T butyl hydroperoxide t buooh

All solvents used in this study were of analytical grade. Methanol (MeOH), trifluoroacetic acid (TFA) and acetic acid were purchased from Merck Ltd. (Budapest, Hungary). Water was obtained from a Millipore (Bedford, MA, USA) Milli-Q water-purification system and used for the preparation of all aqueous solutions. Oxidizing agent t-butyl hydroperoxide (t-BuOOH was purchased from Sigma-Aldrich (St. Louis, MO, USA). Metalloporphyrines such as 5,10,15,20-tetrakis(2,3,4,5,6-pentafluorophenyl)iron(II) porphyrin (FeTPFP) and 5,10,15,20-tetrakis-(4-sulfonatophenyl)iron(II) porphyrin (FeTSPP) were purchased from Frontier Scientific (Logan, UT, USA). Amiodarone, tris(hydroxymethyl)aminomethane hydrochloride (Tris HCl), MgCl₂, glucose-6-phosphate, glucose-6-phosphate dehydrogenase, sodium acetate, potassium chloride (KCl) and NADPH were purchased from Sigma-Aldrich. Human liver microsomes pooled from mixed gender was obtained from Sekisui XenoTech Llc. (Kansas City, KS, USA). Magnetic nanoparticles with aminopropyl functions (MNPs-NH₂) were product of SynBiocat Llc. (Budapest, Hungary).

Synthetic motor oils from four manufacturers were provided by a local vendor (Table 1). Discrimination of non-degraded oil samples can be useful for identifying counterfeits and passing off a cheaper oil as higher quality oil. In this study, each of the high-end oils—SRS 5W30, 5W40, and 10W40—has its cheaper analog (LUK, EVE, and GAZ, respectively). Carbocyanine dye 1 (Cy7-hydrazine, CAS No. 2183440-61-9) was purchased from Lumiprobe (Hunt Valley, MD, USA, https://www.lumiprobe.com/, accessed on 1 September 2023), and dye 2 was synthesized by the authors according to published strategies (see Supplementary Materials for the synthetic protocol and spectral data). Ethanol was acquired from Bryntsalov-A (Moscow, Russia) and t-butyl hydroperoxide (t-BuOOH) from Sigma (as a 5 M solution in n-decane); it was diluted with ethanol (1:9, v/v) to obtain a 0.5 M working solution. Other reagents were bought from Sigma and used as received.