Iron chloride tetrahydrate

Iron (III) chloride hexahydrate (FeCl₃·6 H₂O); iron chloride tetrahydrate (FeCl₂·4 H₂O; ammonium persulfate (APS); N,N,N′-Trimethylethylenediamine 97% (TEMED); triethyl amine (TEA); acryloyl chloride; potassium carbonate (K₂CO₃); dibasic sodium phosphate (Na₂HPO4); and glycine (C₂H₅NO₂) were obtained from Sigma Aldrich (St. Louis, MO, USA). Ammonium hydroxide (NH₄OH) was purchased from EMD Chemicals (Gibbstown, NJ, USA). Poly(ethylene glycol) 400 dimethacrylate (PEG400DMA) was obtained from Polysciences INC. (Warrington, PA, USA). Curcumin was purchased from Chem-Impex International, Inc. (Bensenville, IL, USA), and quercetin was purchased from Cayman Chemicals (Ann Arbor, MI, USA). Citric acid monohydrate, sodium chloride (NaCl), calcium carbonate (CaCO₃), and sodium hydroxide (NaOH) were obtained from Fisher Scientific (Hannover Park, IL, USA). 3,3′,4,4′,5-Pentachlorobiphenyl (PCB-126) in Isooctane was purchased from Accustandard (New Haven, CT, USA). 5′-fluoro-3,3′,4,4′,5-pentachlorobiphenyl (F-PCB 126) was purchased from Resolution Systems Inc. (Holland, MI, USA). All solvents (Isooctane, ethanol HPLC grade, tetrahydrofuran (THF), dichloromethane (DCM), acetonitrile (ACN), and acetone) were obtained from Fisher Scientific (Hannover Park, IL, USA). All materials were used as received.

Iron(III) chloride solution 45%, iron chloride tetrahydrate ≥99%, iron(II) sulfate heptahydrate ≥99%, iron(III) nitrate nonahydrate >99.99%, sodium nitrate ≥99%, sodium hydroxide ≥98%, potassium hydroxide >85%, potassium nitrate >99%, nitric acid >65%, hydrochloric acid >37%, sulfuric acid 0.01 M, ammonium hydroxide solution 28%, poly (sodium acrylate) PAANa Mw of 2100 Da and triethylene glycol (TREG) 99% were bought from Sigma Aldrich (St. Louis, MO, USA) and used as received.

Graphite powder (particle size 20 μm), tetraethyl orthosilicate (TEOS), (3-aminopropyl) triethoxysilane (APTES), n-hydroxysuccinimide (NHS), 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC·HCl), and 1,8-dihydroxyanthraquinone (DHAQ) were purchased from Sigma-Aldrich, Ltd. Co. All other chemicals such as sodium nitrate (NaNO₃), potassium permanganate (KMnO₄), sulfuric acid (H₂SO₄), hydrochloric acid (HCl), hydrogen peroxide aqueous solution (H₂O₂), iron chloride hexahydrate (FeCl₃, 6H₂O), and iron chloride tetrahydrate (FeCl₂, 4H₂O) were of reagent grade and used without further purification.

Hydrochloric acid (HCl, 34%), and acetone (C₃H₆O, >99%), were bought from VWR Chemicals, UK. Anhydrous sodium hydroxide (NaOH, 98%), iron(iii) acetylacetonate (Fe(acac)₃, 99.9%), manganese(ii) acetylacetonate (Mn(acac)₂, 99.9%), manganese(iii) acetylacetonate (Mn(acac)₃, 99.9%), tetraethylene glycol (TEG, 99%), manganese(ii,iii) oxide (Mn₃O₄, 97%), manganese standard for inductively coupled plasma (ICP), TraceCERT®, 1000 mg L⁻¹ Mn in HNO₃, iron standard for ICP (TraceCERT®, 1000 mg L⁻¹ Fe in HNO₃), iron chloride tetrahydrate (FeCl₂·4H₂O ≥ 99%), nitric acid (HNO₃, 70%), potassium bromide (KBr, FTIR grade 99%), tri-sodium citrate dihydrate (Na₃C₆H₅O₇·2H₂O), hydroxylamine hydrochloride (ACS reagent, 98.0%), sodium acetate (Na-acetate, anhydrous, ReagentPlus®, ≥99.0%) and 1,10-phenanthroline monohydrate (titration ≥ 99.5%) were obtained from Sigma-Aldrich (UK). Absolute ethanol (C₂H₅ OH, 99.9%) was purchased from HaymanKimia, UK.