Pentafluoropropionic anhydride pfpa

Unlabeled metformin (metformin-d₀), unlabeled creatinine (d₀-creatinine), trideutero-creatinine, i.e., [methylo-²H₃]creatinine (d₃-creatinine; declared isotopic purity of >99 atom% ²H), and [guanidino-²H₆]dimethylmetformin (declared isotopic purity of >99 atom% ²H) were purchased from Sigma-Aldrich (Steinheim, Germany). Pentafluoropropionic anhydride (PFPA) was from Thermo Scientific (Dreieich, Germany). Daily prepared solutions of PFPA in ethyl acetate (1:4, v/v) were used for the derivatization of metformin. Stock solutions were prepared in deionized water and stored in a refrigerator at 8 °C. Glassware for GC–MS (i.e., 1.5 mL autosampler glass vials and 0.2 mL microvials) and a fused-silica capillary column Optima 17 (15 m × 0.25 mm I.D., 0.25 µm film thickness) were purchased from Macherey-Nagel (Düren, Germany).

¹³C₄-spermidine (¹³C₄-SPD, 99% ¹³C) hydrochloride was obtained from Biomol (Hamburg, Germany) and was standardized as reported elsewhere [9 (link)]. It was tested as the internal standard for SPD, PUT, AGM, and HA. [α,α,β,β-²H₄] Histamine dihydrochloride (98% ²H, d₄-HA) and ethyl acetate were obtained from Merck (Darmstadt, Germany). Toluene and the hydrochloride salts of the unlabelled amines (chemical purity, 97%) were purchased from Sigma (Deisenhofen, Germany). Pentafluoropropionic anhydride (PFPA) was obtained from ThermoScientific (Dreieich, Germany) and used as the derivatization reagent for the amines. Glassware (1.8-mL autosampler vials and micro inserts) was purchased from Macherey-Nagel (Düren, Germany) and used in GC-MS analyses. Aqueous solutions of unlabelled and stable-isotope labelled amines were prepared in 10 mM HCl, diluted with distilled water as appropriate, and stored at −20 °C.
Safety Considerations. PFPA is corrosive and malodorous. Inhalation and contact with the skin and eyes should be avoided. All work should be and was performed in a well-ventilated fume hood.