2,3,4,5,6-Pentafluorobenzyl bromide (PFB-Br), sodium nitrite (purity 99.99+%), sodium [15N]nitrite and sodium [15N]nitrate (declared as 99 atom% at 15N each) were obtained from Sigma-Aldrich (Steinheim, Germany). Toluene was purchased from Baker (Deventer, The Netherlands). Sodium bicarbonate and carbonate, acetone and glacial acetic acid were from Merck (Darmstadt, Germany). 2H-Labelled creatinine ([methylo-2H3]creatinine, >99 atom% 2H) was obtained from Aldrich. PFB-Br is corrosive and an eye irritant. Inhalation and contact with skin and eyes should be avoided. All work should be and was performed in a well-ventilated fume hood. Separate stock solutions of salts were prepared by dissolving accurately weighed amounts of commercially available unlabeled and stable-isotope-labeled salts in deionized water. Stock solutions were diluted with deionized water as appropriate.
Glassware for GC-MS (1.5-mL autosampler vials and 0.2-mL microvials) including the fused-silica capillary column Optima 17 (15 m × 0.25 mm I.D., 0.25-micrometer film thickness) were purchased from Macherey-Nagel (Düren, Germany).
Glassware for GC-MS (1.5-mL autosampler vials and 0.2-mL microvials) including the fused-silica capillary column Optima 17 (15 m × 0.25 mm I.D., 0.25-micrometer film thickness) were purchased from Macherey-Nagel (Düren, Germany).