The application of HPLC/ESI tandem mass spectrometry on urine‐soaked filter‐paper strips for the screening of disorders of purine and pyrimidine metabolism

Inherited disorders of purine and pyrimidine metabolism have a wide variety of clinical presentations that are often non-speciÐc, and severity of individual cases ranges from fatal to asymptomatic.Because of this broad clinical spectrum, a simple, rapid and speciÐc screening method is desired for the diagnosis of these disorders.Several high-performance liquid chromatography (HPLC) methods for screening for these disorders have been reported (Duran et al 1997 ;Sumi et al 1995), but so far these methods are time-consuming and non-speciÐc.Connection of HPLC with tandem mass spectrometry (MS/MS) has the advantage of rapidity and speciÐcity.We describe an analytical method for routinely screening disorders of purine and pyrimidine metabolism on urine-soaked Ðlter-paper strips using reversed-phase HPLC coupled with electrospray ionization (ESI) MS/MS.This method enables easy sample collection, even from the patientÏs home, mailing and storage (Blau et al 1998 ;McCann et al 1995).