Publications by authors named "Heleno Jose Bezerra Costa Netto"
Background: The present work describes an analytical method for urinary pterins by LC-MS/MS, with emphasis on the separation of 6- and 7-positional isomers of bio- and neopterins.
Results: Urine sample preparation consisted of oxidation by MnO(2), filtration and direct dilution in the mobile phase. The method was validated in urine spiked at five concentration levels with true triplicates of each level.