"Determination of plasma phenylalanine concentration by two dimensionalthin layer chromatography and high performance liquid chromatography in relation with diagnosis of phenylketonuria "

Abstract

Phenylketonuria (PKU) is a genetic disorder which can lead to serious long-term complications in children, including intellectual impairment. The cerebral damage can be largely eliminated if hyperphenilalaninemia (HPA) and PKU is detected by newborn screening and the dietary treatment (started no later than 10 days after birth), brings within 15 days the blood Phe level in the ranges 2 -6 mg/dL (or equivalently 120 -360 µmol/L). Consequently, the measurement of plasma Phe level in children with PKU is of utmost importance. We present here in detail two methods for determination of plasma Phe concentrations in children with HPA (detected by newborn screening) or suspected to have PKU based on clinical symptoms. The first method, involving two-dimensional thin-layer chromatography (2D -TLC) on micro scale chromatograms, allows the identification of patients with PKU. However, the quantitation of plasma Phe concentration by the 2D -TLC video-densitometric method is only semiquantitative, because is accompanied

Electrochemical Determination of Phenylalanine in Biological, Food and Pharmaceutical Samples using a MnO2/N‐doped Reduced Graphene Oxide Nanocomposite

“…Treatment in patients with phenylketonuria includes reducing the level of phenylalanyl below the allowable level (between 120–360 μmol L −1 ) by prescribing an appropriate diet, which should be started from the first weeks of life. Otherwise, it will cause mental retardation of the child and will cause irreparable damage to the patient and his family and community [6] . For these reasons, the determination of phenylalanine in body fluids and foods is very important and vital.…”

“…Otherwise, it will cause mental retardation of the child and will cause irreparable damage to the patient and his family and community. [6] For these reasons, the determination of phenylalanine in body fluids and foods is very important and vital. So far, many methods including chromatography, [7,8] UV-Vis spectroscopy, [9] and electrochemical voltammetry [10][11][12][13] have been reported for this purpose.…”

A Biochemical Method for Tyrosine Determination in Phenylketonuria Using a Colorimetric Enzymatic Approach

“…Since PAH assisted reaction is substrate dependent, its relevance should be considered in the events associated with high Phe blood levels [17]. Phenylalanine is competing with Tryptophan and Tyrosine for an amino acid transporter (blood-brain barrier).…”