Potassium hydroxide

Nickel chloride hexahydrate (NiCl₂.6H₂O), hexamethylenetetramine (HTMA), and polyethyleneimine (PEI), were purchased from Sigma-Aldrich, Darmstadt, Germany. Acetone and isopropanol-99.9% (IsPOH) were acquired from Walter CMP Gmbh (Kiel, Germany). Additionally, 25% ammonium hydroxide (NH₄OH) and potassium hydroxide (KOH) were supplied by Carl Roth Gmbh (Karlsruhe, Germany). All chemicals were of analytical-grade purity. All solutions were prepared with deionized water (≥18 MΩ/cm).

All chemicals were used without further purification. Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) was purchased from Sigma Aldrich (Munich, Germany), and bromination was conducted in the same way as described previously [28 (link)]. Poly[(1-(4,4′-diphenylether)-5-oxybenzimidazole)-benzimidazole] (PBI-OO) was purchased from FuMA-Tech GmbH (Ludwigsburg, Germany). Sulfonated polymer was synthesized as previously reported in the literature [29 (link)]. 1,2,4,5-tetramethylimidazole was purchased from TCI chemicals. N,N-Dimethylacetamide (DMAc) and methanol were obtained from VWR International GmbH (Bruchsal, Germany). Sulfuric acid, potassium hydroxide, 0.1 N standard hydrochloric acid, and sodium hydroxide were purchased from Carl Roth GmbH (Karlsruhe, Germany). Vanadium electrolyte was provided by RIVA GmbH Batteries. The structures used in this study are presented in Figure 1.

Adenine, aluminum chloride, potassium hydroxide, sodium nitrate, and Folin–Ciocalteu reagent were purchased from Carl-Roth (Germany). 2, 2-Diphenyl-1-picrylhydrazyl (DPPH), (2′, 2′-azobis (2-methylpropionamidine) dihydrochloride) (AAPH), gallic acid, quercetin, ascorbic acid, Tris, hydrogen peroxide, trichloroacetic acid, ferric chloride, and hydrogen chloride were purchased from Sigma–Aldrich (Germany). Captopril was purchased from Denk Pharma GmbH and Co., KG (Germany). Thiobarbituric acid was from Fluka. Sodium chloride and potassium chloride were purchased from BDH Chemicals Ltd. (England). Creatinine, urea, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) kits were purchased at SGM Italia (Roma). Sodium thiopental was from Samarth Life Sciences Pvt Ltd. (Mumbai).

PPFSt was prepared as described in our earlier study [13 ]. F6-PBI was purchased from Yanjin Technology, Shenzhen, China. Sulfuric acid, methyl ethyl ketone, potassium hydroxide, 0.1 N standard hydrochloric acid and sodium chloride were purchased from Carl Roth GmbH, Karlsruhe, Germany. N-methyl-2-pyrrolidone (NMP) and diethyl ether were obtained from Sigma-Aldrich, Munich, Germany. N,N-dimethylacetamide was purchased from Acros Organics, Darmstadt, Germany. Sulfuric acid was purchased from VWR International, Bruchsal, Germany. 1-(2-dimethylaminoethyl)-5-mercaptotetrazole (DMAEMTZ) and triethylamine were purchased from TCI Chemicals, Eschborn, Germany. Iodomethane was purchased from Merck, Darmstadt, Germany. The vanadium electrolyte solution (1.6 M vanadium in 30% Sulfuric acid: 50% VO²⁺ and 50% V³⁺) was supplied by RIVA GmbH Batteries, Backnang, Germany. Nafion^®212 (Nafion) was purchased from Ion Power GmbH, Munich, Germany.

(RS)-Amphetamine and racemic norephedrine-d3 were purchased from LGC (Wesel, Germany). (RS)-Amphetamine d11, (S)-amphetamine, (R)-amphetamine, racemic norephedrine and (RS)-4-hydroxyamphetamine were obtained from Lipomed (Weil am Rhein, Germany). Methanol (HPLC-grade) was purchased from Thermo Fisher Scientific (Dreieich, Germany). Water (LC-MS-grade), acetonitrile, dichloromethane, acetone, isopropanol, glacial acetic acid, potassium dihydrogenphosphate and potassium hydroxide were obtained from Carl Roth (Karlsruhe, Germany). LC-MS-grade ammonia solution (25%) and ammonium bicarbonate were purchased from Merck (Darmstadt, Germany). All chemicals were at least of analytical grade. Mixed-mode cation-exchange solid-phase extraction columns (HF BE-CERTIFY, 300 mg, 3 mL) were purchased from Agilent (Waldbronn, Germany). Round-robin tests ‘BTMF—Drugs in serum’ containing certified racemic amphetamine were acquired from Arvecon (Walldorf, Germany). Blank (drug-free) serum was provided by the blood bank of the University Medical Center of the Johannes Gutenberg University Mainz.