (Zürich, Switzerland). Light Malt Extract was procured from Muntons (Lombard, Chicago, IL, USA).

Preparation of the test solutions: vancomycin chlorhydrate and ceftazidime pentahydrate powders were obtained from Vancomycin Mylan^® and Ceftazidime Mylan^® powder for injectable solution vials (Mylan, Cournon-d’Auvergne, France). Deionized water (Versylene^®) was purchased from Fresenius Kabi (Louviers, France). HP-β-CD (CAS 128446-35-5) and HP-γ-CD (CAS 128446-34-4) were obtained from Sigma-Aldrich (St. Louis, MO, USA). Sodium dihydrogenophosphate dihydrate (NaH₂PO₄) (Batch 190298040, exp. 30 November 2021), and disodic monohydrogenophosphate dodecahydrate (Na₂HPO₄) (Batch 18129611, exp. 30 April 2023) were provided by Inresa (Bartenheim, France). Phosphoric acid at 850 mg mL⁻¹ (H₃PO₄), and sodium hydroxide at 320 mg mL⁻¹ (NaOH) (CAS: 1310-73-2), were purchased from Honeywell (Germany). Finally, deuterated water (D₂O) and Tetra Deuteriated TrimethylSilylPropionate (TSPd₄) were purchased from Eurisotop (St. Aubin, France).

Standards of gallic acid, quercetin, cyanidin chloride, caffeic acid, quercetin-3-O-glucoside and tryptophan were purchased from Sigma-Aldrich (Saint-Quentin Fallavier, France). Folin-Ciocalteu’s reagent (10%), aluminum chloride (AlCl₃) (10%), potassium acetate (1 M), DPPH, Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), ABTS (7 mM), potassium persulfate (2.45 mM), ferric chloride (FeCl₃·6H₂O), 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ), methyl-tert-butyl-ether (MTBE),2,2’-Azobis(2-amidinopropane) dihydrochloride (AAPH), fluorescein, sodium nitroprusside (5 mM), sulphanilamide, n-(1-naphthyl) ethylenediamine dihydrochloride phosphate buffered saline (PBS) acetate buffer, phosphate buffer, and mEthanol were supplied by Sigma-Aldrich (Saint-Quentin Fallavier, France). Ethanol, hexane, acetone, formic acid, and sodium carbonate (75 g/L), were purchased from Carlo Erba Reagents (Val de Reuil, France); hydrochloric acid, butanol, acetonitrile, ethyl acetate, phosphoric acid, and ferric ammonium sulfate (2%) were from HoneyWell Riedel-de Haën (Seelze, Germany). All solvents were of the highest analytical grade.

Ketoprofen (≥98.0%, KET), naproxen (≥98.0%, NAP), sodium diclofenac (≥98.5%, DCF), and indomethacin (≥98.5%, IND) were purchased from Sigma-Aldrich (Darmstadt, Germany) and used as model analytes. Phosphoric acid (Honeywell, Morris Plains, NJ, USA), acetonitrile (ACN), and methanol (MeOH) (VWR, Paris, France) served as mobile phase modifiers. The standard solutions were acidified by acetic acid from Penta (Prague, Czech Republic). The proteinaceous matrix was prepared by dissolution of lyophilized human serum Lyo hum N (Erba Lachema, Brno, Czech Republic). Water was purified by Millipore Milli-Q Direct Water Purification System from Merck (Darmstadt, Germany). The composite poly-ε-caprolactone sorbent was fabricated at the Technical University of Liberec from poly-ε-caprolactone (Mw 43.000) provided by Polysciences (Heddesheim, Germany), and chloroform (≥97%) and ethanol (99.97%) bought from Penta Chemicals (Pardubice, Czech Republic).

Ethanol, sulfuric acid, and phosphoric acid, all of which were of analytical grade from Honeywell (Seelze, Germany), were used in the process. Sodium metabisulfite, used to stabilize the chlorogenic acids during the assays, was of analytical grade and was purchased from Sigma Aldrich (Steinheim, Germany). Chlorogenic acid was purchased from Biopurify (Chengdu, China). Trigonelline, sodium 3-(trimethylsilyl)-[2,2,3,3-d4]-1-propionate (TSP), deuterium oxide, and other chemicals used were purchased from Merck Millipore (Burlington, Massachusetts, USA). Coffee husks from the wet depulping and demucilaging process of coffee beans (Coffea arabica) were cleaned until water was clear. Raw coffee husk was split into lots of 3 kg and kept in a freezer at −20 degrees Celsius prior to experiments; batches of 1 kg of coffee husk were thawed at room temperature when needed.