Silver chloride agcl

Cytochrome c from equine heart (ref. C7752: MW~12.4 kDa, purity ≥ 95%), acetic acid (glacial), and Dulbecco’s Phosphate Buffered Saline (pH 7.4) were purchased from Sigma-Aldrich (Buchs, Switzerland). Sodium chloride and sodium acetate were obtained from Fisher Scientific (Loughborough, UK) and Fluka (Buchs, Switzerland), respectively.
Silver wire and silver chloride (AgCl) for the preparation of electrodes were obtained from Sigma Aldrich (Steinheim, Germany). PVC tubing (3 mm ID, 5 mm OD, and 1 mm wall) and agarose (used to prepare salt bridge assemblies) were obtained from VWR International AG (Dietikon, Switzerland) and Conda (Madrid, Spain), respectively.
The organic solvents, acetonitrile (ACN) and methanol (MeOH), were HPLC grade (Fischer Scientific, Loughborough, UK). Trifluoroacetic acid (TFA; 99% extra pure) was obtained from Acros organics (Geel, Belgium). Ultra-pure water (Millipore Milli-Q Gard 1 Purification pack resistivity > 18 MΩ.cm; Zug, Switzerland) was used to prepare all solutions. All other chemicals were at least of analytical grade.

Sodium chloride (NaCl) and sodium phosphate dibasic (Na₂HPO₄) were purchased from Fisher Scientific (Loughborough, UK); potassium phosphate monobasic (KH₂PO₄) was purchased from Sigma-Aldrich (Tokyo, Japan), HEPES (N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid) was obtained from Acros Organic (Geel, Belgium). Silver chloride (AgCl, metal basis > 99.99% purity) and silver (Ag) wire 1 mm Ø (>99.99% purity) were sourced from Sigma-Aldrich (Gillingham, UK). Amino acid l-tryptophan (Trp, ≥98% HPLC) was purchased from Sigma-Aldrich (Shanghai, China) and l-kynurenine (Kyn, metabolite of tryptophan, ≥98% HPLC) was from Sigma-Aldrich (Buchs, Switzerland). Glycerol monooleate (RYLO^TM MG 19 Pharma, Batch nr. 4010989490, monoglyceride content > 95% w/w, M_r = 356.6 g/mol) was kindly provided by Danisco Cultor (Brabrand, Denmark). PBS buffer (130.9 mM NaCl, 5.1 mM Na₂HPO₄ and 1.5 mM KH₂PO₄, pH of 7.4) and HEPES buffer (10 mM HEPES, 60 mM NaCl) were prepared in Milli-Q water (resistivity ≥ 18.2 MΩ·cm) and degassed by sonication for one hour prior to use. Methanol of HPLC grade was obtained from VWR international (Lutterworth, UK).