Simplicity system

The Roswell Park Memorial Institute (RPMI) 1640 medium and fetal bovine serum (FBS) were purchased from Gibco (Grand Island, NY, United States). The BCA assay kit was purchased from Sangon Biotech (Shanghai, China). Dithiothreitol (DTT, 3483–12–3), 2,2,2-trifluoroethanol (TFE, 99%, 75–89–8), acetaldehyde-¹³C2 (¹³CH₃¹³CHO, 99 atom % 13C, 1632–98–0), acetaldehyde (CH₃CHO, 99%, 75–07–0), sodium cyanoborohydride (NaBH₃CN, 25,895–60–7), ammonia solution (NH₄OH, 7664–41–7), acetonitrile (ACN, 75–05–8), formic acid (FA, 64–18–6), trypsin, and trifluoroacetic acid (TFA) were purchased from Sigma-Aldrich (St. Louis, MO, United States). Ultra-pure water was obtained on-site using the Millipore Simplicity System (Billerica, MA, United States). Ammonium bicarbonate (ABC) was purchased from Sangon Biotechnology (Shanghai, China). ZIC-HILIC particles were purchased from Thermo Fisher Scientific (Waltham, MA United States). PNGase F was purchased from New England Biolabs (Ipswich, MA, United States).

The following reagents were used: Chloroauric acid, neomycin trisulfate (NEO), Tween-20, biotinamidohexanoyl-6-aminohexanoic acid N-hydroxysuccinimide ester, sodium citrate (Sigma-Aldrich, St. Louis, MO, USA), streptomycin sulfate (AppliChem, Darmstadt, Germany), bovine serum albumin (BSA) (Boval Biosolutions, Cleburne, TX, USA), streptavidin (Arista Biologicals, Allentown, PA, USA), streptococcal protein G, goat anti-mouse antibodies (GAMI), and anti-mouse antibodies labeled with horseradish peroxidase (Imtek, Moscow, Russia). Anti-NEO monoclonal antibodies and the NEO–BSA conjugate, monoclonal antibodies to streptomycin, and the streptomycin–BSA conjugate were from Eximio Biotec (Wuxi, China). Salts, acids, and alkalis were of analytical or chemical grade. Solutions of GNPs and their conjugates were prepared using deionized water purified by the Simplicity system (Millipore, Billerica, MA, USA). The set of immunochromatographic membranes included the UniSart CN180 working nitrocellulose membrane (Sartorius, Goettingen, Germany), the GFB-R7L sample membrane, the AP-045 adsorption membrane, and the L-P25 plastic support (Advanced Microdevices, Ambala Cantt, India).

Acetonitrile, methanol, and formic acid for UHPLC were purchased from Merck (Darmstadt, Germany). Water for UHPLC was purified with a Millipore Simplicity System (Bedford, MA, USA). Solvents for the extraction of plant material were of analytical grade.

Acetonitrile, creatinine, VMA, HVA, Trp, 5-HIAA and indoxyl sulphate (IS) were purchased from Sigma–Aldrich (St. Louis, MO, USA), DHICA from Toronto Research Chemicals Inc. (Toronto, ON, Canada), formic acid from Riedel-de Haёn (Seelze, Germany). Ultrapure water was prepared by ultrafiltration of distilled water using the Simplicity system (Millipore, Molsheim, France). Mobile phase of 15% Acetonitrile (ACN:H₂O; 15:85) was prepared in deionised water with an addition of 0.05% formic acid. Stock solutions of creatinine, DHICA, VMA, HVA, Trp, 5-HIAA and IS were prepared by diluting given compounds to a concentration of 1 mg/ml in mobile phase. All reagents were of analytical grade.

Perylene, octadecylamine, poly (isobutylene-alt-maleic anhydride) M_w = 6000, tetrahydrofuran (THF), N, N-dimethylformamide (DMF), glucose, GOX, and invertase were purchased from Sigma-Aldrich (St. Louis, MO, USA). Meso-tetraphenyl-tetrabenzoporphine palladium complex (PdTPBP) was purchased from Fisher Scientific. Ultrapure water was prepared by using a Millipore Simplicity System (Millipore, Bedford, USA). All of the above-mentioned chemicals were used as received without further purification.

Anhydrous solvents and all reagents were purchased from Sigma-Aldrich, Alfa Aesar and TCI. The solvents used in MS measures were acetone, DMSO, acetonitrile (Chromasolv grade), purchased from Sigma-Aldrich (Milan, Italy), and mQ water 18 MΩ, obtained from Millipore’s Simplicity system (Milan, Italy).