title: Extractions of pyrroloquinoline quinone from crude biological samples.
abstract: The best conditions for extractions of free pyrroloquinoline quinone (PQQ) from crude biological samples were investigated with various organic solvents and Sep-Pak C18 cartridges. PQQ was measured with use of its native fluorescence in aqueous solution. PQQ was well extracted into n-butanol under acid conditions, and addition of NaCl did not improve the solvent extraction. PQQ, which had been extracted into n-butanol, could be re-extracted into an aqueous phase by addition of either n-heptane or pyridine, or combination of them. PQQ, which had been adsorbed to Sep-Pak C18 cartridges, could be eluted with a mixture of pyridine and water with very excellent recovery. The recovery of 1 micrograms PQQ, which had been added to 1 g human liver, brain and 1 ml plasma and had undergone the n-butanol and the Sep-Pak extractions, was 50, 75 and 105%, respectively. From the blank fluorescence, endogenous levels of free PQQ in human liver, brain and plasma were found not greater than 0.41, 0.08 and 0.13 micrograms/g or ml, respectively, if present.
authors.affiliation: Department of Legal Medicine, Hamamatsu University School of Medicine, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Kumazawa
authors.forename: H
authors.initials: H
authors.lastname: Seno
authors.forename: T
authors.initials: T
authors.lastname: Urakami
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
mesh_terms: D001923:Brain Chemistry; D002851:Chromatography, High Pressure Liquid; D005453:Fluorescence; D006801:Humans; D008099:Liver / Q000737:chemistry; D045542:PQQ Cofactor; D015363:Quinolones / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification*; D012997:Solvents
chemical_list: D015363:Quinolones; D012997:Solvents; D045542:PQQ Cofactor