Kapton polyimide film

Kapton (polyimide) film (electrical grade polyimide film, 0.005″ thick) was obtained from McMaster-Carr (Elmhurst, IL, United States). Potassium ferrocyanide [K₄Fe(CN)₆] and potassium ferricyanide [K₃Fe(CN)₆] were obtained from Thermo Fisher Scientific (Waltham, MA, United States). Potassium chloride (KCl), chloroplatinic acid solution (H₂PtCl₆), and lead (II) acetate trihydrate [Pb(CH₃CO₂)₂·3H₂O] were purchased from Sigma Aldrich (St. Louis, MO, United States). Ag/AgCl (3 M KCl) reference electrode (Catalog number: MF-2056) and platinum auxiliary electrode (7.5 cm, Catalog number: MW-1032) were obtained from BASi® (West Lafayette, IN, United States).

Copper sulfate (CuSO₄), ethanol (C₂H₅OH), potassium ferrocyanide (K₄Fe(CN)₆), phosphate-buffered saline (PBS) solution, sodium sulfate (Na₂SO₄), magnesium chloride (MgCl₂), aluminum chloride (AlCl₃), mercury (II) nitrate hydrate (H₂HgN₂O₇), sodium hydroxide (NaOH), hydrochloric acid (HCl), ammonium nitrate (NH₄NO₃), humic acid salt, atrazine, glufosinate-ammonium, and chlorpyrifos were obtained from Fisher Scientific (Waltham, MA, USA). Potassium nitrate (KNO₃), potassium chloride (KCl), sodium bicarbonate (NaHCO₃), calcium chloride (CaCl₂), magnesium sulfate (MgSO₄), ammonium chloride (NH₄Cl) silver/silver chloride paste (Ag/Ag/Cl), glyphosate [N-(phosphonomethyl)glycine], (aminomethyl)phosphonic acid (AMPA), phosphoric acid (H₃PO₄), and a certified reference material 44,690-U for glyphosate (1000 μg⋅mL⁻¹ solution in distilled water) were purchased from Sigma Aldrich Inc. (St. Louis, MO, USA). Kapton™ (polyimide) film (electrical grade polyimide film, 0.0050″ thick) was obtained from McMaster-Carr (Elmhurst, IL, USA). Calcium sulfate was obtained from Watson (Caruthers, California, USA). Roundup® was bought from a local agricultural store (Bayer Inc., Whippany, NJ, USA).