Determination of phenylalanine in blood by high-performance anion-exchange chromatography-pulsed amperometric detection to diagnose phenylketonuria

We have developed a high-performance anion-exchange chromatography with pulsed amperometric detection method for the detection of phenylalanine (Phe) and diagnosis of phenylketonuria (PKU). Sample pretreatment steps were simplified without derivatization. The analyte was separated within 5 min. The detection limit (S/N = 3) for Phe was 50 pg. Linear dynamic range was 1.23-14.43 mg/dL (r(2) = 0.9999) for a dried blood spot. The mean recoveries of Phe for intra- and inter-clay assays were found to be 96.87-104.16%. This method clearly differentiated PKU-positive groups from normal groups, and proved to be a practical procedure for rapid screening and follow-up monitoring of PKU. (C) 2009 Elsevier B.V. All rights reserved.