Simplicity water purification system

Six of the seven cannabinoid analytes [∆⁹-THC, cannabinol (CBN), cannabigerol (CBG), cannabigerolic acid (CBGA), ∆⁹-tetrahydrocannabinolic acid A (∆⁹-THCA), and ∆⁹-tetrahydrocannabivarin (∆⁹-THCV)] and the internal standard (IS; ∆⁹-THC-D₃) were obtained as certified reference materials (CRMs) manufactured by Cerilliant (Round Rock, TX). Cannabichromene (CBC) was obtained as a CRM from Cayman Chemical (Ann Arbor, MI). When not in use, concentrated stock solutions of these agents and working solutions made therefrom were stored at –20 °C.
Acetonitrile, formic acid, methanol, and n-hexane were purchased from Thermo Fisher Scientific and were of LC/MS grade. Ethyl acetate (Acros Organics) was purchased from Thermo Fisher Scientific and was of spectroscopy grade (> 99.5%). High purity water (18.2 MΩ) required for preparing the mobile phase and for sample extraction was produced using an EMD Millipore Simplicity water purification system. When not in use, these agents were stored at room temperature (20–25 °C). Nitrogen (N₂), supplied as a cryogenic liquid in a 230L dewar at a purity of 99.998%, or as compressed nitrogen gas at a purity of 99.999% in T-type cylinders, was obtained from Praxair (Danbury, CT).

PS₃₅-b-PEG₁₁₅ (Sample #: P10086B-SEO), PMMA₅₅-b-PEG₉₅ (Sample #: P5164-EOMMA), PBd₉₀-b-PEG₁₃₀ (Sample #: P4603-BdEO), PE₄₀-b-PEG₈₅ (Sample #: P3288-EEO), and PDMS₁₅-b-PEG₁₁₅ (Sample #: P7261-DMSEO) were purchased from Polymer Source, Dorval, QC, Canada; PCL₄₅-b-PEG₁₁₅ was purchased from Sigma-Aldrich, St Louis, MO, USA (Product number: 570303). Ratios of DP(PEG)/DP(hydrophobic block) for all the block copolymers (except for PE-b-PEG) were calculated from ¹H NMR spectra (Bruker Avance 400 spectrometer; Bruker, Ettlingen, Germany); all spectra were measured in DMSO-d₆ at room temperature.
N,N-dimethylformamide (DMF; Ekos-1, Moscow, Russia) and dimethylsulfoxide (DMSO; Vecton, Saint Petersburg, Russia) were distilled in vacuum using standard procedures. Tetrahydrofuran (THF) and 1,4-dioxane were purified by distillation over sodium hydroxide in argon atmosphere. Acetonitrile (chromatographic “0” grade; KryoChrom, Saint Petersburg, Russia) and N-methylpyrrolidone (NMP; Sigma-Aldrich, St Louis, MO, USA) were used as received. Water was purified using a Simplicity water purification system Merck Millipore, San Jose, CA, USA (type 1 water).

Lignosulfonic acid sodium salt (LS, Mw ~52,000 and Mn ~7000) and tannic acid (TA, C₇₆H₅₂O₄₆, from Chinese natural gall nuts) were acquired from Sigma-Aldrich (St. Louis, MO, USA). Ultrapure water (Type 1, 18.2 MΩ cm at 25 °C) was purified by a Simplicity^® Water Purification System (Merck, Darmstadt, Germany). Additional chemicals or solvents were of laboratory grade.
Bacterial nanocellulose (BNC), entailing a three-dimensional network of nano- and micro-fibrils with 10–200 nm width, was biosynthesized in the form of wet membranes (99.5% of water) by the Gluconacetobacter sacchari bacterial strain [6 (link)].

A 10 wt% dimethylformamide (DMF) dispersion of the PFSA polymer with equivalent weight of 1100 in the Li⁺ form (MF-4SC, Plastpolymer, Saint-Petersburg, Russia) and multiwall CNTs (Taunit S12, NanoTechCenter, Tambov, Russia) were used. Nitric acid (special purity, >70%), acetone (reagent grade, >99.75%), hydrochloric acid (special purity, 35–38%), and potassium chloride (reagent grade) were bought in Chimmed (Moscow, Russia). D-glucose (Ph Eur, hydrated form, Merck, Darmstadt, Germany), p-toluenesulfonic acid (97.5%, Acros Organics, Geel, Belgium), ethanol (95%, Ferein, Minsk, Belarus), and 3-aminopropyl)trimethoxysilane (97%, Alfa Aesar, Ward Hill, MA, USA) were used. N-[(4-aminophenyl)sulfonyl]acetamide (>99%) and 4-aminobenzenesulfonamide (>99%) were supported from Sigma-Aldrich (Saint-Louis, MO, USA). Sulfacyl sodium-SOLOpharm eye drops (Grotex, Saint-Petersburg, Russia) were analyzed. The deionized water with resistance 18.2 MΩ and pH 5.41 ± 0.05 was obtained using a Simplicity^® Water Purification System (MerckMillipore, Darmstadt, Germany).

