Trisodium citrate dihydrate

Silver nitrate was purchased from Jingming Chemical, Taiwan. Sodium hydroxide, citric acid monohydrate, trisodium citrate dihydrate, and magnesium sulfate anhydrous were purchased from SHOWA, Japan. Sodium borohydride, copper (II) nitrite trihydrate, and sodium nitrite were purchased from ACROS, USA. Glycerol and iron (III) nitrate nonahydrate were purchased from Alfa Aesar, USA. Hg (II) nitrate hydrate and nickel (II) nitrate hexahydrate were purchased from VETEC, USA. Lead (II) nitrate was purchased from J.T. Baker, USA. Nitric acid and hydrochloric acid were purchased from AENCORE, Australia. The mercury standard solution (1000-μg/mL Mercury AA Standard Solution) was purchased from AccuStandard, New Haven, CT, USA.
Edible salts such as Unification of Life sun-dried sea salt (origin: Spain), Taiyen Biotech iodized high-quality salt (origin: Taiwan), and Marsel natural fine sea salt (origin: Belgium) were purchased from Carrefour, Taiwan. Taiyen Biotech healthy iodized sea salt (origin: Taiwan), Unification of Life sun-dried iodized sea salt (origin: Melbourne, Australia), and Natural Salt New Zealand sun-dried natural sea salt (origin: Marlborough, New Zealand) were purchased from PX mart, Taiwan. Kirkland Signature pure sea salt (origin: Australia) was purchased from Costco Wholesale Corporation, Taiwan.

All regents were analytical purity and used without further purification. Potassium hexacyanoferrate(III) (K₃[Fe(CN)₆], 99%) was bought from Riedel-de-Haën. Trisodium citrate dihydrate (C₆H₅Na₃O₇‧2H₂O, 99%) was obtained from SHOWA. Hydrochloric acid (HCl, 36%) was bought from BASF. Manganese(II) acetate (C₄H₆MnO₄, 98%), and tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) dichloride complex (Ru(ddp)₃Cl₂, C₇₂H₄₈C_l2N₆Ru) were obtained from Alfa Aesar. Ethanol (C₂H₅OH, 99.9%) was purchased from J. T. Baker. Aminophenyl fluorescein solution (APF, C₂₆H₁₇NO₅, 98%) was acquired from Life Technologies. Cobalt(II) acetate (C₄H₆CoO₄, 99%), Nickel(II) acetate tetrahydrate (C₄H₆NiO₄‧4H₂O, 98%), Polyvinylpyrrolidone (PVP, (C₆H₉NO)n, M.W. = 55,000), hydrogen peroxide solution (H₂O₂, 30%), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC, C₄₄H₈₄NO₈P, 99%), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE, C₄₁H₇₈NO₈P, 99%), potassium iodide (KI, 99.5%), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT, C₁₈H₁₆BrN₅S, 97.5%) were bought from Sigma-Aldrich. Water was obtained by using a Millipore direct-Q deionized water system throughout all studies.