title: Retention of [(18)F]fluoride on reversed phase HPLC columns.
abstract: As [(18)F]fluoride is a starting reagent in the radiosynthesis of most fluorine-18 labeled positron emission tomography (PET) tracers, its chromatographic behavior on reversed phase (RP) HPLC columns is important for the purification performance and accuracy of RP HPLC quality control methods. We have investigated the chromatographic behavior and recovery of [(18)F]fluoride as a function of the type and brand of RP HPLC column, the pH and the composition of the mobile phase. Elution and elution profile of [(18)F]fluoride from six RP-HPLC columns (Waters XBridge C18 3 mm × 100 mm 3.5 μm; Grace Platinum EPS C18 4.6 mm × 100 mm, 3 μm; Waters XTerra C18 4.6 mm × 250 mm, 5 μm; Phenomenex C18 4.6 mm × 150 mm, 5 μm; Hamilton PRP-1 column 4.1 mm × 150 mm, 5 μm; Merck KGaA Chromolith Performance C18 3 mm × 100 mm) eluted with mobile phase composed of phosphate or acetate buffers (pH 2, 3, 4, 5, 7.3 and 9) and acetonitrile or ethanol as organic modifier were characterized. The elution profile was determined by on-line radioactivity measurement in the column eluate and recovery was calculated by comparison of radioactivity eluted with the HPLC column present or absent in the chromatographic flow path. Interestingly, [(18)F]fluoride recovery increased with increasing pH. At pH 3 all packed silica-based columns showed significant retention of fluorine-18, whereas almost no retention was observed on a polymeric PRP-1 column. However at pH 5, [(18)F]fluoride recovery was above 90% for each tested column. In addition, small differences were observed when changing the composition of the mobile phase. We therefore recommend to use a mobile phase with pH > 5 for silica based C18 columns for both quality control and semi-preparative HPLC of fluorine-18 labeled PET radiopharmaceuticals. If required a lower pH can be used in combination with a polymer based HPLC column.
authors.affiliation: Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences KU Leuven, Leuven, Belgium.
authors.forename: Dieter
authors.initials: D
authors.lastname: Ory
authors.affiliation: Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences KU Leuven, Leuven, Belgium.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Van den Brande
authors.affiliation: Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven and UZ Leuven, Leuven, Belgium.
authors.forename: Tjibbe
authors.initials: T
authors.lastname: de Groot
authors.affiliation: Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven and UZ Leuven, Leuven, Belgium.
authors.forename: Kim
authors.initials: K
authors.lastname: Serdons
authors.affiliation: Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven and UZ Leuven, Leuven, Belgium.
authors.forename: Marva
authors.initials: M
authors.lastname: Bex
authors.affiliation: Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences KU Leuven, Leuven, Belgium.
authors.forename: Lieven
authors.initials: L
authors.lastname: Declercq
authors.affiliation: Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences KU Leuven, Leuven, Belgium.
authors.forename: Frederik
authors.initials: F
authors.lastname: Cleeren
authors.affiliation: Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences KU Leuven, Leuven, Belgium.
authors.forename: Maarten
authors.initials: M
authors.lastname: Ooms
authors.affiliation: Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven and UZ Leuven, Leuven, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: Van Laere
authors.affiliation: Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences KU Leuven, Leuven, Belgium.
authors.forename: Alfons
authors.initials: A
authors.lastname: Verbruggen
authors.affiliation: Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences KU Leuven, Leuven, Belgium. Electronic address: guy.bormans@pharm.kuleuven.be.
authors.forename: Guy
authors.initials: G
authors.lastname: Bormans
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D056148:Chromatography, Reverse-Phase / Q000379:methods; D005459:Fluorides / Q000737:chemistry*; D005462:Fluorine Radioisotopes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D011108:Polymers / Q000737:chemistry; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D005462:Fluorine Radioisotopes; D011108:Polymers; D019275:Radiopharmaceuticals; D012822:Silicon Dioxide; D005459:Fluorides
keywords: HPLC; PET; Quality control; Radiopharmaceuticals; [(18)F]Fluoride recovery