Albumin from human serum (≥99%), α1-acid glycoprotein from human plasma (≥99%), trypsin from porcine pancreas (proteomics grade), DL-dithiothreitol (DTT) (≥99.5%), iodoacetamide (≥99%), ammonium bicarbonate (≥99%), LiChrosolv^® water, LC-MS grade acetonitrile, phosphate buffered saline (PBS), and formic acid were purchased from Merck (Darmstadt, Germany). RapiGest SF surfactant and Leucine enkephalin were obtained from Waters (Milford, MA, USA). Acrylamide (≥99%) was obtained from Acros Organics (Antwerp, Belgium). Water of Milli-Q purity was prepared with a Simplicity^® Water Purification System (Merck Millipore, Burlington, MA, USA).

Vacuette® 9 mL tubes without additives were obtained from Greiner Bio-One International GmbH (Kremsmünster, Kirchdorf an der Krems District, Austria). LC-MS grade methanol, acetonitrile (ACN) and formic acid (FA), HPLC grade absolute ethanol, chloroform and ammonia (32%), analytical grade ortho-boric acid, and sodium acetate trihydrate were purchased from VWR Chemicals (Radnor, PA, USA). 1,3-bis[tris(hydroxymethyl)methylamino]propane (bis-tris propane) (98+%) was purchased from Alfa Aesar (Haverhill, MA, USA). Alpha-1-acid glycoprotein from human plasma (≥99%), molecular biology grade K₂HPO₄, sodium dodecyl sulfate (SDS), ß-mercaptoethanol (ß-ME), and ethylenediaminetetraacetic acid (EDTA) were obtained from Sigma Aldrich (St. Louis, MO, USA). Sodium cyanoborohydride (95%) was purchased from Acros Organics (Geel, Belgium). Fractogel TMEA-650 (M) was obtained from Merck (Darmstadt, Germany). AA (≥99%) and molecular biology grade NaCl were obtained from Fisher Scientific (Hampton, NH, USA). Peptide:N-glycosidase F (PNGase F) was purchased from Roche Diagnostics (Mannheim, Germany). Sephadex G-25 Superfine gel was purchased from GE Healthcare (Chicago, IL, USA). Water of Milli-Q (MQ) purity prepared by Simplicity® Water Purification System (Merck Millipore, Burlington, MA, USA) was used.

Certified reference standard solutions of STX, dcGTX2+3, C1+2, C3+4, GTX1+4, GTX2+3, GTX5, GTX6, NEO and dcNEO were obtained from CIFGA laboratory S.A. (Lugo, Spain), while a certified reference standard solution of dcSTX (CRM-dSTX-b) was purchased to the National Research Council Canada (Halifax, Canada). The volume of each certified reference material (CRM) ampoule was quantitatively transferred and distributed by different glass recipients (vials), that were stored in frozen conditions (below—18 °C) until required. From each vial, different intermediate solutions were prepared using ultrapure water obtained using a Simplicity^® Water Purification System (Merck, Darmstadt, Germany, 18.2 MΩ·cm).
Pro-analysis (p.a.) reagents (NaOH, Na₂HPO₄.2H₂O) from Chem-Lab, H₅IO₆ (≥99.0%) from Sigma-Aldrich, and NH₄HCO₂ LC-MS grade from Carlo Erba were used to prepare the aqueous solutions, using ultrapure water. Glacial acetic acid (HPLC grade, ≥99.8%), from Carlo Erba, were used to stop oxidation reactions and to prepare diluted CH₃COOH solutions (1 M, 0.1 M, 0.1 mM). Acetonitrile (CH₃CN) HPLC grade (≥99.9%) from Honeywell was used as eluent. PVDF membrane filters (0.22 µm, 47 mm) from Teknokroma were used to filter the solvents, prior to HPLC analysis.