Failure to verify high levels of pyrroloquinoline quinone in eggs and skim milk.
The levels of pyrroloquinoline quinone (PQQ) in eggs, skim milk and milk was re-examined by the use of gas chromatography/mass spectrometry. PQQ was extracted from the samples, after addition of [U-13C]PQQ as internal standard, with n-butanol and Sep-Pak C18 cartridges. After derivatization of PQQ with phenyltrimethylammonium hydroxide, molecular peaks at m/z 448 and 462 were used for detection of PQQ and [U-13C]PQQ, respectively, by selected ion monitoring. PQQ could be detected in eggs, skim milk and milk, but their levels were very low (e.g., egg yolk: 7.0 ng/ml; skim milk: 2.5 ng/g dry weight). Our data for eggs and skim milk are far below those measured by the redox cycling method of Gallop's group.
Department of Legal Medicine, Hamamatsu University School of Medicine, Japan.
T
T
Kumazawa
H
H
Seno
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O
Suzuki
D000818:Animals; D003067:Coenzymes / Q000032:analysis*; D004531:Eggs / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D008892:Milk / Q000737:chemistry*; D045542:PQQ Cofactor; D011200:Poultry; D015363:Quinolones / Q000032:analysis*
D003067:Coenzymes; D015363:Quinolones; D045542:PQQ Cofactor